Cryoablation vs Thoracoscopic Resection in the Local Management of Pulmonary Metastases Including Primary Lung Cancer with Intrapulmonary Spread

Cryoablation vs Thoracoscopic Resection in the Local Management of Pulmonary Metastases Including Primary Lung Cancer with Intrapulmonary Spread | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Cryoablation vs Thoracoscopic Resection in the Local Management of Pulmonary Metastases Including Primary Lung Cancer with Intrapulmonary Spread Hsing-Hua Lai, Chien-Ming Lo, Yu Chen, Hung-I Lu, Kai-Hao Chuang, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9395764/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Background Surgical resection remains a commonly used local treatment option for selected patients with pulmonary metastases. However, a subset of patients, particularly those with limited pulmonary reserve or prior ipsilateral thoracic surgery, may not tolerate the procedure well. Percutaneous cryoablation is a less invasive option; however, comparisons of perioperative outcomes with those of surgery are limited. We aimed to compare the perioperative outcomes between these two modalities. Methods We retrospectively analyzed 85 patients with metastatic pulmonary tumors treated at a single tertiary center between June 2022 and September 2024. The patients underwent thoracoscopic pulmonary metastasectomy (n = 70) or percutaneous cryoablation (n = 15). Clinical parameters, including operative time, chest drainage, and length of hospital stay, were compared between the groups. Results Patients selected for cryoablation had a higher incidence of ipsilateral thoracic surgery (66.7% vs . 18.6%; P < 0.001) than those selected for thoracic surgery. Although the average procedure time was longer (4.26 vs . 2.22 h, P = 0.123), the need for chest tube placement (46.0% vs . 2.8%, P = 0.000) and the number and size of drains were significantly lower (P < 0.01) in the cryoablation group versus the thoracic surgery group. The length of hospital stay was similar in both groups. Conclusions In selected patients, particularly those with previous thoracic interventions or impaired pulmonary function, percutaneous cryoablation may be a less invasive and tubeless alternative to surgery. These findings support its role as a practical local treatment option when surgery is contraindicated or carries increased risk. Cryoablation Minimally invasive treatment Perioperative outcomes Pulmonary metastasis Thoracoscopic resection Background The lungs are a common site of metastasis from various malignancies, particularly those originating from the breast, lung, head and neck, colon, rectum, and liver.[ 1 ] Although surgical resection remains the standard of care for these patients when feasible,[ 2 ] many patients are not considered suitable surgical candidates owing to limited pulmonary function, multiple prior thoracic surgeries, comorbidities, advanced age, or personal refusal of surgery.[ 1 ] In addition to surgery, several local treatment modalities have recently become available for patients with small non-small-cell lung cancer and oligometastatic diseases. These include stereotactic ablative radiotherapy and percutaneous thermal ablative therapies, such as radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation (CA), and irreversible electroporation,[ 3 ] which have been compared in previous studies.[ 4 ] The optimal treatment strategy should be developed based on tumor location and individual clinical condition.[ 1 ] Image-guided percutaneous CA offers the distinct advantage of real-time visualization of the ablation zone using computed tomography (CT), characterized by interstitial or consolidative changes or the formation of visible ice. This facilitates effective tumor destruction while minimizing injury to the surrounding normal lung parenchyma.[ 5 – 7 ] CA may be more effective than RFA or MWA in certain settings.[ 8 ] A major advantage of CA over surgical resection is its ability to preserve lung parenchyma and maintain pulmonary function.[ 9 ] However, few studies have directly compared the perioperative outcomes between surgical resection and percutaneous CA. Therefore, the present study aimed to compare the perioperative outcomes between these two modalities. Methods Ethical Statement The experimental protocol was established in accordance with the ethical guidelines of the Declaration of Helsinki and was approved by the Institutional Review Board of XXXX Hospital (approval number: 202500763B0, 2025/5/23). Given its retrospective design, the requirement for informed consent was waived. This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Patient selection We retrospectively reviewed the electronic medical records of patients with pulmonary metastatic tumors who underwent either surgical resection or percutaneous CA between June 2022 and September 2024 at XXXX Hospital. All patients were evaluated by a multidisciplinary team comprising surgeons, thoracic surgeons, oncologists, and radiologists. The inclusion criteria were age ≥18 years, confirmed pulmonary metastatic disease, and a history of either lung surgery or percutaneous CA as local treatment. Patients who underwent combined surgeries involving other metastatic sites were excluded owing to the potential for prolonged operative time. A total of 88 patients met the inclusion criteria. Overall, 3 patients were excluded because they underwent combined surgeries, resulting in a final cohort of 85 patients. Treatment Plan After confirming that the primary malignancy was under control or that the patient had oligometastatic disease, a multidisciplinary team comprising thoracic surgeons, general surgeons, oncologists, and radiologists conducted a comprehensive evaluation. This included assessments of pulmonary and cardiac function, Eastern Cooperative Oncology Group performance status, and the patient’s financial condition. The risks and benefits of both treatment options were thoroughly discussed with patients and their families. The feasibility of wedge resection was carefully evaluated, particularly for large or centrally located tumors, where achieving an adequate surgical margin could be technically challenging or oncologically insufficient. Anatomical resection, including segmentectomy or lobectomy, was required when wedge resection could not ensure safe surgical margins. The treatment plan was finalized when a consensus was reached between the patient and the multidisciplinary team. Chest CT was performed within 4 weeks before treatment to confirm the status of the metastatic lesions. Bilateral pulmonary metastases were treated simultaneously in a single session whenever clinically feasible. For patients with multiple pulmonary metastases, the treatment goal was to achieve complete resection or ablation of all visible lesions in a single session whenever technically feasible. Staged procedures were considered only when simultaneous treatment of all lesions was not technically possible or carried excessive risk. Thoracic surgery Thoracoscopic wedge resection was initially considered for all patients undergoing thoracic surgery. In cases where a safe surgical margin could not be achieved, particularly for large or centrally located tumors, anatomical resection, including thoracoscopic segmentectomy or lobectomy, was performed. Each surgery was performed by one of the five thoracic surgeons. Consistency was maintained across cases in terms of operating room setup, surgical team composition, and instrumentation. For patients with bilateral pulmonary metastases, resections were performed in a single-stage operation via sequential thoracoscopic approaches rather than staged procedures. CA procedure Percutaneous CA was performed in a hybrid operating room under general anesthesia with single-lumen endotracheal intubation. CA needles (17-gauge; Galil Medical, Inc., Boston Scientific Corporation, Marlborough, MA, USA) were placed under the guidance of a Siemens Artis Zeego cone-beam CT system to ensure that the ice ball fully encompassed the index tumor(s) with an adequate ablative margin. The number and configuration of the needles were determined based on the distance between the tumor margins and needle placement to achieve optimal coverage. CA typically followed a three-cycle freeze–thaw protocol, and the procedure was monitored using the Zeego system with cone-beam CT performed at 3- to 5-min intervals to assess the ablation zone. The goal was to ensure that the ice ball completely encompassed the tumor with an adequate margin to achieve effective ablation.[1] For patients with multiple tumors, intraoperative repositioning, repeated puncture, and resterilization were often required to facilitate accurate needle placement, ensure complete ablation of all target lesions, and minimize the risk of injury to adjacent critical structures. Upon completion of the ablation protocol, a follow-up cone-beam CT scan was performed approximately 10 min later to confirm successful ice ball formation and assess for procedure-related complications such as pneumothorax. If pneumothorax was detected during or after the procedure, thoracostomy was performed. The chest tube size was selected based on the extent of the pneumothorax. All cryoablation procedures were performed under general anesthesia with single-lumen endotracheal intubation. This approach was chosen because cryoablation sessions are typically prolonged and often require multiple breath-holding cycles. Controlled ventilation allowed for consistent lung expansion during CT scanning and needle placement, ensuring accurate alignment of the puncture trajectory with imaging. In addition, patient repositioning was frequently required to access multiple lesions or avoid critical structures, and maintaining these positions was more feasible under general anesthesia. Finally, in the event of acute complications such as hemothorax, general anesthesia enabled immediate surgical intervention if necessary. Similarly, in the cryoablation group, patients with bilateral pulmonary metastases underwent single-session procedures, with both lungs treated during the same intervention under CT guidance. Data collection Data collected included patient age, sex, primary tumor origin, tumor histology, type of surgery performed (wedge resection, segmentectomy, or lobectomy), history of prior ipsilateral pulmonary surgery, treated side, number of treated tumors, maximum tumor size, presence of postoperative drainage, number of drainage tubes, and maximum drainage tube size (in French units, Fr). The operative time (in h) was defined as the interval from skin incision (for surgical cases) or initiation of the Zeego system (for CA cases) to patient extubation. The length of hospital stay was defined as the number of days from the procedure (either surgery or CA) to hospital discharge. Statistical analysis Continuous variables were expressed as mean ± standard deviation, and categorical variables were presented as frequencies and percentages. Group comparisons of continuous variables (e.g., operation time, length of hospital stay, drainage number, and maximum drainage size) between the CA and thoracic surgery groups were performed using independent sample t-tests. Categorical variables were compared using the chi-squared test or Fisher's exact test, as appropriate. Statistical significance was set at P < 0.05. All statistical analyses were performed using the SPSS software (version 23.0; IBM Corp., Armonk, NY, USA). Results Patient characteristics A total of 85 patients with pulmonary metastatic tumors were enrolled. The basic clinical parameters of the patients are summarized in Table 1. The mean age was 61.8 and 65.5, with a nearly equal sex distribution (44 men and 41 women). Among the 85 patients, 70 (82.4%) underwent thoracoscopic pulmonary metastasectomy (thoracic surgery), and 15 (17.6%) underwent percutaneous CA. There were no significant differences in age (P = 0.33) and sex (P = 0.561) between the two groups. Compared with patients who underwent thoracic surgery, those who underwent CA were significantly more likely to have undergone prior ipsilateral lung surgery (66.7% vs . 18.6%, P = 0.000), suggesting that this group had more complex surgical histories. Other factors, including tumor number (≤3 vs . >3, P = 0.144) and disease laterality (unilateral vs. bilateral, P = 0.088), did not significantly differ between the two groups. However, a higher proportion of patients in the CA group had tumors > 1 cm (80.0% vs . 42.9%, P = 0.009) than in the thoracic surgery group. Primary tumor origin Primary tumor origins are summarized in Table 1. The most common source was colorectal cancer, representing 21.4% of the thoracoscopic resection cohort and 46.6% of the cryoablation cohort. Lung cancer with intrapulmonary metastases was also frequent (21.4% and 13.3%, respectively), along with head and neck cancers. Less common categories included genitourinary, hepatobiliary, gynecologic, and breast malignancies. Rare entities such as thymoma and mesothelioma with intrapulmonary spread were grouped as “other/rare.” This classification underscores the wide oncologic spectrum of patients considered for local pulmonary treatments. Tumor histology Tumor histologies are summarized in Table 1. Adenocarcinoma was the predominant subtype, comprising nearly half of thoracoscopic resections (47.1%) and the majority of cryoablation cases (60%). Squamous cell carcinoma was the next most common, whereas sarcomas—including osteosarcoma and liposarcoma—were less frequent. Other histologies included urothelial carcinoma, melanoma, hepatocellular carcinoma, and adenoid cystic carcinoma, as well as a small number of rare variants. These findings reflect the heterogeneity of pulmonary metastases, which are addressed through surgical and ablative approaches. Surgical procedures Surgical procedures are summarized in Table 2. Non-anatomical wedge resections accounted for the majority of cases, with single or multiple wedge resections performed in 90% of thoracoscopic resections. A smaller number involved combined resections, such as wedge resection with chest wall or diaphragm resection. Anatomical resections were less frequent, including segmentectomy and lobectomy, which were performed selectively when adequate margins were required. This distribution highlights wedge resection as the dominant strategy in pulmonary metastasectomy, consistent with its balance of oncologic adequacy and parenchymal preservation. Perioperative outcomes All perioperative outcomes, including operative time, hospital stay, drainage-related parameters, and procedure-related costs, are summarized in Table 3. Although the mean operation time was longer in the CA group (4.26 ± 1.90 h) than in the thoracic surgery group (2.22 ± 1.28 h), the difference did not reach statistical significance (P = 0.123). The length of hospital stay was also similar between groups (CA: 4.00 ± 1.85 d vs . thoracic surgery: 4.73 ± 2.65 d, P = 0.307). In contrast, drainage-related outcomes significantly favored CA. Approximately half of the patients in the CA group (46.0%) were managed without thoracic drainage, compared with only 2.8% in the thoracic surgery group (P = 0.000). Additionally, compared with the thoracic surgery group, both the average number of drains (0.6 ± 0.63 vs . 1.11 ± 0.41, P = 0.001) and maximum drain size (7.07 ± 7.00 Fr vs . 20.92 ± 2.37 Fr, P = 0.000) were significantly lower in the CA group, indicating a less invasive profile and potentially improved perioperative comfort. The mean procedure-related cost was significantly higher in the cryoablation group compared with thoracoscopic resection (201,933 NTD vs. 53,107 NTD, P < 0.001) To further account for potential confounding factors, multivariable regression analyses were performed. Logistic regression for drainless management demonstrated that cryoablation remained independently associated with a higher likelihood of avoiding chest drainage (adjusted OR 0.044, 95% CI 0.005–0.429, P = 0.007). Linear regression models for drainage number and maximum drainage size similarly confirmed that the surgical method was the only significant predictor, whereas age, sex, prior ipsilateral thoracic surgery, and tumor size were not significant contributors. These adjusted results are presented in Supplementary Table 1. Discussion Minimally invasive local treatments, such as RFA, MWA, and CA, are increasingly used to manage pulmonary metastases. CA, in particular, has gained attention for its ability to preserve surrounding tissue, improve visualization, and reduce procedural pain.[3, 4, 9] These features may make it a viable option for lesions close to critical structures.[4, 9] Although some studies have shown that ablation therapies are comparable to surgery in certain settings,[10] direct comparisons between CA and surgical resection are limited. Our study aimed to provide insights into this comparison. In our cohort, CA procedures tended to take longer than thoracoscopic resection. This may reflect the need for multiple patient repositionings and repeated sterilization steps for accessing lesions in different lung segments. These logistical factors have also been noted in other studies, in which CA times widely varied depending on tumor location and number.[6, 11] Despite the longer procedure time, CA was associated with less frequent use of chest drainage tubes. This is consistent with previous reports suggesting that CA preserves lung parenchyma and reduces the risk of pneumothorax.[9] In our analysis, chest tube insertion could be avoided in approximately half of the CA group, thereby improving postoperative comfort. These findings remained consistent after adjustment for age, sex, prior ipsilateral thoracic surgery, and tumor size, with the surgical method being the only independent predictor of drainage outcomes (Supplementary Table 1). Importantly, no instances of pleural seeding or major complications requiring surgical management (e.g., refractory pneumothorax or empyema) were observed in our cohort. However, previous reports have documented cases of pleural seeding following cryoablation complicated by pneumothorax[12, 13], as well as severe complications necessitating surgical intervention[14]. This suggests that although our results are reassuring, long-term follow-up is necessary to fully evaluate these risks. When considering complete clearance of multiple pulmonary metastases in a single session, one limitation of thoracoscopic resection is that very small or deeply seated nodules may be difficult to localize or palpate intraoperatively, potentially preventing complete resection. By contrast, cryoablation under CT guidance can effectively target radiologically visible lesions, even when they are non-palpable. This capability may enhance the likelihood of achieving complete tumor clearance in a single procedure, particularly in patients with sub-centimeter or deep parenchymal nodules. A notable proportion of patients who underwent CA had a history of ipsilateral thoracic surgery. Reoperation in such cases is often technically challenging because of the pleural adhesions. For these patients, CA may offer a less invasive approach that avoids surgical reentry. In addition, CA is typically performed under moderate sedation or general anesthesia, without single-lung ventilation. This may help reduce the risk of ventilator-induced lung injury, particularly in patients with a limited pulmonary reserve. In contrast, thoracoscopic metastasectomy often necessitates the deflation of the operated lung, which can impose physiological stress and increase postoperative pulmonary risk. CA could be a reasonable alternative in patients with reduced cardiopulmonary function or surgical intolerance.[3, 4, 9] Although this study focused on the perioperative outcomes, long-term disease control remains a key consideration. Prospective trials have reported encouraging local control rates at 2–5 years with CA.[1, 6] Therefore, CA is a potential local therapy, particularly in well-selected oligometastasis cases. Future studies should compare long-term outcomes between pulmonary metastasectomy and percutaneous ablation, incorporate patient-reported quality-of-life measures, and further address rare but clinically relevant complications, including pleural dissemination and persistent pleural space problems, to establish optimal patient selection and follow-up protocols. Another important consideration is cost. Although cryoablation demonstrated favorable perioperative outcomes, its substantially higher procedure-related cost compared with thoracoscopic resection may limit broader adoption. The higher procedure-related cost of cryoablation in our series was largely attributable to device- and equipment-related expenses, as operative time was comparable between the two groups. In Taiwan’s healthcare system, thoracoscopic resection is largely reimbursed by the National Health Insurance (NHI), whereas cryoablation consumables are entirely self-funded. Thus, the actual out-of-pocket cost for surgery may be as low as one-tenth of the calculated procedure-related expense, whereas patients undergoing cryoablation bear the full cost. This reimbursement discrepancy limits the generalizability of our cost comparison and underscores the need to interpret financial outcomes within the context of local healthcare systems. This study has some limitations. This was a retrospective study, and patient selection may have influenced the observed outcomes. The heterogeneity of tumor histology and primary sites limits generalizability. Perioperative complications that may affect recovery and treatment decisions were excluded from the analysis. Long-term outcomes such as progression-free and overall survival were not assessed. Therefore, these aspects should be considered in future studies. Another limitation is the imbalance between the two treatment groups (thoracoscopic resection, n = 70; cryoablation, n = 15), reflecting real-world practice and the limited adoption of cryoablation at our center. Moreover, treatment allocation was non-randomized and influenced by clinical judgment and patient preference, which introduces potential selection bias. Although multivariable adjustment was performed, residual confounding cannot be excluded, and the results should therefore be interpreted with caution. Conclusion CA is a less invasive and tubeless alternative to thoracoscopic pulmonary metastasectomy, particularly in patients with a history of thoracic surgery or limited pulmonary reserve. Although the procedure time may be longer, the reduced need for chest tubes and avoidance of single-lung ventilation support the use of CA in selected cases. Declarations Ethical approval and consent to participate The experimental protocol was established in accordance with the ethical guidelines of the Declaration of Helsinki and was approved by the Institutional Review Board of XXXX Hospital (approval number: 202500763B0, 2025/5/23). Given its retrospective design, the requirement for informed consent was waived. Consent for publication Availability of data and materials All data generated or analyzed during this study are included in this published article. Competing Interests None Funding This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Authors’ contributions Acknowledgements We would like to thank Editage for providing language editing assistance. Declaration of generative AI and AI-assisted technologies in the writing process During the preparation of this work, the author(s) used ChatGPT to assist with refining the abstract, conclusion, and discussion; generating the graphical abstract and central picture legend; drafting the central message, ultramini abstract, and perspective statement; and formatting the case report form. The tool was also used to clarify journal-specific formatting requirements and to ensure language consistency throughout the manuscript. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the publication's content. References de Baère T, et al. The ECLIPSE Study: Efficacy of cryoablation on metastatic lung tumors with a 5-year follow-up. J Thorac Oncol. 2021;16:1840–9. de Baère T, et al. Evaluating cryoablation of metastatic lung tumors in patients–safety and efficacy: The ECLIPSE Trial–Interim analysis at 1 Year. J Thorac Oncol. 2015;10:1468–74. de Baère T, et al. Lung ablation: Best practice/results/response assessment/role alongside other ablative therapies. Clin Radiol. 2017;72:657–64. Prud'homme C, et al. Image-guided lung metastasis ablation: a literature review. Int J Hyperth. 2019;36:37–45. Ahmed A, Littrup P. Percutaneous cryotherapy of the thorax: safety considerations for complex cases. AJR Am J Roentgenol. 2006;186:1703–6. Callstrom MR, et al. Multicenter study of metastatic lung tumors targeted by interventional cryoablation evaluation (SOLSTICE). J Thorac Oncol. 2020;15:1200–9. Wang H, et al. Thoracic masses treated with percutaneous cryotherapy: initial experience with more than 200 procedures. Radiology. 2005;235(1):289–98. Zhang KQ, Zhang JR, Wei HM. Therapeutic effects of cryoablation, radiofrequency ablation, and microwave coagulation against VX2 liver cancer: a comparative study in rabbits. Nan Fang Yi Ke Da Xue Xue Bao. 2007;27:1431–4. Velez A, DeMaio A, Sterman D. Cryoablation and immunity in non-small cell lung cancer: a new era of cryo-immunotherapy. Front Immunol. 2023;14:1203539. Ohmoto K, et al. Comparison of therapeutic effects between radiofrequency ablation and percutaneous microwave coagulation therapy for small hepatocellular carcinomas. J Gastroenterol Hepatol. 2009;24:223–7. McDevitt JL, et al. Percutaneous cryoablation for the treatment of primary and metastatic lung tumors: Identification of risk factors for recurrence and major complications. J Vasc Interv Radiol. 2016;27:1371–9. Yamauchi Y, et al. Needle-tract seeding after percutaneous cryoablation for lung metastasis of colorectal cancer. Ann Thorac Surg. 2011;92:e69–71. Conners D, Rilling W. Pleural tumor seeding following percutaneous cryoablation of hepatocellular carcinoma. Semin Intervent Radiol. 2011;28:258–60. Vyas V, Paul M. A case of catastrophic complications following cryoablation of lung cancer. Chest. 2020;158:A1626. de Baère T, et al. The ECLIPSE Study: Efficacy of Cryoablation on Metastatic Lung Tumors With a 5-Year Follow-Up. J Thorac Oncol. 2021;16(11):1840–9. de Baere T, et al. Evaluating Cryoablation of Metastatic Lung Tumors in Patients–Safety and Efficacy: The ECLIPSE Trial–Interim Analysis at 1 Year. J Thorac Oncol. 2015;10(10):1468–74. de Baere T, et al. Lung ablation: Best practice/results/response assessment/role alongside other ablative therapies. Clin Radiol. 2017;72(8):657–64. Prud'homme C, et al. Image-guided lung metastasis ablation: a literature review. Int J Hyperth. 2019;36(2):37–45. Ahmed A, Littrup P. Percutaneous cryotherapy of the thorax: safety considerations for complex cases. AJR Am J Roentgenol. 2006;186(6):1703–6. Callstrom MR, et al. Multicenter Study of Metastatic Lung Tumors Targeted by Interventional Cryoablation Evaluation (SOLSTICE). J Thorac Oncol. 2020;15(7):1200–9. Wang H, et al. Thoracic masses treated with percutaneous cryotherapy: initial experience with more than 200 procedures. Radiology. 2005;235(1):289–98. Zhang KQ, Zhang JR, Wei HM. Therapeutic effects of cryoablation, radiofrequency ablation, and microwave coagulation against VX2 liver cancer: a comparative study in rabbits]. Nan Fang Yi Ke Da Xue Xue Bao. 2007;27(9):1431–4. Velez A, DeMaio A, Sterman D. Cryoablation and immunity in non-small cell lung cancer: a new era of cryo-immunotherapy. Front Immunol. 2023;14:1203539. Ohmoto K, et al. Comparison of therapeutic effects between radiofrequency ablation and percutaneous microwave coagulation therapy for small hepatocellular carcinomas. J Gastroenterol Hepatol. 2009;24(2):223–7. McDevitt JL, et al. Percutaneous Cryoablation for the Treatment of Primary and Metastatic Lung Tumors: Identification of Risk Factors for Recurrence and Major Complications. J Vasc Interv Radiol. 2016;27(9):1371–9. Yamauchi Y, et al. Needle-tract seeding after percutaneous cryoablation for lung metastasis of colorectal cancer. Ann Thorac Surg. 2011;92(4):e69–71. Conners D, Rilling W. Pleural tumor seeding following percutaneous cryoablation of hepatocellular carcinoma. Semin Intervent Radiol. 2011;28(2):258–60. Vyas V, Paul M. A CASE OF CATASTROPHIC COMPLICATIONS FOLLOWING CRYOABLATION OF LUNG CANCER. Chest. 2020;158(4):A1626. Tables Table 1 Patient characteristics Demographic Thoracoscopic Resection (n = 70) Cryoablation (n = 15) P-Value Mean age 61.8 65.5 0.33 Gender (Male/Female) 36/34 (1.05) 8/7 (1.14) 0.561 Primary tumor origin Colorectal (colon, rectum, cecum, ileum) 15 (21.4%) 7 (46.6%) 0.431 Lung (primary lung cancer with intrapulmonary spread) 15 (21.4%) 2 (13.3%) Hepatobiliary/pancreas (liver, bile duct, pancreas) 5 (7.1%) 0 Head & neck (oral cavity, pharynx, larynx, salivary gland) 12 (17.1) 2 (13.3%) Breast 3 (4.2%) 1 (6.6%) Gynecologic (endometrium, cervix, ovary, vagina) 4 (5.7%) 0 Genitourinary (kidney, bladder, prostate, testis, etc.) 6 (8.5%) 0 Sarcoma (osteosarcoma, liposarcoma, myxofibrosarcoma, etc.) 2 (2.8%) 0 Others/rare (thymoma, mesothelioma with intrapulmonary metastasis, thyroid medullary carcinoma, melanoma, etc.) 3 (4.2%) 2 (13.3%) Tumor histology (N/percentage) Adenocarcinoma 33 (47.1%) 9 (60%) 0.517 Squamous cell carcinoma 12 (17.1%) 1 (6.6%) Others 25 (35.7%) 5 (33.3%) Disease characteristics Number of tumors 3 Largest tumor > 1 cm 5 (7.1%) 65 (92.8%) 30 (42.8%) 3 (20%) 12 (80%) 12 (80%) 0.144 0.009 Unilateral disease 60 (85.7%) 10 (66.6%) 0.088 Bilateral disease 10 (14.2%) 5 (33.3%) Prior ipsilateral thoracic surgery 13 (18.6%) 10 (66.7%) < 0.001 VATS, video-assisted thoracoscopic surgery Table 2 Surgical procedure classification Total 70 Non-anatomical resection (wedge resection) Single wedge resection 26 (37.1%) Multiple wedge resection 37 (52.8%) Combined procedures (e.g., wedge with chest wall or diaphragm resection) 2 (2.85%) Anatomical resection Single segmentectomy 1 (1.4%) Single lobectomy 1 (1.4%) Combined procedure (segmentectomy or lobectomy with wedge resection) 3 (4.2%) Table 3 Comparison of perioperative outcomes between cryoablation and lung resection Parameter Thoracic surgery (N = 70) Cryoablation (N = 15) P-value Operation time (h) 2.22 ± 1.28 4.26 ± 1.90 0.123 Length of stay (d) 4.73 ± 2.65 4 ± 1.85 0.307 Drainless 2 (2.8%) 7 (46%) 0.000 Drainage number 1.114 ± 0.408 0.6 ± 0.632 0.001 Max drainage size (Fr) 20.92 ± 2.37 7.07 ± 7.00 0.000 Mean procedure-related cost (NTD) 53106.771 201933.333 0.000 Supplementary Table Supplementary Table 1. Multivariable regression analyses for drainage outcomes Outcome Significant Factor(s) Effect (B / OR) P-value Other Covariates Drainless (binary, logistic regression) Operation method (CA vs. VATS) OR = 0.044 (95% CI: 0.005–0.429) 0.007 Age, sex, prior ipsilateral surgery, tumor size → NS Drain number (linear regression) Operation method (CA vs. VATS) B = –0.43 0.005 Age, prior ipsilateral surgery, tumor size → NS; sex showed borderline trend (p = 0.056) Max drainage size (linear regression) Operation method (CA vs. VATS) B = –14.03 <0.001 Age, sex, prior ipsilateral surgery, tumor size → NS Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 12 May, 2026 Reviewers agreed at journal 29 Apr, 2026 Reviewers invited by journal 29 Apr, 2026 Editor assigned by journal 21 Apr, 2026 Submission checks completed at journal 21 Apr, 2026 First submitted to journal 12 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9395764","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":635398040,"identity":"4dcab41e-f31a-4890-a6cd-07505a4c2261","order_by":0,"name":"Hsing-Hua Lai","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2ElEQVRIiWNgGAWjYBACAzDJVsPDxt4DZvPwEanlmBw/zxkDhgNALWxEamE2lpyRA9bCQFCLOXuP4eeKMrbEDTffGD7+mGMnw8bA/PDRDTxaLHvOGEueOSeTuOF2/meDg9uSgQ5jMzbOweewG7kbJBvbgLbczjGTOLiNGaiFh02agJbNPxvbmIEOOwPSUk+Ulm1AW0De5wFpOUyEljPnv1k2nAMFco6xwdltx3nYmAn55Xhb8s2GMlBUnjF8ULmt2p6fvfnhY3xasABm0pSPglEwCkbBKMACAKRzSZpYWG9HAAAAAElFTkSuQmCC","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":true,"prefix":"","firstName":"Hsing-Hua","middleName":"","lastName":"Lai","suffix":""},{"id":635398045,"identity":"730db5ae-adf2-4791-a3d4-2d1c28f91d56","order_by":1,"name":"Chien-Ming Lo","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chien-Ming","middleName":"","lastName":"Lo","suffix":""},{"id":635398046,"identity":"65684066-a5f7-4c9b-a8fa-ac888dc9dae5","order_by":2,"name":"Yu Chen","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yu","middleName":"","lastName":"Chen","suffix":""},{"id":635398047,"identity":"0d8653cf-6c9f-49cd-9816-ec368260b97d","order_by":3,"name":"Hung-I Lu","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hung-I","middleName":"","lastName":"Lu","suffix":""},{"id":635398048,"identity":"fc99cbd7-1e8c-4241-a9f7-65bda9ef6550","order_by":4,"name":"Kai-Hao Chuang","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Kai-Hao","middleName":"","lastName":"Chuang","suffix":""},{"id":635398049,"identity":"e0e74203-4de0-4788-b67a-f6e3e93608a6","order_by":5,"name":"Li-Chun Chen","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Li-Chun","middleName":"","lastName":"Chen","suffix":""},{"id":635398050,"identity":"128daa4a-1da4-49b3-b109-6fcaf3391813","order_by":6,"name":"Yu-Hsin Hsiao","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yu-Hsin","middleName":"","lastName":"Hsiao","suffix":""},{"id":635398051,"identity":"3ce24f7a-4658-4744-b332-b1b938103f49","order_by":7,"name":"Yu-Chi Fang","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yu-Chi","middleName":"","lastName":"Fang","suffix":""},{"id":635398052,"identity":"1c96ab89-8e2c-49db-9b11-4b391b7ee2c2","order_by":8,"name":"Ruei-Ti Ke","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ruei-Ti","middleName":"","lastName":"Ke","suffix":""},{"id":635398053,"identity":"5a0ae459-048f-456f-8c09-5247270be77b","order_by":9,"name":"Daniel Huang","email":"","orcid":"","institution":"Kaohsiung Chang Gung Memorial Hospital","correspondingAuthor":false,"prefix":"","firstName":"Daniel","middleName":"","lastName":"Huang","suffix":""}],"badges":[],"createdAt":"2026-04-12 16:38:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9395764/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9395764/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108806795,"identity":"586db019-e64e-48ff-9a8c-c06d82b46594","added_by":"auto","created_at":"2026-05-08 15:29:29","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":285822,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9395764/v1/3a78f892-a37e-44d5-94d3-a4d21b87fb2c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Cryoablation vs Thoracoscopic Resection in the Local Management of Pulmonary Metastases Including Primary Lung Cancer with Intrapulmonary Spread","fulltext":[{"header":"Background","content":"\u003cp\u003eThe lungs are a common site of metastasis from various malignancies, particularly those originating from the breast, lung, head and neck, colon, rectum, and liver.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] Although surgical resection remains the standard of care for these patients when feasible,[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] many patients are not considered suitable surgical candidates owing to limited pulmonary function, multiple prior thoracic surgeries, comorbidities, advanced age, or personal refusal of surgery.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIn addition to surgery, several local treatment modalities have recently become available for patients with small non-small-cell lung cancer and oligometastatic diseases. These include stereotactic ablative radiotherapy and percutaneous thermal ablative therapies, such as radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation (CA), and irreversible electroporation,[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] which have been compared in previous studies.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e4\u003c/span\u003e] The optimal treatment strategy should be developed based on tumor location and individual clinical condition.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eImage-guided percutaneous CA offers the distinct advantage of real-time visualization of the ablation zone using computed tomography (CT), characterized by interstitial or consolidative changes or the formation of visible ice. This facilitates effective tumor destruction while minimizing injury to the surrounding normal lung parenchyma.[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR19\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] CA may be more effective than RFA or MWA in certain settings.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eA major advantage of CA over surgical resection is its ability to preserve lung parenchyma and maintain pulmonary function.[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e9\u003c/span\u003e] However, few studies have directly compared the perioperative outcomes between surgical resection and percutaneous CA. Therefore, the present study aimed to compare the perioperative outcomes between these two modalities.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEthical Statement\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental protocol was established in accordance with the ethical guidelines of the Declaration of Helsinki and was approved by the Institutional Review Board of XXXX Hospital (approval number: 202500763B0, 2025/5/23). Given its retrospective design, the requirement for informed consent was waived. This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePatient selection\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe retrospectively reviewed the electronic medical records of patients with pulmonary metastatic tumors who underwent either surgical resection or percutaneous CA between June 2022 and September 2024 at XXXX Hospital. All patients were evaluated by a multidisciplinary team comprising surgeons, thoracic surgeons, oncologists, and radiologists.\u003c/p\u003e\n\u003cp\u003eThe inclusion criteria were age \u0026ge;18 years, confirmed pulmonary metastatic disease, and a history of either lung surgery or percutaneous CA as local treatment. Patients who underwent combined surgeries involving other metastatic sites were excluded owing to the potential for prolonged operative time. A total of 88 patients met the inclusion criteria. Overall, 3 patients were excluded because they underwent combined surgeries, resulting in a final cohort of 85 patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eTreatment Plan\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter confirming that the primary malignancy was under control or that the patient had oligometastatic disease, a multidisciplinary team comprising thoracic surgeons, general surgeons, oncologists, and radiologists conducted a comprehensive evaluation. This included assessments of pulmonary and cardiac function, Eastern Cooperative Oncology Group performance status, and the patient\u0026rsquo;s financial condition. The risks and benefits of both treatment options were thoroughly discussed with patients and their families.\u003c/p\u003e\n\u003cp\u003eThe feasibility of wedge resection was carefully evaluated, particularly for large or centrally located tumors, where achieving an adequate surgical margin could be technically challenging or oncologically insufficient. Anatomical resection, including segmentectomy or lobectomy, was required when wedge resection could not ensure safe surgical margins. The treatment plan was finalized when a consensus was reached between the patient and the multidisciplinary team.\u003c/p\u003e\n\u003cp\u003eChest CT was performed within 4 weeks before treatment to confirm the status of the metastatic lesions. Bilateral pulmonary metastases were treated simultaneously in a single session whenever clinically feasible.\u003c/p\u003e\n\u003cp\u003eFor patients with multiple pulmonary metastases, the treatment goal was to achieve complete resection or ablation of all visible lesions in a single session whenever technically feasible. Staged procedures were considered only when simultaneous treatment of all lesions was not technically possible or carried excessive risk.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eThoracic surgery\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThoracoscopic wedge resection was initially considered for all patients undergoing thoracic surgery. In cases where a safe surgical margin could not be achieved, particularly for large or centrally located tumors, anatomical resection, including thoracoscopic segmentectomy or lobectomy, was performed. Each surgery was performed by one of the five thoracic surgeons. Consistency was maintained across cases in terms of operating room setup, surgical team composition, and instrumentation.\u003c/p\u003e\n\u003cp\u003eFor patients with bilateral pulmonary metastases, resections were performed in a single-stage operation via sequential thoracoscopic approaches rather than staged procedures.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCA procedure\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePercutaneous CA was performed in a hybrid operating room under general anesthesia with single-lumen endotracheal intubation. CA needles (17-gauge; Galil Medical, Inc., Boston Scientific Corporation, Marlborough, MA, USA) were placed under the guidance of a Siemens Artis Zeego cone-beam CT system to ensure that the ice ball fully encompassed the index tumor(s) with an adequate ablative margin.\u003c/p\u003e\n\u003cp\u003eThe number and configuration of the needles were determined based on the distance between the tumor margins and needle placement to achieve optimal coverage. CA typically followed a three-cycle freeze\u0026ndash;thaw protocol, and the procedure was monitored using the Zeego system with cone-beam CT performed at 3- to 5-min intervals to assess the ablation zone. The goal was to ensure that the ice ball completely encompassed the tumor with an adequate margin to achieve effective ablation.[1]\u003c/p\u003e\n\u003cp\u003eFor patients with multiple tumors, intraoperative repositioning, repeated puncture, and resterilization were often required to facilitate accurate needle placement, ensure complete ablation of all target lesions, and minimize the risk of injury to adjacent critical structures.\u003c/p\u003e\n\u003cp\u003eUpon completion of the ablation protocol, a follow-up cone-beam CT scan was performed approximately 10 min later to confirm successful ice ball formation and assess for procedure-related complications such as pneumothorax. If pneumothorax was detected during or after the procedure, thoracostomy was performed. The chest tube size was selected based on the extent of the pneumothorax.\u003c/p\u003e\n\u003cp\u003eAll cryoablation procedures were performed under general anesthesia with single-lumen endotracheal intubation. This approach was chosen because cryoablation sessions are typically prolonged and often require multiple breath-holding cycles. Controlled ventilation allowed for consistent lung expansion during CT scanning and needle placement, ensuring accurate alignment of the puncture trajectory with imaging. In addition, patient repositioning was frequently required to access multiple lesions or avoid critical structures, and maintaining these positions was more feasible under general anesthesia. Finally, in the event of acute complications such as hemothorax, general anesthesia enabled immediate surgical intervention if necessary.\u003c/p\u003e\n\u003cp\u003eSimilarly, in the cryoablation group, patients with bilateral pulmonary metastases underwent single-session procedures, with both lungs treated during the same intervention under CT guidance.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eData collection\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData collected included patient age, sex, primary tumor origin, tumor histology, type of surgery performed (wedge resection, segmentectomy, or lobectomy), history of prior ipsilateral pulmonary surgery, treated side, number of treated tumors, maximum tumor size, presence of postoperative drainage, number of drainage tubes, and maximum drainage tube size (in French units, Fr).\u003c/p\u003e\n\u003cp\u003eThe operative time (in h) was defined as the interval from skin incision (for surgical cases) or initiation of the Zeego system (for CA cases) to patient extubation. The length of hospital stay was defined as the number of days from the procedure (either surgery or CA) to hospital discharge.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStatistical analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eContinuous variables were expressed as mean \u0026plusmn; standard deviation, and categorical variables were presented as frequencies and percentages. Group comparisons of continuous variables (e.g., operation time, length of hospital stay, drainage number, and maximum drainage size) between the CA and thoracic surgery groups were performed using independent sample t-tests. Categorical variables were compared using the chi-squared test or Fisher\u0026apos;s exact test, as appropriate. Statistical significance was set at P \u0026lt; 0.05. All statistical analyses were performed using the SPSS software (version 23.0; IBM Corp., Armonk, NY, USA).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePatient characteristics\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 85 patients with pulmonary metastatic tumors were enrolled. The basic clinical parameters of the patients are summarized in Table 1. The mean age was 61.8 and 65.5, with a nearly equal sex distribution (44 men and 41 women). Among the 85 patients, 70 (82.4%) underwent thoracoscopic pulmonary metastasectomy (thoracic surgery), and 15 (17.6%) underwent percutaneous CA. There were no significant differences in age (P = 0.33) and sex (P = 0.561) between the two groups.\u003c/p\u003e\n\u003cp\u003eCompared with patients who underwent thoracic surgery, those who underwent CA were significantly more likely to have undergone prior ipsilateral lung surgery (66.7% \u003cem\u003evs\u003c/em\u003e. 18.6%, P = 0.000), suggesting that this group had more complex surgical histories. Other factors, including tumor number (\u0026le;3 \u003cem\u003evs\u003c/em\u003e. \u0026gt;3, P = 0.144) and disease laterality (unilateral vs. bilateral, P = 0.088), did not significantly differ between the two groups. However, a higher proportion of patients in the CA group had tumors \u0026gt; 1 cm (80.0% \u003cem\u003evs\u003c/em\u003e. 42.9%, P = 0.009) than in the thoracic surgery group.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePrimary tumor origin\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePrimary tumor origins are summarized in Table 1. The most common source was colorectal cancer, representing 21.4% of the thoracoscopic resection cohort and 46.6% of the cryoablation cohort. Lung cancer with intrapulmonary metastases was also frequent (21.4% and 13.3%, respectively), along with head and neck cancers. Less common categories included genitourinary, hepatobiliary, gynecologic, and breast malignancies. Rare entities such as thymoma and mesothelioma with intrapulmonary spread were grouped as \u0026ldquo;other/rare.\u0026rdquo; This classification underscores the wide oncologic spectrum of patients considered for local pulmonary treatments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eTumor histology\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTumor histologies are summarized in Table 1. Adenocarcinoma was the predominant subtype, comprising nearly half of thoracoscopic resections (47.1%) and the majority of cryoablation cases (60%). Squamous cell carcinoma was the next most common, whereas sarcomas\u0026mdash;including osteosarcoma and liposarcoma\u0026mdash;were less frequent. Other histologies included urothelial carcinoma, melanoma, hepatocellular carcinoma, and adenoid cystic carcinoma, as well as a small number of rare variants. These findings reflect the heterogeneity of pulmonary metastases, which are addressed through surgical and ablative approaches.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e \u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSurgical procedures\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSurgical procedures are summarized in Table 2. Non-anatomical wedge resections accounted for the majority of cases, with single or multiple wedge resections performed in 90% of thoracoscopic resections. A smaller number involved combined resections, such as wedge resection with chest wall or diaphragm resection. Anatomical resections were less frequent, including segmentectomy and lobectomy, which were performed selectively when adequate margins were required. This distribution highlights wedge resection as the dominant strategy in pulmonary metastasectomy, consistent with its balance of oncologic adequacy and parenchymal preservation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePerioperative outcomes\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll perioperative outcomes, including operative time, hospital stay, drainage-related parameters, and procedure-related costs, are summarized in Table 3. Although the mean operation time was longer in the CA group (4.26 \u0026plusmn; 1.90 h) than in the thoracic surgery group (2.22 \u0026plusmn; 1.28 h), the difference did not reach statistical significance (P = 0.123). The length of hospital stay was also similar between groups (CA: 4.00 \u0026plusmn; 1.85 d \u003cem\u003evs\u003c/em\u003e. thoracic surgery: 4.73 \u0026plusmn; 2.65 d, P = 0.307).\u003c/p\u003e\n\u003cp\u003eIn contrast, drainage-related outcomes significantly favored CA. Approximately half of the patients in the CA group (46.0%) were managed without thoracic drainage, compared with only 2.8% in the thoracic surgery group (P = 0.000). Additionally, compared with the thoracic surgery group, both the average number of drains (0.6 \u0026plusmn; 0.63 \u003cem\u003evs\u003c/em\u003e. 1.11 \u0026plusmn; 0.41, P = 0.001) and maximum drain size (7.07 \u0026plusmn; 7.00 Fr \u003cem\u003evs\u003c/em\u003e. 20.92 \u0026plusmn; 2.37 Fr, P = 0.000) were significantly lower in the CA group, indicating a less invasive profile and potentially improved perioperative comfort. The mean procedure-related cost was significantly higher in the cryoablation group compared with thoracoscopic resection (201,933 NTD vs. 53,107 NTD, P \u0026lt; 0.001)\u003c/p\u003e\n\u003cp\u003eTo further account for potential confounding factors, multivariable regression analyses were performed. Logistic regression for drainless management demonstrated that cryoablation remained independently associated with a higher likelihood of avoiding chest drainage (adjusted OR 0.044, 95% CI 0.005\u0026ndash;0.429, P = 0.007). Linear regression models for drainage number and maximum drainage size similarly confirmed that the surgical method was the only significant predictor, whereas age, sex, prior ipsilateral thoracic surgery, and tumor size were not significant contributors. These adjusted results are presented in Supplementary Table 1.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eMinimally invasive local treatments, such as RFA, MWA, and CA, are increasingly used to manage pulmonary metastases. CA, in particular, has gained attention for its ability to preserve surrounding tissue, improve visualization, and reduce procedural pain.[3, 4, 9] These features may make it a viable option for lesions close to critical structures.[4, 9]\u003c/p\u003e\n\u003cp\u003eAlthough some studies have shown that ablation therapies are comparable to surgery in certain settings,[10] direct comparisons between CA and surgical resection are limited. Our study aimed to provide insights into this comparison.\u003c/p\u003e\n\u003cp\u003eIn our cohort, CA procedures tended to take longer than thoracoscopic resection. This may reflect the need for multiple patient repositionings and repeated sterilization steps for accessing lesions in different lung segments. These logistical factors have also been noted in other studies, in which CA times widely varied depending on tumor location and number.[6, 11] Despite the longer procedure time, CA was associated with less frequent use of chest drainage tubes. This is consistent with previous reports suggesting that CA preserves lung parenchyma and reduces the risk of pneumothorax.[9] In our analysis, chest tube insertion could be avoided in approximately half of the CA group, thereby improving postoperative comfort. These findings remained consistent after adjustment for age, sex, prior ipsilateral thoracic surgery, and tumor size, with the surgical method being the only independent predictor of drainage outcomes (Supplementary Table 1).\u003c/p\u003e\n\u003cp\u003eImportantly, no instances of pleural seeding or major complications requiring surgical management (e.g., refractory pneumothorax or empyema) were observed in our cohort. However, previous reports have documented cases of pleural seeding following cryoablation complicated by pneumothorax[12, 13], as well as severe complications necessitating surgical intervention[14]. This suggests that although our results are reassuring, long-term follow-up is necessary to fully evaluate these risks.\u003c/p\u003e\n\u003cp\u003eWhen considering complete clearance of multiple pulmonary metastases in a single session, one limitation of thoracoscopic resection is that very small or deeply seated nodules may be difficult to localize or palpate intraoperatively, potentially preventing complete resection. By contrast, cryoablation under CT guidance can effectively target radiologically visible lesions, even when they are non-palpable. This capability may enhance the likelihood of achieving complete tumor clearance in a single procedure, particularly in patients with sub-centimeter or deep parenchymal nodules.\u003c/p\u003e\n\u003cp\u003eA notable proportion of patients who underwent CA had a history of ipsilateral thoracic surgery. Reoperation in such cases is often technically challenging because of the pleural adhesions. For these patients, CA may offer a less invasive approach that avoids surgical reentry. In addition, CA is typically performed under moderate sedation or general anesthesia, without single-lung ventilation. This may help reduce the risk of ventilator-induced lung injury, particularly in patients with a limited pulmonary reserve. In contrast, thoracoscopic metastasectomy often necessitates the deflation of the operated lung, which can impose physiological stress and increase postoperative pulmonary risk. CA could be a reasonable alternative in patients with reduced cardiopulmonary function or surgical intolerance.[3, 4, 9]\u003c/p\u003e\n\u003cp\u003eAlthough this study focused on the perioperative outcomes, long-term disease control remains a key consideration. Prospective trials have reported encouraging local control rates at 2\u0026ndash;5 years with CA.[1, 6] Therefore, CA is a potential local therapy, particularly in well-selected oligometastasis cases. Future studies should compare long-term outcomes between pulmonary metastasectomy and percutaneous ablation, incorporate patient-reported quality-of-life measures, and further address rare but clinically relevant complications, including pleural dissemination and persistent pleural space problems, to establish optimal patient selection and follow-up protocols.\u003c/p\u003e\n\u003cp\u003eAnother important consideration is cost. Although cryoablation demonstrated favorable perioperative outcomes, its substantially higher procedure-related cost compared with thoracoscopic resection may limit broader adoption. The higher procedure-related cost of cryoablation in our series was largely attributable to device- and equipment-related expenses, as operative time was comparable between the two groups. In Taiwan\u0026rsquo;s healthcare system, thoracoscopic resection is largely reimbursed by the National Health Insurance (NHI), whereas cryoablation consumables are entirely self-funded. Thus, the actual out-of-pocket cost for surgery may be as low as one-tenth of the calculated procedure-related expense, whereas patients undergoing cryoablation bear the full cost. This reimbursement discrepancy limits the generalizability of our cost comparison and underscores the need to interpret financial outcomes within the context of local healthcare systems.\u003c/p\u003e\n\u003cp\u003eThis study has some limitations. This was a retrospective study, and patient selection may have influenced the observed outcomes. The heterogeneity of tumor histology and primary sites limits generalizability. Perioperative complications that may affect recovery and treatment decisions were excluded from the analysis. Long-term outcomes such as progression-free and overall survival were not assessed. Therefore, these aspects should be considered in future studies. Another limitation is the imbalance between the two treatment groups (thoracoscopic resection, n = 70; cryoablation, n = 15), reflecting real-world practice and the limited adoption of cryoablation at our center. Moreover, treatment allocation was non-randomized and influenced by clinical judgment and patient preference, which introduces potential selection bias. Although multivariable adjustment was performed, residual confounding cannot be excluded, and the results should therefore be interpreted with caution. \u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eCA is a less invasive and tubeless alternative to thoracoscopic pulmonary metastasectomy, particularly in patients with a history of thoracic surgery or limited pulmonary reserve. Although the procedure time may be longer, the reduced need for chest tubes and avoidance of single-lung ventilation support the use of CA in selected cases.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental protocol was established in accordance with the ethical guidelines of the Declaration of Helsinki and was approved by the Institutional Review Board of XXXX Hospital (approval number: 202500763B0, 2025/5/23). Given its retrospective design, the requirement for informed consent was waived.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank Editage for providing language editing assistance.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of generative AI and AI-assisted technologies in the writing process\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work, the author(s) used ChatGPT to assist with refining the abstract, conclusion, and discussion; generating the graphical abstract and central picture legend; drafting the central message, ultramini abstract, and perspective statement; and formatting the case report form. The tool was also used to clarify journal-specific formatting requirements and to ensure language consistency throughout the manuscript. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the publication\u0026apos;s content.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ede Ba\u0026egrave;re T, et al. The ECLIPSE Study: Efficacy of cryoablation on metastatic lung tumors with a 5-year follow-up. J Thorac Oncol. 2021;16:1840\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Ba\u0026egrave;re T, et al. Evaluating cryoablation of metastatic lung tumors in patients\u0026ndash;safety and efficacy: The ECLIPSE Trial\u0026ndash;Interim analysis at 1 Year. J Thorac Oncol. 2015;10:1468\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Ba\u0026egrave;re T, et al. Lung ablation: Best practice/results/response assessment/role alongside other ablative therapies. Clin Radiol. 2017;72:657\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrud'homme C, et al. Image-guided lung metastasis ablation: a literature review. Int J Hyperth. 2019;36:37\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhmed A, Littrup P. Percutaneous cryotherapy of the thorax: safety considerations for complex cases. AJR Am J Roentgenol. 2006;186:1703\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCallstrom MR, et al. Multicenter study of metastatic lung tumors targeted by interventional cryoablation evaluation (SOLSTICE). J Thorac Oncol. 2020;15:1200\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang H, et al. Thoracic masses treated with percutaneous cryotherapy: initial experience with more than 200 procedures. Radiology. 2005;235(1):289\u0026ndash;98.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang KQ, Zhang JR, Wei HM. Therapeutic effects of cryoablation, radiofrequency ablation, and microwave coagulation against VX2 liver cancer: a comparative study in rabbits. Nan Fang Yi Ke Da Xue Xue Bao. 2007;27:1431\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVelez A, DeMaio A, Sterman D. Cryoablation and immunity in non-small cell lung cancer: a new era of cryo-immunotherapy. Front Immunol. 2023;14:1203539.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOhmoto K, et al. Comparison of therapeutic effects between radiofrequency ablation and percutaneous microwave coagulation therapy for small hepatocellular carcinomas. J Gastroenterol Hepatol. 2009;24:223\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcDevitt JL, et al. Percutaneous cryoablation for the treatment of primary and metastatic lung tumors: Identification of risk factors for recurrence and major complications. J Vasc Interv Radiol. 2016;27:1371\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamauchi Y, et al. Needle-tract seeding after percutaneous cryoablation for lung metastasis of colorectal cancer. Ann Thorac Surg. 2011;92:e69\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eConners D, Rilling W. Pleural tumor seeding following percutaneous cryoablation of hepatocellular carcinoma. Semin Intervent Radiol. 2011;28:258\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVyas V, Paul M. A case of catastrophic complications following cryoablation of lung cancer. Chest. 2020;158:A1626.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Ba\u0026egrave;re T, et al. The ECLIPSE Study: Efficacy of Cryoablation on Metastatic Lung Tumors With a 5-Year Follow-Up. J Thorac Oncol. 2021;16(11):1840\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Baere T, et al. Evaluating Cryoablation of Metastatic Lung Tumors in Patients\u0026ndash;Safety and Efficacy: The ECLIPSE Trial\u0026ndash;Interim Analysis at 1 Year. J Thorac Oncol. 2015;10(10):1468\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Baere T, et al. Lung ablation: Best practice/results/response assessment/role alongside other ablative therapies. Clin Radiol. 2017;72(8):657\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrud'homme C, et al. Image-guided lung metastasis ablation: a literature review. Int J Hyperth. 2019;36(2):37\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhmed A, Littrup P. Percutaneous cryotherapy of the thorax: safety considerations for complex cases. AJR Am J Roentgenol. 2006;186(6):1703\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCallstrom MR, et al. Multicenter Study of Metastatic Lung Tumors Targeted by Interventional Cryoablation Evaluation (SOLSTICE). J Thorac Oncol. 2020;15(7):1200\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang H, et al. Thoracic masses treated with percutaneous cryotherapy: initial experience with more than 200 procedures. Radiology. 2005;235(1):289\u0026ndash;98.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang KQ, Zhang JR, Wei HM. Therapeutic effects of cryoablation, radiofrequency ablation, and microwave coagulation against VX2 liver cancer: a comparative study in rabbits]. Nan Fang Yi Ke Da Xue Xue Bao. 2007;27(9):1431\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVelez A, DeMaio A, Sterman D. Cryoablation and immunity in non-small cell lung cancer: a new era of cryo-immunotherapy. Front Immunol. 2023;14:1203539.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOhmoto K, et al. Comparison of therapeutic effects between radiofrequency ablation and percutaneous microwave coagulation therapy for small hepatocellular carcinomas. J Gastroenterol Hepatol. 2009;24(2):223\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcDevitt JL, et al. Percutaneous Cryoablation for the Treatment of Primary and Metastatic Lung Tumors: Identification of Risk Factors for Recurrence and Major Complications. J Vasc Interv Radiol. 2016;27(9):1371\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamauchi Y, et al. Needle-tract seeding after percutaneous cryoablation for lung metastasis of colorectal cancer. Ann Thorac Surg. 2011;92(4):e69\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eConners D, Rilling W. Pleural tumor seeding following percutaneous cryoablation of hepatocellular carcinoma. Semin Intervent Radiol. 2011;28(2):258\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVyas V, Paul M. A CASE OF CATASTROPHIC COMPLICATIONS FOLLOWING CRYOABLATION OF LUNG CANCER. Chest. 2020;158(4):A1626.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cdiv class=\"gridtable\"\u003e\n \u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003ePatient characteristics\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eDemographic\u003c/span\u003e\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eThoracoscopic Resection (n\u0026thinsp;=\u0026thinsp;70)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCryoablation (n\u0026thinsp;=\u0026thinsp;15)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eP-Value\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eMean age\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e61.8\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e65.5\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.33\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGender (Male/Female)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e36/34 (1.05)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e8/7 (1.14)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.561\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003ePrimary tumor origin\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eColorectal (colon, rectum, cecum, ileum)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e15 (21.4%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7 (46.6%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\" morerows=\"8\" rowspan=\"9\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.431\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eLung (primary lung cancer with intrapulmonary spread)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e15 (21.4%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2 (13.3%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eHepatobiliary/pancreas (liver, bile duct, pancreas)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e5 (7.1%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eHead \u0026amp; neck (oral cavity, pharynx, larynx, salivary gland)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e12 (17.1)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2 (13.3%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eBreast\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3 (4.2%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1 (6.6%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGynecologic (endometrium, cervix, ovary, vagina)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4 (5.7%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGenitourinary (kidney, bladder, prostate, testis, etc.)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e6 (8.5%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSarcoma (osteosarcoma, liposarcoma, myxofibrosarcoma, etc.)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2 (2.8%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eOthers/rare (thymoma, mesothelioma with intrapulmonary metastasis, thyroid medullary carcinoma, melanoma, etc.)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3 (4.2%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2 (13.3%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eTumor histology (N/percentage)\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eAdenocarcinoma\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e33 (47.1%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e9 (60%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.517\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSquamous cell carcinoma\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e12 (17.1%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1 (6.6%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eOthers\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e25 (35.7%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e5 (33.3%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eDisease characteristics\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eNumber of tumors\u0026thinsp;\u0026lt;\u0026thinsp;3\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003eNumber of tumors\u0026thinsp;\u0026gt;\u0026thinsp;3\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003eLargest tumor\u0026thinsp;\u0026gt;\u0026thinsp;1 cm\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e5 (7.1%)\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003e65 (92.8%)\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003e30 (42.8%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3 (20%)\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003e12 (80%)\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003e12 (80%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.144\u003c/div\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.009\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eUnilateral disease\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e60 (85.7%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10 (66.6%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.088\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eBilateral disease\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10 (14.2%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e5 (33.3%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003ePrior ipsilateral thoracic surgery\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e13 (18.6%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e10 (66.7%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u0026lt;\u0026thinsp;0.001\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003eVATS, video-assisted thoracoscopic surgery\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSurgical procedure classification\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eTotal\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e70\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eNon-anatomical resection (wedge resection)\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSingle wedge resection\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e26 (37.1%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eMultiple wedge resection\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e37 (52.8%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCombined procedures (e.g., wedge with chest wall or diaphragm resection)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2 (2.85%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan type=\"Bold\" class=\"Bold\" name=\"Emphasis\"\u003eAnatomical resection\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSingle segmentectomy\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1 (1.4%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSingle lobectomy\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1 (1.4%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCombined procedure (segmentectomy or lobectomy with wedge resection)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e3 (4.2%)\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eComparison of perioperative outcomes between cryoablation and lung resection\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eParameter\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eThoracic surgery (N\u0026thinsp;=\u0026thinsp;70)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eCryoablation (N\u0026thinsp;=\u0026thinsp;15)\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eP-value\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eOperation time (h)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2.22\u0026thinsp;\u0026plusmn;\u0026thinsp;1.28\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4.26\u0026thinsp;\u0026plusmn;\u0026thinsp;1.90\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.123\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eLength of stay (d)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4.73\u0026thinsp;\u0026plusmn;\u0026thinsp;2.65\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.85\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.307\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eDrainless\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2 (2.8%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7 (46%)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eDrainage number\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e1.114\u0026thinsp;\u0026plusmn;\u0026thinsp;0.408\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.632\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.001\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eMax drainage size (Fr)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e20.92\u0026thinsp;\u0026plusmn;\u0026thinsp;2.37\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e7.07\u0026thinsp;\u0026plusmn;\u0026thinsp;7.00\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eMean procedure-related cost (NTD)\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e53106.771\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e201933.333\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0.000\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Supplementary Table","content":"\u003cp\u003eSupplementary Table 1. Multivariable regression analyses for drainage outcomes\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eOutcome\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eSignificant Factor(s)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eEffect (B / OR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 147px;\"\u003e\n \u003cp\u003eOther Covariates\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eDrainless (binary, logistic regression)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eOperation method (CA vs. VATS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eOR = 0.044 (95% CI: 0.005\u0026ndash;0.429)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 147px;\"\u003e\n \u003cp\u003eAge, sex, prior ipsilateral surgery, tumor size \u0026rarr; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eDrain number (linear regression)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eOperation method (CA vs. VATS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eB = \u0026ndash;0.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 147px;\"\u003e\n \u003cp\u003eAge, prior ipsilateral surgery, tumor size \u0026rarr; NS; sex showed borderline trend (p = 0.056)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eMax drainage size (linear regression)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eOperation method (CA vs. VATS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 111px;\"\u003e\n \u003cp\u003eB = \u0026ndash;14.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 147px;\"\u003e\n \u003cp\u003eAge, sex, prior ipsilateral surgery, tumor size \u0026rarr; NS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-cardiothoracic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jcts","sideBox":"Learn more about [Journal of Cardiothoracic Surgery](http://cardiothoracicsurgery.biomedcentral.com)","snPcode":"13019","submissionUrl":"https://submission.nature.com/new-submission/13019/3","title":"Journal of Cardiothoracic Surgery","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Cryoablation, Minimally invasive treatment, Perioperative outcomes, Pulmonary metastasis, Thoracoscopic resection","lastPublishedDoi":"10.21203/rs.3.rs-9395764/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9395764/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e \u003cp\u003eSurgical resection remains a commonly used local treatment option for selected patients with pulmonary metastases. However, a subset of patients, particularly those with limited pulmonary reserve or prior ipsilateral thoracic surgery, may not tolerate the procedure well. Percutaneous cryoablation is a less invasive option; however, comparisons of perioperative outcomes with those of surgery are limited. We aimed to compare the perioperative outcomes between these two modalities.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eWe retrospectively analyzed 85 patients with metastatic pulmonary tumors treated at a single tertiary center between June 2022 and September 2024. The patients underwent thoracoscopic pulmonary metastasectomy (n\u0026thinsp;=\u0026thinsp;70) or percutaneous cryoablation (n\u0026thinsp;=\u0026thinsp;15). Clinical parameters, including operative time, chest drainage, and length of hospital stay, were compared between the groups.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003ePatients selected for cryoablation had a higher incidence of ipsilateral thoracic surgery (66.7% \u003cem\u003evs\u003c/em\u003e. 18.6%; P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) than those selected for thoracic surgery. Although the average procedure time was longer (4.26 \u003cem\u003evs\u003c/em\u003e. 2.22 h, P\u0026thinsp;=\u0026thinsp;0.123), the need for chest tube placement (46.0% \u003cem\u003evs\u003c/em\u003e. 2.8%, P\u0026thinsp;=\u0026thinsp;0.000) and the number and size of drains were significantly lower (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01) in the cryoablation group versus the thoracic surgery group. The length of hospital stay was similar in both groups.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusions\u003c/b\u003e\u003c/p\u003e \u003cp\u003eIn selected patients, particularly those with previous thoracic interventions or impaired pulmonary function, percutaneous cryoablation may be a less invasive and tubeless alternative to surgery. These findings support its role as a practical local treatment option when surgery is contraindicated or carries increased risk.\u003c/p\u003e","manuscriptTitle":"Cryoablation vs Thoracoscopic Resection in the Local Management of Pulmonary Metastases Including Primary Lung Cancer with Intrapulmonary Spread","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-08 13:47:56","doi":"10.21203/rs.3.rs-9395764/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-05-12T04:48:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"159704155524229241508830286198246867779","date":"2026-04-30T00:30:43+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-29T17:39:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-21T10:18:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-21T10:18:24+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Cardiothoracic Surgery","date":"2026-04-12T16:35:17+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-cardiothoracic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jcts","sideBox":"Learn more about [Journal of Cardiothoracic Surgery](http://cardiothoracicsurgery.biomedcentral.com)","snPcode":"13019","submissionUrl":"https://submission.nature.com/new-submission/13019/3","title":"Journal of Cardiothoracic Surgery","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c931db7d-66b6-49d3-b9ca-3b348e98d571","owner":[],"postedDate":"May 8th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-12T04:48:02+00:00","index":53,"fulltext":""},{"type":"reviewerAgreed","content":"159704155524229241508830286198246867779","date":"2026-04-30T00:30:43+00:00","index":48,"fulltext":""},{"type":"reviewersInvited","content":"40","date":"2026-04-29T17:39:45+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T13:47:56+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-08 13:47:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9395764","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9395764","identity":"rs-9395764","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}