Proceedings from an international consensus meeting on ablation in urogenital diseases.

Ablative treatments are an established therapeutic reality in the oncological field. After the first work on the liver, this type of treatment spread has reached almost all districts. The application of ablative therapies in the management of genitourinary tract disease is constantly growing, leading to a huge scientific production, especially in the recent few years. Tissue characteristics and the need to achieve the greatest possible savings in vital structures adjacent to tumoral lesions are expanding the indications of CA and IRE whereas RFA and MWA confirm their role in this field (Table  1 ). The lack of randomized trials and trials comparing ablative techniques with other treatment options, including other ablative therapies, still makes unclear the potential role of ablative techniques in the management of genitourinary tract diseases. Table 1 Recommendation for urogenital ablative treatments Main results Recommendations RCC  -Ablation is superior to LPN in terms of complications rate and residual renal function 1. Ablation techniques should be preferred to LPN in patients with peripheral RCC 2. Ablation alone should be avoided in lesions > 3 cm 3. Consider ablative re-treatment when LR occurs 4. Ablative technique (RFA, MWA, or CA) should be selected according to operator experience 5. Combined treatment (embolization + ablation) can be an option for lesions > 3 cm located in complex locations  -Ablation is equal to LPN in terms of LR and distant metastasis rate  -Ablation is characterized by a possibility for retreatment after LR  -LR is higher in central lesions > 3 cm  -RFA, MWA, and CA provide comparable complication and survival rates  -Combined treatment (embolization + ablation) increases the results in T1a tumors in challenging locations  -Combined treatment (embolization + ablation) increases treatment coverage and reduces blood loss in lesions > 5 cm Adrenal disease  - Ablation finds application in both benign and malign (primary and metastatic) adrenal disease 1. Ablation of adrenal disease should be considered in non-surgical patients as a second-line treatment 2. Alpha blockade should be considered prior to ablation in all patients, in order to reduce side-effects 3. Ablative technique (RFA, MWA, or CA) should be selected according to operator experience  -Ablation for benign disease effectively controls blood pressure, antihypertensive drug therapy, and hormone secretion  -RFA, MWA, and CA show similar local control rates  -Severe adverse events occur in 16% of patients after ablation  -Intraoperative hypertension is the most frequent adverse event  -Hypertensive crisis rate increases in the presence of normal adrenal tissue and when tumor diameter is smaller than < 4.5 cm  -Ablation achieves good local control (81%) and OS (80%)  -Ablation for aldosterone-producing adrenal adenoma can effectively control blood pressure, reduce the need for antihypertensive drugs, and normalize hormone secretion  -Alpha blockade prior to ablation helps prevent hypertensive crises Prostate cancer  -Ablative therapies find their role in the treatment of patients at intermediate risk in which the goals are the downstaging and the prevention of surgical/radiotherapies side effects 1. Ablation of prostate cancer should be considered in intermediate-risk patients and in recurrency as second-line treatment 2. Ablative technique (HIFU, CA, or IRE) should be selected according to operator experience  -HIFU, CA, and IRE are the most applied techniques  -HIFU, CA, and IRE have similar oncological outcomes  -Ablative therapies find application in recurrent prostate cancer  -Ablation appears relatively safe with an acceptable level of side effects Fibroids  -Ablation therapy improves the QoL and alleviates clinical symptoms 1. Surgery and UAE remain the first-line treatment for fibroids 2. MWA should be preferred to RFA for larger myomas 3. HIFU, CA, and Laser ablation have poor literature support to be applied in a clinical setting  -US-MWA is a simple, time-saving, and efficient emerging treatment option for achieving myoma volume reduction  -HIFU appears to have a higher QoL score and lower incidence of significant complications as compared with surgery  -HIFU appears to have a lower QoL score and higher reintervention rate as compared with UAE  -MWA produces larger ablation areas than RFA  -CA and laser ablation are less used LPN laparoscopic partial nephrectomy, LR local recurrence, RFA radiofrequency ablation, MWA microwave ablation, CA cryoablation, RCC renal cell carcinoma, HIFU high-intensity focused ultrasound, US ultrasound, QoL quality of life, UEA uterine artery embolization Recommendation for urogenital ablative treatments 1. Ablation techniques should be preferred to LPN in patients with peripheral RCC 2. Ablation alone should be avoided in lesions > 3 cm 3. Consider ablative re-treatment when LR occurs 4. Ablative technique (RFA, MWA, or CA) should be selected according to operator experience 5. Combined treatment (embolization + ablation) can be an option for lesions > 3 cm located in complex locations 1. Ablation of adrenal disease should be considered in non-surgical patients as a second-line treatment 2. Alpha blockade should be considered prior to ablation in all patients, in order to reduce side-effects 3. Ablative technique (RFA, MWA, or CA) should be selected according to operator experience 1. Ablation of prostate cancer should be considered in intermediate-risk patients and in recurrency as second-line treatment 2. Ablative technique (HIFU, CA, or IRE) should be selected according to operator experience 1. Surgery and UAE remain the first-line treatment for fibroids 2. MWA should be preferred to RFA for larger myomas 3. HIFU, CA, and Laser ablation have poor literature support to be applied in a clinical setting LPN laparoscopic partial nephrectomy, LR local recurrence, RFA radiofrequency ablation, MWA microwave ablation, CA cryoablation, RCC renal cell carcinoma, HIFU high-intensity focused ultrasound, US ultrasound, QoL quality of life, UEA uterine artery embolization

Uterine fibroids represent the most prevalent benign solid tumors found in the female genital tract. They manifest in approximately 20–25% of women of reproductive age [ 50 ]. Gynecologists and specialists in reproductive endocrinology and infertility commonly encounter these fibroids in patients who present with either singular or a combination of symptoms. These symptoms may include heavy menstrual bleeding, infertility, colicky dysmenorrhea [ 50 , 51 ], and recurrent pregnancy loss. The localization of uterine fibroids appears to play a crucial role in determining the frequency and severity of symptomatology. Traditional treatments involve abdominal myomectomy or hysterectomy, as these approaches have long been considered the standard surgical route for addressing symptomatic submucosal fibroids [ 52 – 59 ]. Historically, hysterectomy was routinely recommended for patients whose reproductive desires had been fulfilled, while abdominal myomectomy was considered the only viable option for young patients desiring pregnancy. However, contemporary advancements have led to increased image-guided procedures and a growing array of pharmaceutical agents, each with value for appropriately selected and advised patients. Today, there is a trend toward minimally invasive treatment for uterine myomas [ 60 ]. The most used is uterine artery embolization (UAE), with adverse events related to possible postembolization syndrome, infection, pain, and potential damage to fertility [ 61 ]. Image-guided thermal ablation techniques, such as MWA, RFA, and image-guided HIFU ablation, have been used recently. The primary purpose of the ablation treatment is to improve the quality of life and alleviate the clinical symptoms. Identifying the optimal approach requires the clinician to comprehensively understand the patient’s history, including her fertility desires. Ultrasound-guided percutaneous MWA has emerged as a widely used method for treating symptomatic myomas and adenomyosis [ 62 , 63 ]. This technique consists of percutaneous placement of a microwave antenna through the abdominal wall or vagina under US guidance into the tumor. The needle tip was located 5 mm from the distal end of the myoma to perform tumoral ablation. US guidance allows direct visualization of the needle and the ablation area during the procedure, increasing procedural safety; the ablative effect can be evaluated with ultrasound contrast at the end of the procedure [ 64 ]. In 2021, Liu et al conducted a meta-analysis of ten studies regarding 671 patients with symptomatic leiomyomas (average myoma diameter ranged between 4.9 cm and 7.2 cm) that underwent percutaneous or cervical MWA [ 65 ]. The results reported that the hemoglobin concentration increased significantly at the time of follow-up, as well as the quality of life (measured by uterine fibroid symptom and quality of life questionnaire scores). Furthermore, the reduction volume rate after the MWA treatment was 85% without major adverse events. The results also showed that the mean operation time was 34.48 min during MWA treatments, lower than HIFU therapy (with a mean operation time of 145.6 min) [ 65 ]. Liu et al conducted a comparative meta-analysis on the HIFU and surgery [ 66 ] for treating symptomatic uterine fibroids, analyzing ten studies with 4450 women (2483 of whom underwent HIFU and 1967 of whom underwent surgery). The results showed that the increase in quality of life was higher in the HIFU group compared with the surgery group. The duration of hospital stay and time to return to work were shorter in the HIFU group. The incidence of significant complications was lower in the HIFU group, with a statistically significant value. Instead, the differences in adverse events, symptom recurrence, re-intervention, and pregnancy outcomes were not statistically significant. In 2020, Liu et al produced another comparative metanalysis of UAE and HIFU for treating symptomatic uterine myomas. A total of seven articles involving 4592 women were included in the metanalysis. The results showed that compared with the HIFU ablation group, the QoL scores at the follow-up time were higher in the UAE group. The women in the UAE group had a significantly lower reintervention rate and a significantly lower pregnancy rate than those undergoing HIFU ablation. No statistically significant adverse events were found [ 67 ]. In 2019, Bradley et al conducted a meta-analysis including 32 articles of 1283 patients treated with laparoscopic, transvaginal, or transcervical RFA fibroid ablation. The mean procedure time was 49 min, the time to discharge was 8.2 h, the time to normal activities was 5.2 days, and a decreased fibroid volume at 12 months was 66%. The results showed that RFA significantly reduces fibroid volume and improves fibroid-related quality of life [ 68 ]. Liu et al [ 65 ] reported a volume decrease of 85% after MWA therapy, Verpalen et al [ 69 ] reported a myoma shrinkage of 37.7% after HIFU treatment, and Bradley et al [ 68 ] reported a mean myoma volume decrease of 71% at > 12-month follow-up after RFA therapy. Furthermore, the ablation areas were more extensive for MWA treatment than for RFA up to 6 cm and 5 cm, respectively [ 70 , 71 ]. From the above data, it can be deduced that compared with other thermal ablation techniques like HIFU and RFA, MWA is relatively simple, time-saving, and efficient in myoma volume reduction. Other ablative techniques for treating symptomatic uterine fibroids include cryomyolysis [ 72 ] and laser ablation [ 73 ]. However, very limited evidence exists in the literature that reports directly on the efficacy of these techniques in treating fibroid-related bleeding symptoms. Today, these techniques are still reserved for highly selected patients. All the observations were based on a limited sample size, requiring more in-depth research, particularly multicentric. Better comparative data are still needed. Further, randomized studies must provide sufficient and reliable data, especially on the re-intervention rate and pregnancy outcome.

Percutaneous image-guided ablation techniques are growing as valid alternatives to surgery in a wide spectrum of diseases, especially in patients with a high preoperative surgical risk. In the setting of the genitourinary tract, radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation (CA), irreversible electroporation (IRE), and high-intensity focused ultrasound (HIFU) is the most used by interventional radiologists and other specialties [ 1 ]. Each one of these techniques has both pros and cons due to the type of energy delivered and the action mechanism. RFA exposes tumor cells to a temperature of 60 °C or higher, with the intent to obtain cellular death. The heat-sink effect is the principal limitation of RFA in lesions proximal to large vessels [ 2 ]. The energy transferred by the MWA antenna to the water molecules leads to rapid molecular agitation, frictional heating, and an increase in tissue temperature. Achieving a temperature between 55 °C and 100 °C initiates protein and enzymatic breakdown, and DNA unwinding, resulting in cellular demise and coagulation necrosis. MWA offers various advantages, such as larger ablation volumes, minimal heat sink effect, efficient coagulation of blood vessels, and a swift ablation duration [ 3 ]. CA alternates cooling phases, during which an ice ball is produced within the target tissue, and thawing phase. The alternation produces disruption of cell membranes, resulting in cellular cytotoxicity. In addition, CA is less painful and can be performed under conscious sedation [ 4 ]. IRE works with high-frequent electric pulses generated between two or more electrodes that produce definitive permeabilization of cellular membranes, causing cell death due to the inability to maintain homeostasis. HIFU uses high-power, highly-focused ultrasound beams to generate heat into a specific tissue. Confined coagulative necrosis is obtained in 1 s treatment due to the high temperature (> 75 °C), with saving of the surrounding tissues [ 5 ]. This narrative review article describes the application of ablative techniques in the field of genitourinary tract diseases, exploring the most relevant results of the recent literature and summarizing major recommendations from a consensus international meeting (MIOLive 2023—Rome—ITALY).