Pathological Complete Response with the 4AC-4THP Regimen in Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis in Vietnam

Pathological Complete Response with the 4AC-4THP Regimen in Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis in Vietnam | 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 Pathological Complete Response with the 4AC-4THP Regimen in Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis in Vietnam Dinh Anh Tran, Le Huy Trinh, Tuan Anh Pham, Ly Linh Tran, Thuy Duong Phung, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6400760/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose To assess the efficacy of the 4AC-4THP neoadjuvant treatment regimen in Vietnamese patients diagnosed with HER2-positive breast cancer. Methods A retrospective analysis of all 50 HER2 positive breast cancer patients received neoadjuvant therapy with 4AC- 4THP in three institutions in northern Vietnam from January 2016 to October 2024. Pathological response was evaluated using Chevallier’s criteria, in which complete pathological response was defined as yT0yN0 or yTisN0. Results Fifty eligible HER2 positive breast cancer patients treated with 4AC- 4THP regimens in a neoadjuvant setting at Hanoi Medical University Hospital, Vietnam National Cancer Hospital and Hanoi Oncology Hospital were included in the analysis. Median age was 41 (range 26–67 years). Of these 50 patients, 41 (82%) were premenopausal, while 9 (18%) were postmenopausal; 21 patients (42%) had hormone receptor-positive. The overall clinical complete response (cCR) rate for both tumors and lymph nodes was 56% (23 out of 50). The total pathological complete response (pCR) rate was 78% (39 out of 50). pCR was achieved in 40 out of 50 patients (80%) for breast tumors and in 32 out of 34 patients (94.1%) for lymph nodes. There was no significant association between pCR rate and age, tumor grade, hormone receptor status, and Ki-67 expression. Conclusion The 4AC-4THP regimen in neoadjuvant treatment for HER2-positive breast cancer has shown high therapeutic efficacy, achieving a pCR rate of 78.0%. HER2-positive breast cancer neoadjuvant treatment 4AC-4THP regimen pCR Figures Figure 1 Introduction Breast cancer (BC) is the most prevalent malignancy among women globally and the leading cause of cancer-related mortality among females. In Vietnam, breast cancer is the most common cancer in females with 24,563 (28.9%) new cases in 2022 and ranking as the fourth leading cause of death (10,003 deaths) in both genders. 1 The HER2-positive breast cancer subtype is often associated with a poor prognosis, aggressive progression, and an increased likelihood of early recurrence. 2 Neoadjuvant systemic therapy has become the standard of care for patients with HER2-positive breast cancer presenting with locally advanced disease (≥ T2) or regional lymph node involvement. Pathological complete response (pCR) is characterized by the complete absence of invasive carcinoma in the resected breast tissue and all evaluated regional lymph nodes following neoadjuvant treatment (ypT0/Tis ypN0). 3 , 4 Achievement of pCR at the time of surgery has been shown to correlate with improved clinical outcomes, particularly in patients with HER2-positive, hormone receptor (HR)-negative breast cancer, as evidenced by the pooled analysis from the CTNeoBC study. Across all subgroups analyzed, pCR was significantly associated with enhanced event-free survival (EFS) (HR 0.48; 95% CI 0.43–0.54) and overall survival (OS) (HR 0.36; 95% CI 0.31–0.42). 5 The integration of trastuzumab into neoadjuvant chemotherapy regimens has been demonstrated to significantly enhance both pathological complete response (pCR) rates and event-free survival (EFS) compared to chemotherapy alone, as illustrated by findings from the NOAH trial. 6 Consistent improvements in pCR outcomes have also been reported in the TECHNO and GeparQuattro studies, where trastuzumab was incorporated into standard chemotherapy protocols. 7 , 8 Pertuzumab exerts its anti-tumor effect by binding to the extracellular domain II of HER2, thereby inhibiting ligand-dependent HER2–HER3 dimerization 9 . This mechanism of action complements that of trastuzumab. The NeoSphere trial reported a pCR rate of approximately 45% in patients treated with pertuzumab plus trastuzumab and docetaxel, compared to 29% in those receiving trastuzumab and docetaxel alone. 10 The combination of pertuzumab with trastuzumab and docetaxel was further investigated in the CLEOPATRA trial, which demonstrated a significant overall survival benefit (56.5 months vs 40.8 months). 11 Based on these findings, dual HER2-blockade with trastuzumab and pertuzumab in combination with standard neoadjuvant chemotherapy has become the established standard of care. 12 Despite these advances, access to dual HER2-targeted therapy (trastuzumab-pertuzumab) remains limited for many HER2-positive breast cancer patients in Vietnam due to various socioeconomic and healthcare-related barriers. A 2024 survey in Vietnam revealed that only 37.5% of patients with HER2 overexpression received trastuzumab for at least one cycle (partially covered by insurance at 60%), and a mere 2.1% were treated with pertuzumab (not covered by insurance). 13 Due to this limitation, there is a paucity of data regarding the efficacy of dual HER2-targeted therapy in the neoadjuvant treatment of breast cancer in Vietnam. Therefore, we conducted this analysis to evaluate the response rate of the 4AC (anthracycline/cyclophosphamide)-4THP (taxane/trastuzumab/pertuzumab) regimen, a commonly used dual HER2-targeted therapy in combination with chemotherapy, in Vietnamese women with HER2-positive breast cancer. Materials and Methods Study design This study is a retrospective analysis off all 50 women diagnosed with HER2-positive breast cancer at stages II or III, who underwent neoadjuvant treatment with AC-THP regimen at three oncology treatment centers in Northern Vietnam from January 2016 to October 2024. Histopathological response evaluation was based on Chevallier’s criteria, in which complete pathological response was defined as yT0yN0 or yTisN0. The study was approved by the Ethics Committee of Hanoi Medical University. Eligible participants and materials We selected patients who met the following inclusion criteria: Age: 18–79 Histopathologically confirmed diagnosis of invasive beast carcinoma by core needle biopsy. Immunohistochemical (IHC) asscesment was perform on pre-treatment core needle biopsy specimens according to the St. Gallen 2013 classification; HER2 positivity was established with a result of 3 + on IHC or 2 + on IHC combined with positive ISH results. TNM staging according to AJCC 8th edition was assessed through clinical examination combined with information from breast ultrasound, mammography, magnetic resonance imaging and other paraclinical evaluations for metastatic assessment Administration of the 4AC-4THP neoadjuvant treatment regimen. Absence of contraindications to anthracycline medications, including significant cardiovascular conditions such as congestive heart failure, myocarditis, and myocardial infarction. Hematological and biochemical indices permitting chemotherapy LEVF ≥ 50%. Availability of comprehensive medical records. Exclusion Criteria: Presence of bilateral breast cancer or a second primary malignancy. Stage IV breast cancer according to the AJCC 8th edition classification. Existence of other significant comorbidities with an imminent risk of mortality. Non-compliance with the prescribed treatment regimen. Regarding the treatment regimen, patients received neoadjuvant therapy based on the 4AC-4THP regimen. The 4AC regimen consisted of Doxorubicin at a dose of 60 mg/m² and Cyclophosphamide at 600 mg/m², administered every 2 weeks (dose-dense) or every 3 weeks with granulocyte colony-stimulating factor support. The 4THP regimen included Trastuzumab at 8 mg/kg for the first cycle and 6 mg/kg from the second cycle, combined with Pertuzumab at 840 mg for the first cycle and 420 mg from the second cycle, along with a taxane (Docetaxel at 75–100 mg/m² every 3 weeks or Paclitaxel at 80 mg/m² on days 1, 8, and 15 of every 3-week cycle, or Paclitaxel at 175 mg/m² every 2 weeks). All patients underwent radical surgery following neoadjuvant treatment, with subsequent adjuvant therapy including HER2-targeted therapy, radiotherapy, and endocrine treatment depending on treatment response, disease stage, and immunohistochemical characteristics. Information was extracted from medical records, including demographic characteristics of the patients (age, menopausal status, comorbidities, obstetric history) and tumor characteristics (location, size, histological classification, tumor grade, immunohistochemical features, disease stage), in addition to clinical response and histopathological response in the breast and lymph nodes. Statistical analysis The data were analyzed using SPSS Statistics for Win-dows, version 26.0 (IBM Corp., Armonk, USA). Chi-square tests, Fisher’s exact tests, and multivariate analyses for pCR rates were conducted using a Cox proportional hazards model. A two-sided p-value of < 0.05 was considered statistically significant. These methods were employed to assess differences in histopathological responses relative to clinical and pathological characteristics. RESULTS Patients and treatment There were a total of 50 patients diagnosed with HER2-positive breast cancer at stages IIA–IIIC who received treatment from January 2016 to February 2025 at Hanoi Medical University Hospital, Vietnam National Cancer Hospital, and Hanoi Oncology Hospital. These patients met the established inclusion criteria and were included in the analysis. The median age of the cohort was 41 years (range, 26–67 years), and the median tumor size was 37.5 mm. Of these 50 patients, 41 (82%) were premenopausal, while 9 (18%) were postmenopausal. Furthermore, 21 patients (42%) exhibited hormone receptor-positive status, and 1 patient’s HER2 status was confirmed via in-situ hybridization (ISH) testing. The characteristics of the study population are summarized in Table 1 . Table 1 Patient Demographics Characteristics Number (n = 50) Percentage (%) Age < 40 20 40.0 \(\:\ge\:\) 40 30 60.0 Menopausal status Menopausal 9 18.0 Pre-Menopausal 41 82.0 Tumor stage cT1 2 4.0 cT2 34 68.0 cT3 10 20.0 cT4 4 8.0 Lymh node stage cN0 16 32.0 cN1 17 34.0 cN2 12 24.0 cN3 5 10.0 Primary Stage IIA 16 32.0 IIB 12 24.0 IIIA 14 28.0 IIIB 3 6.0 IIIC 5 10.0 Histopathology Invasive breast carcinoma – NST 39 78.0 Other invasive breast carcinomas 11 22.0 Tumor grade 2 33 66.0 3 17 34.0 Hormon Receptor Status Positive (ER and/or PR positive) 21 42.0 Negative 29 58.0 HER2 status IHC (+++) 49 98.0 IHC (++) – Dual-ISH (+) 1 2.0 Ki-67 < 20% 2 4.0 ≥ 20% 48 96.0 AC regimen AC dose-dense (2-week) 46 92.0 AC 3-week 4 8.0 THP regimen Docetaxel – HP 25 50.0 Paclitaxel weekly – HP 7 14.0 Paclitaxel 2-week – HP 18 36.0 Type of Surgery MRM 47 94.0 Conservative 3 6.0 Table 2 Pathological Response by related factors Related factors pCR No. (%) Multivariate analysis (*) p HR Age < 40 18 (90.0) 0.105 1.00 (reference) 0.185 (0.024–1.427) \(\:\ge\:\) 40 21(70.0) Tumor Stage cT1 2 (100.0) 0.081 1.00 (reference) 5.695 (0.806–40.225) cT2 26 (76.5) cT3 7 (70.0) cT4 4 (100.0) Lymph Node Stage cN0 13 (81.3) 0.167 1.00 (reference) 9.024 (0.397-205.008) cN1 12 (70.6) cN2 10 (83.3) cN3 4 (80.0) Primary Stage IIA 15 (93.4) 0.110 1.00 (reference) 0.112 (0.008–1.647) IIB 6 (50.0) IIIA 11(78.6) IIIB 3 (100.0) IIIC 4 (80.0) Tumor Grade 2 28 (84.8) 0.397 1.00 (reference) 0.503 (0.102–2.470) 3 11 (64.7) Hormon Receptor Status Positive (ER and/or PR positive) 24 (82.3) 0.140 1.00 (reference) 0.258 (0.043–1.561) Negative 15 (71.4) Ki-67 < 20% 2 (100.0) 1.000 1.00 (reference) - ≥ 20% 37 (77.1) AC regimen AC dose-dense (2-week) 36 (78.3) 0.890 1.00 (reference) 0.822 (0.051–13.248) AC 3-week 3 (75.0) THP regimen Docetaxel – HP 20 (80.0) 0.333 1.00 (reference) 0.640 (0.259–1.579) Paclitaxel weekly – HP 5 (71.4) Paclitaxel 2-week – HP 14 (77.8) *Wald Test from multivariate Cox regression (backward selection approach) No statistically significant differences were observed in the rates of total pathological complete response (tpCR) when multivariate analyzing the association with factors such as age, tumor stage, lymph node stage, disease stage, tumor histopathology, tumor grade, Ki-67 index, hormone receptor status, and treatment regimen (p > 0.05). Discussion The rate of pathological complete response (pCR) is often a primary endpoint in neoadjuvant breast cancer treatment studies. Trials have indicated that achieving pCR is associated with decreased rates of recurrence and mortality. 14 The combination of chemotherapy with trastuzumab and pertuzumab significantly improves pCR rates in neoadjuvant treatment settings. 12 In the present study, the total pCR rate was reached at 78.0%, with pCR rates for breast tumors and lymph nodes reported at 80.0% and 94.1%, respectively. These results are significantly higher than those from the NEOSPHERE study. In the NEOSPHERE trial, the study population was stratified into four treatment groups, which included trastuzumab combined with docetaxel, pertuzumab combined with trastuzumab and docetaxel, trastuzumab combined with pertuzumab, and docetaxel combined with pertuzumab. The primary objective of the NEOSPHERE study was to evaluate the overall histopathological response at the time of surgical intervention. Results indicated that the group treated with the neoadjuvant regimen of docetaxel combined with trastuzumab and pertuzumab achieved a complete histopathological response in breast tumors (bpCR) of 45.8% and an overall total pathological complete response (tpCR) for both breast and lymph nodes of 39.3%, which was statistically significant compared to the other groups; however, these rates were lower than those found in the current study. It is hypothesized that the lower pCR rates observed in the NEOSPHERE study may be partially attributed to the specific chemotherapy regimen utilized, as their protocol employed docetaxel as a single-agent therapy. 10 In practice, combination therapies involving HER2-targeted agents such as ACTH(P) or TCH(P) are generally associated with higher response rates. Consequently, to achieve higher response rates, the AC-THP regimen was selected, which is also incorporated into several guidelines for neoadjuvant treatment of HER2-positive breast cancer. Another study, the TRYPHAENA trial, reported pCR rates ranging from 54.7% to 63.6% across treatment groups, with the highest response rate observed in the TCHP group. While the primary objective of the TRYPHAENA study was not to evaluate pCR, its secondary outcomes yielded pCR results in the TCHP group that were closely aligned with the findings of the current study, despite differences in the chemotherapy regimens utilized. 15 Thus, the AC-THP regimen demonstrates efficacy comparable to that of larger international studies. Our results are higher than those reported by Phùng Thị Huyền (2020), who found a pCR rate of 64.1% (n=39 patients) for the ACTH or TCH regimen. 16 Furthermore, Phùng Thị Huyền (2021) published findings indicating a pCR rate of 80% with the ACTHP and TCHP regimens among 20 patients, which closely aligns with the results of our study. 17 These findings, along with data from other studies, suggest that the addition of pertuzumab to chemotherapy regimens combined with trastuzumab enhances the likelihood of achieving pCR in HER2-positive breast cancer. Numerous studies have sought to identify predictive factors for pCR among the studied populations. The TECHNO study found no significant differences in pCR rates when comparing variables such as age (<40; ≥40), histological type, tumor grade, tumor stage, lymph node status, and hormone receptor status. 7 Conversely, the Gepar Quattro study reported a higher pCR rate in the hormone receptor-negative group (43.5%), while the hormone receptor-positive group achieved only 23.4% (p < 0.001). 8 The NOAH study noted significant differences in pCR rates between stage II (75%) and stage III (40%) with p = 0.03. 6 After analyzing the pCR rates concerning factors including age, tumor stage (T), lymph node stage (N), overall clinical stage, tumor grade, hormone receptor status, Ki-67 index, and treatment regimen through Table 2, the results of the present study are consistent with the TECHNO study, as there were no significant correlations between the investigated factors and pCR rates. 7 Conclusion The 4AC-4THP regimen in neoadjuvant treatment for HER2-positive breast cancer has shown high therapeutic efficacy, achieving a pathological complete response (pCR) rate of 78.0%. Based on these findings, it is imperative to undertake additional research to investigate the survival benefit associated with this treatment protocol in HER2 postive breast cancer patients. Declarations Acknowledgements We would like to express their sincere gratitude to colleagues at Hanoi Medical University Hospital, the Vietnam National Cancer Hospital, and Hanoi Oncology Hospital for their meaningful support and assistance throughout the study. Special thanks are extended to Associate Professor Huy Le Trinh, whose guidance and mentorship were invaluable during the research process. Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Data availability The datasets generated during and/or analysed during the current study are not publicly available but are available from the corresponding author on reasonable request. Authors' contributions All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Dinh Anh Tran. The first draft of the manuscript was written by Dinh Anh Tran, and all authors provided comments on previous versions. All authors read and approved the final manuscript. Conflict of interest The authors declare that they have no conficts of interest or fnancial ties to disclose with the contents of this article. Ethics approval The study complied with the 1964 Helsinki Declaration and was approved by the Ethics Committee of Hanoi Medical University (IRB-VN 01001), along with the ethical approval certificate number 934/GCN-HĐĐĐNCYSH-ĐHYHN . All participants were informed about the aims of the study and provided written informed consent prior to participation. Consent to Publish declaration: Not applicable. Affiliation Aff1 Hanoi, Vietnam. Aff2 Hanoi, Vietnam. Aff3 Hanoi, Vietnam. Aff4 Hanoi, Vietnam. Clinical Trial Number not applicable. References Cancer Today. 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J Clin Oncol Off J Am Soc Clin Oncol . 2022;40(23):2612-2635. doi:10.1200/JCO.22.00519 Hoang TH, Thi HTP. 15P HER2-positive breast cancer in a low-middle income country (LMIC): Lack of pathology capability and the urgent need for targeted treatment. Ann Oncol . 2024;35:S1410. doi:10.1016/j.annonc.2024.10.035 Davey MG, Browne F, Miller N, Lowery AJ, Kerin MJ. Pathological complete response as a surrogate to improved survival in human epidermal growth factor receptor-2-positive breast cancer: systematic review and meta-analysis. BJS Open . 2022;6(3):zrac028. doi:10.1093/bjsopen/zrac028 Schneeweiss A, Chia S, Hickish T, et al. Long-term efficacy analysis of the randomised, phase II TRYPHAENA cardiac safety study: Evaluating pertuzumab and trastuzumab plus standard neoadjuvant anthracycline-containing and anthracycline-free chemotherapy regimens in patients with HER2-positive early breast cancer. Eur J Cancer Oxf Engl 1990 . 2018;89:27-35. doi:10.1016/j.ejca.2017.10.021 Phung HT, Nguyen HT, Nguyen TV, Nguyen TV, Dinh LAT, Nguyen CV. Pathological Complete Response with Neoadjuvant Trastuzumab Combined with Chemotherapy in HER2 Positive Breast Cancer: A Single Institution Retrospective Analysis from Vietnam. Breast Cancer Dove Med Press . 2020;12:117-122. doi:10.2147/BCTT.S268369 Phùng Thị Huyền. KẾT QUẢ ĐIỀU TRỊ BỔ TRỢ TRƯỚC PHÁC ĐỒ HÓA CHẤT KẾT HỢP TRASTUZUMAB VÀ PERTUZUMAB TRÊN UNG THƯ VÚ CÓ HER2-NEU DƯƠNG TÍNH | Tạp chí Y học Việt Nam. January 12, 2022. https://tapchiyhocvietnam.vn/index.php/vmj/article/view/1761 Additional Declarations No competing interests reported. Supplementary Files DataforFig1.xlsx Cite Share Download PDF Status: Posted Version 1 posted 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. 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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-6400760","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":457902435,"identity":"01025f4a-7d04-4f68-be75-48c2b2b2a3ea","order_by":0,"name":"Dinh Anh Tran","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9ElEQVRIiWNgGAWjYLACHgOGBCDJ+PBDBZDHzNyAXzWSFmZjiTMgLYzEaGEAa2GT4G0DcQlosZc+/OzBm4I7efyze49JSM6rjeZvB2r5UbENty18aeaGcwyeFUvcOZdsUbjteO6Mw4wNjD1nbuPWwsNgJs1jcDix4UaO4Q3JbcdyG4BamBnb8Glh/wbWMv9GjoEE75xjufMJa+GB2LLhRo6RBG9DTe4GglrO8JRJzgFq2Xgjx9hY4tiB3I1ALQfx+YW9h32bxJs/hxPnAf3y8ENNXe6884cPPvhRgVsLOjgMJg8QrR4I6khRPApGwSgYBSMEAABA7VrQQyRt+QAAAABJRU5ErkJggg==","orcid":"","institution":"Hanoi Medical University","correspondingAuthor":true,"prefix":"","firstName":"Dinh","middleName":"Anh","lastName":"Tran","suffix":""},{"id":457902436,"identity":"4dd943a5-2a9c-4e55-ab2b-d63d9075a901","order_by":1,"name":"Le Huy Trinh","email":"","orcid":"","institution":"Hanoi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Le","middleName":"Huy","lastName":"Trinh","suffix":""},{"id":457902437,"identity":"e897617d-688c-4c67-b660-e48927cf75eb","order_by":2,"name":"Tuan Anh Pham","email":"","orcid":"","institution":"Vietnam National Cancer Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tuan","middleName":"Anh","lastName":"Pham","suffix":""},{"id":457902438,"identity":"6fae1914-d431-4d43-8cb3-8f2c07085e44","order_by":3,"name":"Ly Linh Tran","email":"","orcid":"","institution":"Hanoi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ly","middleName":"Linh","lastName":"Tran","suffix":""},{"id":457902439,"identity":"d5e8a3c0-0e5a-4bfa-9001-ed48ff167189","order_by":4,"name":"Thuy Duong Phung","email":"","orcid":"","institution":"Hanoi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Thuy","middleName":"Duong","lastName":"Phung","suffix":""},{"id":457902440,"identity":"f27a62a5-dd5f-4114-8a9c-3b2b5462738b","order_by":5,"name":"Thi Thu Hang Nguyen","email":"","orcid":"","institution":"Hanoi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Thi","middleName":"Thu Hang","lastName":"Nguyen","suffix":""},{"id":457902441,"identity":"c1576cc5-32c9-4fa9-97de-4eaf3e0b01d9","order_by":6,"name":"Thi Hoai Hoang","email":"","orcid":"","institution":"Vietnam National Cancer Hospital","correspondingAuthor":false,"prefix":"","firstName":"Thi","middleName":"Hoai","lastName":"Hoang","suffix":""},{"id":457902442,"identity":"cb98d956-d4a2-4fa0-9688-ac200c8842c7","order_by":7,"name":"Thi Thao Ninh","email":"","orcid":"","institution":"Hanoi Oncology Hospital","correspondingAuthor":false,"prefix":"","firstName":"Thi","middleName":"Thao","lastName":"Ninh","suffix":""},{"id":457902443,"identity":"555e76c0-f78c-4cd2-904f-7a556b2fc2ee","order_by":8,"name":"Thi Thu Hoai Bui","email":"","orcid":"","institution":"Vietnam National Cancer Hospital","correspondingAuthor":false,"prefix":"","firstName":"Thi","middleName":"Thu Hoai","lastName":"Bui","suffix":""},{"id":457902444,"identity":"5b956a72-6aca-47b6-b160-8884dc6b3f1e","order_by":9,"name":"Huu Thang Nguyen","email":"","orcid":"","institution":"Vietnam National Cancer Hospital","correspondingAuthor":false,"prefix":"","firstName":"Huu","middleName":"Thang","lastName":"Nguyen","suffix":""}],"badges":[],"createdAt":"2025-04-08 08:08:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6400760/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6400760/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83291941,"identity":"dffb369b-87a5-4433-9113-22bc23d20854","added_by":"auto","created_at":"2025-05-22 13:14:31","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":31866,"visible":true,"origin":"","legend":"\u003cp\u003eClinical and Pathological Response\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations\u003c/strong\u003e: CR, complete response; PR, partial response; SD, stable disease.\u003c/p\u003e","description":"","filename":"Fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-6400760/v1/f444b0813c74a8a1187dad3d.png"},{"id":87933644,"identity":"7b520dc1-88f5-453f-927d-78251420de2b","added_by":"auto","created_at":"2025-07-30 14:02:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":831482,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6400760/v1/9f9b482b-71fc-431d-adde-e986bdfc2304.pdf"},{"id":83293032,"identity":"7514f934-8f98-45ee-96ed-2a60d0aa8818","added_by":"auto","created_at":"2025-05-22 13:22:31","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":15526,"visible":true,"origin":"","legend":"","description":"","filename":"DataforFig1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-6400760/v1/c3b0d81b3019d52bd6cc723b.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Pathological Complete Response with the 4AC-4THP Regimen in Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis in Vietnam","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBreast cancer (BC) is the most prevalent malignancy among women globally and the leading cause of cancer-related mortality among females. In Vietnam, breast cancer is the most common cancer in females with 24,563 (28.9%) new cases in 2022 and ranking as the fourth leading cause of death (10,003 deaths) in both genders.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003eThe HER2-positive breast cancer subtype is often associated with a poor prognosis, aggressive progression, and an increased likelihood of early recurrence.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eNeoadjuvant systemic therapy has become the standard of care for patients with HER2-positive breast cancer presenting with locally advanced disease (\u0026ge;\u0026thinsp;T2) or regional lymph node involvement. Pathological complete response (pCR) is characterized by the complete absence of invasive carcinoma in the resected breast tissue and all evaluated regional lymph nodes following neoadjuvant treatment (ypT0/Tis ypN0).\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e Achievement of pCR at the time of surgery has been shown to correlate with improved clinical outcomes, particularly in patients with HER2-positive, hormone receptor (HR)-negative breast cancer, as evidenced by the pooled analysis from the CTNeoBC study. Across all subgroups analyzed, pCR was significantly associated with enhanced event-free survival (EFS) (HR 0.48; 95% CI 0.43\u0026ndash;0.54) and overall survival (OS) (HR 0.36; 95% CI 0.31\u0026ndash;0.42).\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe integration of trastuzumab into neoadjuvant chemotherapy regimens has been demonstrated to significantly enhance both pathological complete response (pCR) rates and event-free survival (EFS) compared to chemotherapy alone, as illustrated by findings from the NOAH trial.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e Consistent improvements in pCR outcomes have also been reported in the TECHNO and GeparQuattro studies, where trastuzumab was incorporated into standard chemotherapy protocols.\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003ePertuzumab exerts its anti-tumor effect by binding to the extracellular domain II of HER2, thereby inhibiting ligand-dependent HER2\u0026ndash;HER3 dimerization\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. This mechanism of action complements that of trastuzumab. The NeoSphere trial reported a pCR rate of approximately 45% in patients treated with pertuzumab plus trastuzumab and docetaxel, compared to 29% in those receiving trastuzumab and docetaxel alone.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e The combination of pertuzumab with trastuzumab and docetaxel was further investigated in the CLEOPATRA trial, which demonstrated a significant overall survival benefit (56.5 months vs 40.8 months).\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e Based on these findings, dual HER2-blockade with trastuzumab and pertuzumab in combination with standard neoadjuvant chemotherapy has become the established standard of care.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eDespite these advances, access to dual HER2-targeted therapy (trastuzumab-pertuzumab) remains limited for many HER2-positive breast cancer patients in Vietnam due to various socioeconomic and healthcare-related barriers. A 2024 survey in Vietnam revealed that only 37.5% of patients with HER2 overexpression received trastuzumab for at least one cycle (partially covered by insurance at 60%), and a mere 2.1% were treated with pertuzumab (not covered by insurance).\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e Due to this limitation, there is a paucity of data regarding the efficacy of dual HER2-targeted therapy in the neoadjuvant treatment of breast cancer in Vietnam. Therefore, we conducted this analysis to evaluate the response rate of the 4AC (anthracycline/cyclophosphamide)-4THP (taxane/trastuzumab/pertuzumab) regimen, a commonly used dual HER2-targeted therapy in combination with chemotherapy, in Vietnamese women with HER2-positive breast cancer.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design\u003c/h2\u003e \u003cp\u003eThis study is a retrospective analysis off all 50 women diagnosed with HER2-positive breast cancer at stages II or III, who underwent neoadjuvant treatment with AC-THP regimen at three oncology treatment centers in Northern Vietnam from January 2016 to October 2024. Histopathological response evaluation was based on Chevallier\u0026rsquo;s criteria, in which complete pathological response was defined as yT0yN0 or yTisN0. The study was approved by the Ethics Committee of Hanoi Medical University.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEligible participants and materials\u003c/h3\u003e\n\u003cp\u003eWe selected patients who met the following inclusion criteria:\u003c/p\u003e \u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eAge: 18\u0026ndash;79\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHistopathologically confirmed diagnosis of invasive beast carcinoma by core needle biopsy.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e Immunohistochemical (IHC) asscesment was perform on pre-treatment core needle biopsy specimens according to the St. Gallen 2013 classification; HER2 positivity was established with a result of 3\u0026thinsp;+\u0026thinsp;on IHC or 2\u0026thinsp;+\u0026thinsp;on IHC combined with positive ISH results.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eTNM staging according to AJCC 8th edition was assessed through clinical examination combined with information from breast ultrasound, mammography, magnetic resonance imaging and other paraclinical evaluations for metastatic assessment\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eAdministration of the 4AC-4THP neoadjuvant treatment regimen.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eAbsence of contraindications to anthracycline medications, including significant cardiovascular conditions such as congestive heart failure, myocarditis, and myocardial infarction.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHematological and biochemical indices permitting chemotherapy\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eLEVF\u0026thinsp;\u0026ge;\u0026thinsp;50%.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eAvailability of comprehensive medical records.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e \u003cp\u003eExclusion Criteria:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003ePresence of bilateral breast cancer or a second primary malignancy.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eStage IV breast cancer according to the AJCC 8th edition classification.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eExistence of other significant comorbidities with an imminent risk of mortality.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eNon-compliance with the prescribed treatment regimen.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eRegarding the treatment regimen, patients received neoadjuvant therapy based on the 4AC-4THP regimen. The 4AC regimen consisted of Doxorubicin at a dose of 60 mg/m\u0026sup2; and Cyclophosphamide at 600 mg/m\u0026sup2;, administered every 2 weeks (dose-dense) or every 3 weeks with granulocyte colony-stimulating factor support. The 4THP regimen included Trastuzumab at 8 mg/kg for the first cycle and 6 mg/kg from the second cycle, combined with Pertuzumab at 840 mg for the first cycle and 420 mg from the second cycle, along with a taxane (Docetaxel at 75\u0026ndash;100 mg/m\u0026sup2; every 3 weeks or Paclitaxel at 80 mg/m\u0026sup2; on days 1, 8, and 15 of every 3-week cycle, or Paclitaxel at 175 mg/m\u0026sup2; every 2 weeks). All patients underwent radical surgery following neoadjuvant treatment, with subsequent adjuvant therapy including HER2-targeted therapy, radiotherapy, and endocrine treatment depending on treatment response, disease stage, and immunohistochemical characteristics.\u003c/p\u003e \u003cp\u003eInformation was extracted from medical records, including demographic characteristics of the patients (age, menopausal status, comorbidities, obstetric history) and tumor characteristics (location, size, histological classification, tumor grade, immunohistochemical features, disease stage), in addition to clinical response and histopathological response in the breast and lymph nodes.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe data were analyzed using SPSS Statistics for Win-dows, version 26.0 (IBM Corp., Armonk, USA). Chi-square tests, Fisher\u0026rsquo;s exact tests, and multivariate analyses for pCR rates were conducted using a Cox proportional hazards model. A two-sided p-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant. These methods were employed to assess differences in histopathological responses relative to clinical and pathological characteristics.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003ePatients and treatment\u003c/h2\u003e \u003cp\u003eThere were a total of 50 patients diagnosed with HER2-positive breast cancer at stages IIA\u0026ndash;IIIC who received treatment from January 2016 to February 2025 at Hanoi Medical University Hospital, Vietnam National Cancer Hospital, and Hanoi Oncology Hospital. These patients met the established inclusion criteria and were included in the analysis. The median age of the cohort was 41 years (range, 26\u0026ndash;67 years), and the median tumor size was 37.5 mm. Of these 50 patients, 41 (82%) were premenopausal, while 9 (18%) were postmenopausal. Furthermore, 21 patients (42%) exhibited hormone receptor-positive status, and 1 patient\u0026rsquo;s HER2 status was confirmed via in-situ hybridization (ISH) testing. The characteristics of the study population are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePatient Demographics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNumber (n\u0026thinsp;=\u0026thinsp;50)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePercentage (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e40.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\ge\\:\\)\u003c/span\u003e\u003c/span\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eMenopausal status\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMenopausal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e18.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePre-Menopausal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e82.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003eTumor stage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e68.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e20.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003eLymh node stage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e32.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e34.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e24.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e\u003cb\u003ePrimary Stage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e32.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e24.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e28.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIIB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIIC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eHistopathology\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInvasive breast carcinoma \u0026ndash; NST\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e78.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOther invasive breast carcinomas\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eTumor grade\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e66.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e34.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eHormon Receptor Status\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePositive (ER and/or PR positive)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e42.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e58.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eHER2 status\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIHC (+++)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e98.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIHC (++) \u0026ndash; Dual-ISH (+)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eKi-67\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;20%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;20%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e96.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eAC regimen\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAC dose-dense (2-week)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e92.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAC 3-week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eTHP regimen\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDocetaxel \u0026ndash; HP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e50.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePaclitaxel weekly \u0026ndash; HP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePaclitaxel 2-week \u0026ndash; HP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e36.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eType of Surgery\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMRM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e94.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eConservative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePathological Response by related factors\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" morerows=\"1\" nameend=\"c2\" namest=\"c1\" rowspan=\"2\"\u003e \u003cp\u003eRelated factors\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003epCR No. (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eMultivariate analysis (*)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHR\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (90.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.105\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e0.185 (0.024\u0026ndash;1.427)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\ge\\:\\)\u003c/span\u003e\u003c/span\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21(70.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003eTumor Stage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (100.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.081\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e5.695 (0.806\u0026ndash;40.225)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26 (76.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (70.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecT4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (100.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003eLymph Node Stage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (81.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.167\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e9.024 (0.397-205.008)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (70.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (83.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ecN3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (80.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e\u003cb\u003ePrimary Stage\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 (93.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e0.110\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e0.112 (0.008\u0026ndash;1.647)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (50.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIIA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11(78.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIIB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (100.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIIIC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (80.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eTumor Grade\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28 (84.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.397\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e0.503 (0.102\u0026ndash;2.470)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (64.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eHormon Receptor Status\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePositive (ER and/or PR positive)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24 (82.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.140\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e0.258 (0.043\u0026ndash;1.561)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNegative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15 (71.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eKi-67\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;20%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (100.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;20%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e37 (77.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eAC regimen\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAC dose-dense (2-week)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36 (78.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.890\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e0.822 (0.051\u0026ndash;13.248)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAC 3-week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (75.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003eTHP regimen\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDocetaxel \u0026ndash; HP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20 (80.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.333\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e1.00 (reference)\u003c/p\u003e \u003cp\u003e0.640 (0.259\u0026ndash;1.579)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePaclitaxel weekly \u0026ndash; HP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (71.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePaclitaxel 2-week \u0026ndash; HP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (77.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*Wald Test from multivariate Cox regression (backward selection approach)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e\u003c/table\u003e\u003cp\u003eNo statistically significant differences were observed in the rates of total pathological complete response (tpCR) when multivariate analyzing the association with factors such as age, tumor stage, lymph node stage, disease stage, tumor histopathology, tumor grade, Ki-67 index, hormone receptor status, and treatment regimen (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe rate of pathological complete response (pCR) is often a primary endpoint in neoadjuvant breast cancer treatment studies. Trials have indicated that achieving pCR is associated with decreased rates of recurrence and mortality.\u003csup\u003e14\u003c/sup\u003e The combination of chemotherapy with trastuzumab and pertuzumab significantly improves pCR rates in neoadjuvant treatment settings.\u003csup\u003e12\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eIn the present study, the total pCR rate was reached at 78.0%, with pCR rates for breast tumors and lymph nodes reported at 80.0% and 94.1%, respectively. These results are significantly higher than those from the NEOSPHERE study. In the NEOSPHERE trial, the study population was stratified into four treatment groups, which included trastuzumab combined with docetaxel, pertuzumab combined with trastuzumab and docetaxel, trastuzumab combined with pertuzumab, and docetaxel combined with pertuzumab. The primary objective of the NEOSPHERE study was to evaluate the overall histopathological response at the time of surgical intervention. Results indicated that the group treated with the neoadjuvant regimen of docetaxel combined with trastuzumab and pertuzumab achieved a complete histopathological response in breast tumors (bpCR) of 45.8% and an overall total pathological complete response (tpCR) for both breast and lymph nodes of 39.3%, which was statistically significant compared to the other groups; however, these rates were lower than those found in the current study. It is hypothesized that the lower pCR rates observed in the NEOSPHERE study may be partially attributed to the specific chemotherapy regimen utilized, as their protocol employed docetaxel as a single-agent therapy.\u003csup\u003e10\u003c/sup\u003e In practice, combination therapies involving HER2-targeted agents such as ACTH(P) or TCH(P) are generally associated with higher response rates. Consequently, to achieve higher response rates, the AC-THP regimen was selected, which is also incorporated into several guidelines for neoadjuvant treatment of HER2-positive breast cancer.\u003c/p\u003e\n\u003cp\u003eAnother study, the TRYPHAENA trial, reported pCR rates ranging from 54.7% to 63.6% across treatment groups, with the highest response rate observed in the TCHP group. While the primary objective of the TRYPHAENA study was not to evaluate pCR, its secondary outcomes yielded pCR results in the TCHP group that were closely aligned with the findings of the current study, despite differences in the chemotherapy regimens utilized.\u003csup\u003e15\u003c/sup\u003e Thus, the AC-THP regimen demonstrates efficacy comparable to that of larger international studies. Our results are higher than those reported by Ph\u0026ugrave;ng Thị Huyền (2020), who found a pCR rate of 64.1% (n=39 patients) for the ACTH or TCH regimen.\u003csup\u003e16\u003c/sup\u003e Furthermore, Ph\u0026ugrave;ng Thị Huyền (2021) published findings indicating a pCR rate of 80% with the ACTHP and TCHP regimens among 20 patients, which closely aligns with the results of our study.\u003csup\u003e17\u003c/sup\u003e These findings, along with data from other studies, suggest that the addition of pertuzumab to chemotherapy regimens combined with trastuzumab enhances the likelihood of achieving pCR in HER2-positive breast cancer.\u003c/p\u003e\n\u003cp\u003eNumerous studies have sought to identify predictive factors for pCR among the studied populations. The TECHNO study found no significant differences in pCR rates when comparing variables such as age (\u0026lt;40; \u0026ge;40), histological type, tumor grade, tumor stage, lymph node status, and hormone receptor status.\u003csup\u003e7\u003c/sup\u003e Conversely, the Gepar Quattro study reported a higher pCR rate in the hormone receptor-negative group (43.5%), while the hormone receptor-positive group achieved only 23.4% (p \u0026lt; 0.001).\u003csup\u003e8\u003c/sup\u003e The NOAH study noted significant differences in pCR rates between stage II (75%) and stage III (40%) with p = 0.03.\u003csup\u003e6\u003c/sup\u003e After analyzing the pCR rates concerning factors including age, tumor stage (T), lymph node stage (N), overall clinical stage, tumor grade, hormone receptor status, Ki-67 index, and treatment regimen through Table 2, the results of the present study are consistent with the TECHNO study, as there were no significant correlations between the investigated factors and pCR rates.\u003csup\u003e7\u003c/sup\u003e\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe 4AC-4THP regimen in neoadjuvant treatment for HER2-positive breast cancer has shown high therapeutic efficacy, achieving a pathological complete response (pCR) rate of 78.0%. Based on these findings, it is imperative to undertake additional research to investigate the survival benefit associated with this treatment protocol in HER2 postive breast cancer patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to express their sincere gratitude to colleagues at Hanoi Medical University Hospital, the Vietnam National Cancer Hospital, and Hanoi Oncology Hospital for their meaningful support and assistance throughout the study. Special thanks are extended to Associate Professor Huy Le Trinh, whose guidance and mentorship were invaluable during the research process.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003eThe datasets generated during and/or analysed during the current study are not publicly available but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eAll authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Dinh Anh Tran. The first draft of the manuscript was written by Dinh Anh Tran, and all authors provided comments on previous versions. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no conficts of interest or fnancial ties to disclose with the contents of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval\u0026nbsp;\u003c/strong\u003eThe study complied with the\u0026nbsp;1964 Helsinki Declaration\u0026nbsp;and was approved by the Ethics Committee of Hanoi Medical University (IRB-VN\u0026nbsp;01001), along with the ethical approval certificate number 934/GCN-HĐĐĐNCYSH-ĐHYHN\u003cstrong\u003e.\u0026nbsp;\u003c/strong\u003eAll participants were informed about the aims of the study and provided written informed consent prior to participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish declaration:\u003c/strong\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAffiliation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAff1\u0026nbsp;\u003c/strong\u003eHanoi, Vietnam.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAff2\u0026nbsp;\u003c/strong\u003eHanoi, Vietnam.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAff3\u0026nbsp;\u003c/strong\u003eHanoi, Vietnam.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAff4\u0026nbsp;\u003c/strong\u003eHanoi, Vietnam.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial Number\u003c/strong\u003e\u0026nbsp; not applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eCancer Today. Accessed April 5, 2025. https://gco.iarc.who.int/today/\u003c/li\u003e\n\u003cli\u003eLeung K. Cy5.5-8-Amino-octanoic acid-Ser-Cys-Pro-Pro-Trp-Gln-Glu-Trp-His-Asn-Phe-Met-Pro-Phe-NH2. In: \u003cem\u003eMolecular Imaging and Contrast Agent Database (MICAD)\u003c/em\u003e. National Center for Biotechnology Information (US); 2004. Accessed April 5, 2025. http://www.ncbi.nlm.nih.gov/books/NBK114193/\u003c/li\u003e\n\u003cli\u003eDowling GP, Keelan S, Toomey S, Daly GR, Hennessy BT, Hill ADK. Review of the status of neoadjuvant therapy in HER2-positive breast cancer. \u003cem\u003eFront Oncol\u003c/em\u003e. 2023;13:1066007. doi:10.3389/fonc.2023.1066007\u003c/li\u003e\n\u003cli\u003eWuerstlein R, Harbeck N. Neoadjuvant Therapy for HER2-positive Breast Cancer. \u003cem\u003eRev Recent Clin Trials\u003c/em\u003e. 2017;12(2):81-92. doi:10.2174/1574887112666170202165049\u003c/li\u003e\n\u003cli\u003eCortazar P, Zhang L, Untch M, et al. Pathological complete response and long-term clinical benefit in breast cancer: the CTNeoBC pooled analysis. \u003cem\u003eLancet Lond Engl\u003c/em\u003e. 2014;384(9938):164-172. doi:10.1016/S0140-6736(13)62422-8\u003c/li\u003e\n\u003cli\u003eNOAH Trial Shows Survival Benefit With Neoadjuvant Trastuzumab \u0026ndash; Hematology \u0026amp; Oncology. Accessed February 14, 2023. https://www.hematologyandoncology.net/archives/february-2010/noah-trial-shows-survival-benefit-with-neoadjuvant-trastuzumab/\u003c/li\u003e\n\u003cli\u003eUntch M, Fasching PA, Konecny GE, et al. Pathologic complete response after neoadjuvant chemotherapy plus trastuzumab predicts favorable survival in human epidermal growth factor receptor 2-overexpressing breast cancer: results from the TECHNO trial of the AGO and GBG study groups. \u003cem\u003eJ Clin Oncol Off J Am Soc Clin Oncol\u003c/em\u003e. 2011;29(25):3351-3357. doi:10.1200/JCO.2010.31.4930\u003c/li\u003e\n\u003cli\u003eUntch M, Rezai M, Loibl S, et al. Neoadjuvant treatment with trastuzumab in HER2-positive breast cancer: results from the GeparQuattro study. \u003cem\u003eJ Clin Oncol Off J Am Soc Clin Oncol\u003c/em\u003e. 2010;28(12):2024-2031. doi:10.1200/JCO.2009.23.8451\u003c/li\u003e\n\u003cli\u003eNami B, Maadi H, Wang Z. Mechanisms Underlying the Action and Synergism of Trastuzumab and Pertuzumab in Targeting HER2-Positive Breast Cancer. \u003cem\u003eCancers\u003c/em\u003e. 2018;10(10):342. doi:10.3390/cancers10100342\u003c/li\u003e\n\u003cli\u003eGianni L, Pienkowski T, Im YH, et al. 5-year analysis of neoadjuvant pertuzumab and trastuzumab in patients with locally advanced, inflammatory, or early-stage HER2-positive breast cancer (NeoSphere): a multicentre, open-label, phase 2 randomised trial. \u003cem\u003eLancet Oncol\u003c/em\u003e. 2016;17(6):791-800. doi:10.1016/S1470-2045(16)00163-7\u003c/li\u003e\n\u003cli\u003eSwain SM, Baselga J, Kim SB, et al. Pertuzumab, trastuzumab, and docetaxel in HER2-positive metastatic breast cancer. \u003cem\u003eN Engl J Med\u003c/em\u003e. 2015;372(8):724-734. doi:10.1056/NEJMoa1413513\u003c/li\u003e\n\u003cli\u003eGiordano SH, Franzoi MAB, Temin S, et al. Systemic Therapy for Advanced Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: ASCO Guideline Update. \u003cem\u003eJ Clin Oncol Off J Am Soc Clin Oncol\u003c/em\u003e. 2022;40(23):2612-2635. doi:10.1200/JCO.22.00519\u003c/li\u003e\n\u003cli\u003eHoang TH, Thi HTP. 15P HER2-positive breast cancer in a low-middle income country (LMIC): Lack of pathology capability and the urgent need for targeted treatment. \u003cem\u003eAnn Oncol\u003c/em\u003e. 2024;35:S1410. doi:10.1016/j.annonc.2024.10.035\u003c/li\u003e\n\u003cli\u003eDavey MG, Browne F, Miller N, Lowery AJ, Kerin MJ. Pathological complete response as a surrogate to improved survival in human epidermal growth factor receptor-2-positive breast cancer: systematic review and meta-analysis. \u003cem\u003eBJS Open\u003c/em\u003e. 2022;6(3):zrac028. doi:10.1093/bjsopen/zrac028\u003c/li\u003e\n\u003cli\u003eSchneeweiss A, Chia S, Hickish T, et al. Long-term efficacy analysis of the randomised, phase II TRYPHAENA cardiac safety study: Evaluating pertuzumab and trastuzumab plus standard neoadjuvant anthracycline-containing and anthracycline-free chemotherapy regimens in patients with HER2-positive early breast cancer. \u003cem\u003eEur J Cancer Oxf Engl 1990\u003c/em\u003e. 2018;89:27-35. doi:10.1016/j.ejca.2017.10.021\u003c/li\u003e\n\u003cli\u003ePhung HT, Nguyen HT, Nguyen TV, Nguyen TV, Dinh LAT, Nguyen CV. Pathological Complete Response with Neoadjuvant Trastuzumab Combined with Chemotherapy in HER2 Positive Breast Cancer: A Single Institution Retrospective Analysis from Vietnam. \u003cem\u003eBreast Cancer Dove Med Press\u003c/em\u003e. 2020;12:117-122. doi:10.2147/BCTT.S268369\u003c/li\u003e\n\u003cli\u003ePh\u0026ugrave;ng Thị Huyền. KẾT QUẢ ĐIỀU TRỊ BỔ TRỢ TRƯỚC PH\u0026Aacute;C ĐỒ H\u0026Oacute;A CHẤT KẾT HỢP TRASTUZUMAB V\u0026Agrave; PERTUZUMAB TR\u0026Ecirc;N UNG THƯ V\u0026Uacute; C\u0026Oacute; HER2-NEU DƯƠNG T\u0026Iacute;NH | Tạp ch\u0026iacute; Y học Việt Nam. January 12, 2022. https://tapchiyhocvietnam.vn/index.php/vmj/article/view/1761\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"HER2-positive breast cancer, neoadjuvant treatment, 4AC-4THP regimen, pCR","lastPublishedDoi":"10.21203/rs.3.rs-6400760/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6400760/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eTo assess the efficacy of the 4AC-4THP neoadjuvant treatment regimen in Vietnamese patients diagnosed with HER2-positive breast cancer.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective analysis of all 50 HER2 positive breast cancer patients received neoadjuvant therapy with 4AC- 4THP in three institutions in northern Vietnam from January 2016 to October 2024. Pathological response was evaluated using Chevallier\u0026rsquo;s criteria, in which complete pathological response was defined as yT0yN0 or yTisN0.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eFifty eligible HER2 positive breast cancer patients treated with 4AC- 4THP regimens in a neoadjuvant setting at Hanoi Medical University Hospital, Vietnam National Cancer Hospital and Hanoi Oncology Hospital were included in the analysis. Median age was 41 (range 26\u0026ndash;67 years). Of these 50 patients, 41 (82%) were premenopausal, while 9 (18%) were postmenopausal; 21 patients (42%) had hormone receptor-positive. The overall clinical complete response (cCR) rate for both tumors and lymph nodes was 56% (23 out of 50). The total pathological complete response (pCR) rate was 78% (39 out of 50). pCR was achieved in 40 out of 50 patients (80%) for breast tumors and in 32 out of 34 patients (94.1%) for lymph nodes. There was no significant association between pCR rate and age, tumor grade, hormone receptor status, and Ki-67 expression.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe 4AC-4THP regimen in neoadjuvant treatment for HER2-positive breast cancer has shown high therapeutic efficacy, achieving a pCR rate of 78.0%.\u003c/p\u003e","manuscriptTitle":"Pathological Complete Response with the 4AC-4THP Regimen in Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis in Vietnam","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-22 13:14:27","doi":"10.21203/rs.3.rs-6400760/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6e1c727c-3e78-4294-9a04-d135a7c5d66e","owner":[],"postedDate":"May 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-30T13:54:09+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-22 13:14:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6400760","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6400760","identity":"rs-6400760","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}