Percutaneous Microwave Ablation versus Laparoscopic Partial Nephrectomy for cT1a Renal Cell Carcinoma: A Propensity-matched Cohort Study of 1955 Patients.

Background Percutaneous microwave ablation (MWA) and laparoscopic partial nephrectomy (LPN) are two modalities indicated for early-stage renal cell carcinoma (RCC) with low extent of invasion. Purpose To compare the long-term results of percutaneous MWA and LPN in the treatment of cT1a RCC. Materials and Methods This retrospective study included 1955 patients with cT1a RCC treated with percutaneous MWA or LPN between April 2006 and November 2017. Propensity score matching was used. Oncologic outcomes were analyzed by using the Fine-and-Gray competing risk models. Results A total of 185 patients underwent percutaneous MWA (mean age, 63.2 years ± 15.2 [standard deviation]) and 1770 underwent LPN (mean age, 50.9 years ± 13.2). During the follow-up (median, 40.6 months), after propensity score matching, no difference was observed between local tumor progression (3.2% vs 0.5%, P = .10), cancer-specific survival (2.2% vs 3.8%, P = .24), and distant metastases (4.3% vs 4.3%, P = .76). Patients who underwent percutaneous MWA had worse overall survival (hazard ratio, 2.4; 95% confidence interval: 1.0, 5.7; P = .049 vs LPN) and disease-free survival (82.9% vs 91.4%, P = .003). Percutaneous MWA led to smaller drop in estimated glomerular filtration rate at discharge (6.2% vs 16.4%, P < .001), smaller estimated blood loss (4.5 mL ± 1.3 vs 54.2 mL ± 69.2), lower cost ($3150 ± 2970 vs $6045 ± 1860 U.S. dollars), shorter operative time (0.5 minute ± 0.1 vs 1.8 minutes ± 0.6), and shorter postoperative hospitalization time (5.1 days ± 2.6 vs 6.9 days ± 2.8) (all P < .001 vs LPN). There were fewer cases of fever in the percutaneous MWA group (16.2% vs 73.0%, P < .001). Conclusion There were no significant differences regarding oncologic outcomes and complications between percutaneous microwave ablation and laparoscopic partial nephrectomy for patients with cT1a renal cell carcinoma. Percutaneous microwave ablation led to smaller renal function change and lower blood loss. For patients who cannot be subjected to the risks of more invasive laparoscopic partial nephrectomy, percutaneous microwave ablation could be an alternative less invasive treatment option. © RSNA, 2020 Online supplemental material is available for this article.

Ultrasound-guided percutaneous microwave ablation of central intraductal papilloma: a prospective pilot study.

Background: Central intraductal papilloma (IDP) has a low risk of cancer evolution; therefore, surgical treatment of IDP is controversial. We sought to validate ultrasound (US)-guided percutaneous microwave ablation (MWA) for minimally invasive treatment of IDP. Methods: Thirteen women with central IDP, including six with nipple discharge, underwent US-guided core needle biopsy and MWA from December 2016 to November 2017. Lesions histologically diagnosed as benign IDP were included. The hydro-dissection technique was used to protect the nipple during the entire ablation procedure. We evaluated and recorded data of complete ablation, volume reduction, and complications. Results: MWA was successfully performed in all patients, with 100% complete ablation, assessed by magnetic resonance imaging or contrast-enhanced US. Mean tumor size was 13.5 ± 4.1 (7.0-20.0) mm; the mean ablation time was 1.4 (0.7-10.3) min. At the median 13.7-month follow-up, mean lesion sizes at 3, 6, and 12 months after MWA were all significantly smaller than that at baseline. Total volume reduction rates were 52.3 ± 18.2% (range, 24.2-81.8%), 72.6 ± 23.1% (range, 39.4-95.9%), and 92.9 ± 7.5% (range, 75.0-100%) at 3-, 6-, and 12-month follow-up, respectively, with significant differences (p < .01). Three lesions with diameters 7 mm, 9 mm, and 12 mm disappeared completely at 3, 6, and 6 months after MWA, respectively, on US imaging. Nipple discharge disappeared immediately after MWA. Cosmetic effects were reported as excellent by all patients and no complications were observed. Conclusion: US-guided MWA of central IDP proved feasible and effective, with considerable volume reduction and satisfactory cosmetic outcomes.

Ultrasound guided percutaneous microwave ablation of benign breast lesions.

The benign breast lesions (BBLs) share a high incidence for women and therapy methods with minimal invasion and better cosmetic outcome are thirsted for. In this study, 122 patients with 198 biopsy-proved BBLs were enrolled. Ultrasound (US)-guided microwave ablation (MWA) was performed with local anesthesia from November, 2013 to April, 2016. The mean longest tumor size assessed was 1.6±0.7 cm (ranging 0.7-4.9 cm). MWA was successfully performed in all cases including 85 lesions adjacent to the skin, pectoralis and areola. The mean ablation time was 3.2mins (ranging 0.5-18.3 mins). 99.5% of BBLs showed complete ablation when assessed by magnetic resonance imaging and 100% of them by US. At the median 14-month follow-up, the BBLs were not palpable in 45.9 % of the cases (palpable in 90.2 % of the cases before MWA) and the mean volume reduction ratio was 78.4±33.5% for total lesions and 89.3±20.8%, 84.7±27.6% and 55.9±32.9% for ≤1.0 cm, 1.1-2.0cm and >2.0 cm lesions in 12-month follow-up, respectively. Cosmesis were reported as good or excellent in 100 % by physician and patients. No side effect was found. The MWA of the BBLs proved feasible and effective, while showing meaningful reduction in volume, palpability and cosmetic satisfying outcomes.

[Long-term effects of ultrasound-guided microwave ablation in the treatment of small renal cell carcinoma].

OBJECTIVE: To evaluate the long-term efficacy of microwave ablation in the treatment of small renal cell carcinoma (RCC). METHODS: We retrospectively analyzed 140 cases of small cell renal carcinoma (151 lesions with a mean diameter of 2.8±0.8 cm) treated between April, 2006 and October, 2015 with ultrasound-guided microwave ablation with cooled-shaft needle antenna. One microwave ablation antenna was used for tumors less than 2 cm in diameter and 2 antennas were used for larger tumors. The patients received enhanced ultrasound and CT/MRI examinations at 1, 3, and 6 months after the operation and every 6 months thereafter. The overall survival, disease-free survival, and local tumor progression rate of the patients were evaluated. RESULTS: The response rate of treatment (complete ablation at one month on enhanced images) was 100% in these patients. The local tumor progression rates at 1, 3, and 5 years were 0.9%, 2.0%, and 7.1%, respectively, and the 1-, 3-, and 5-year distant metastasis rates were 1.6%, 2.5%, and 7.9%, respectively. The overall survival rates of the patients at 1, 3, and 5 years were 98.4%, 94.8%, 89.5%, respectively, with disease-free survival rates of 98.4%, 93.0%, and 83.1%, respectively. No major complications occurred in these cases, and multivariate analysis showed that the tumor number (P=0.015) and tumor growth patterns (P=0.049) were independent risk factors that adversely affected the long-term outcome after surgery. CONCLUSION: Our data show that microwave ablation is a safe and effective modality for treatment of renal cell carcinoma.

Midterm results of percutaneous microwave ablation under ultrasound guidance versus retroperitoneal laparoscopic radial nephrectomy for small renal cell carcinoma.

Laparoscopic radial nephrectomy (LRN) and microwave ablation (MWA) are optional treatment for renal cell carcinoma (RCC). However, the comparative study with two techniques remains lacking. The aim of this study was to evaluate midterm results of MWA vs. LRN in patients with small RCC. A total of 426 patients with ≤ 4 cm RCC were included from April 2006 to October 2012. Ninety-eight patients underwent MWA and 328 patients LRN. The survival, recurrence, and renal function changes were compared between two treatments. Although overall survival after MWA (82.6% at 5 years) was lower than those after LRN (98.6% at 5 years, p = 0.0004), the RCC-related survival (97% at 5 years) was comparable to those following LRN (98% at 5 years, p = 0.38). One local tumor progress occurred at 32 months after MWA and none after LRN. The major complication rates were comparable between two techniques (1.7% in MWA vs. 1.5% in LRN, p = 0.75), but MWA showed less renal function damage than LRN (p < 0.0001). The multivariate analysis showed the presence of postablation extrarenal metastasis may become a predictor of the oncologic outcome (p = 0.059) and treatment modality had no influence (p = 0.965). This study demonstrates that MWA and LRN provide comparable results in small RCC outcomes.

Local tumour progression after ultrasound-guided microwave ablation of liver malignancies: risk factors analysis of 2529 tumours.

OBJECTIVES: To identify the incidence and risk factors that predict local tumour progression (LTP) after ultrasound-guided percutaneous microwave ablation (MWA) of liver malignancies. MATERIALS AND METHODS: One thousand two hundred and nine patients with 2,529 malignant nodules (mean size 2.8 ± 1.4 cm, range 0.9-8.0 cm) were treated by MWA between July 2005 and December 2012. The influence of 11 factors on the risk of LTP was assessed. Univariate Kaplan-Meier and Cox proportional hazard models were used for statistical analysis. RESULTS: The overall LTP was 4.2 % per tumour and 8.6 % per patient with a median follow-up of 20.3 months. LTP per tumour was 4.3 % for primary liver cancer and 4.1 % for metastases (p = 0.32). The survival of LTP and free-LTP patients at 1, 3, and 5 years was 92.4 %, 71.6 %, and 45.1 %, respectively, and 92.9 %, 70.1 %, and 52.4 %, respectively (p = 0.93). By univariate analysis, tumour location, size and ablation time were significant risk factors of LTP. Multivariate analysis identified tumour size (>3.0 cm) to be the only independent predictor of LTP. CONCLUSIONS: MWA of liver malignancies achieves a relatively low-incidence LTP, although LTP risk significantly increases if tumour size >3.0 cm. The technique seems to be appropriate even for patients with a tumour at a risk location. KEY POINTS: • Microwave ablation of liver malignancies achieves a low incidence local tumour progression. • LTP risk significantly increases if the tumour size is >3.0 cm. • MWA seems to be appropriate even for patients with a tumour at a risk location.

US-guided percutaneous microwave ablation versus open radical nephrectomy for small renal cell carcinoma: intermediate-term results.

PURPOSE: To review intermediate-term clinical outcomes of microwave ablation (MWA) compared with open radial nephrectomy (ORN) in small renal cell carcinoma (RCC) patients and to identify prognostic factors associated with two techniques. MATERIALS AND METHODS: This retrospective study was institutional review board-approved. A total of 163 patients (127 men and 36 women) with small RCC (≤4 cm) were included from April 2006 to March 2012. Sixty-five patients underwent MWA and 98 patients underwent ORN. Survival, recurrence, and renal function changes were compared between the two groups. Effect of changes in key parameters (ie, overall survival, RCC-related survival, and metastasis-free survival) was statistically analyzed with the log-rank test. RESULTS: Although overall survival after MWA was lower than that after ORN (P = .002), RCC-related survival was comparable to ORN (P = .78). Estimated 5-year overall survival rates were 67.3% after MWA and 97.8% after ORN; for RCC-related survival, estimated 5-year rates were 97.1% after MWA and 97.8% after ORN. There was one local tumor recurrence 32 months after MWA and none after ORN. Major complication rates were comparable (P = .81) between the two techniques (MWA, 2.5% vs ORN, 3.1%). The MWA group had less surgical time (P < .001), estimated blood loss (P < .001), and postoperative hospitalization (P < .001). Multivariate analysis showed age (P = .014), tumor type (P = .003), postoperative urea nitrogen (P = .042), comorbid disease (P = .005), and treatment modality (P < .001) may become survival rate predictors. CONCLUSION: In intermediate term, ultrasonographically guided percutaneous MWA and ORN provide comparable results in oncologic outcomes. MWA appears to be a safe and effective technique for management of small RCC in patients with little loss of renal function.

US-guided percutaneous microwave ablation of renal cell carcinoma: intermediate-term results.

PURPOSE: To retrospectively review intermediate-term (median, 20.1 months) clinical outcomes after microwave ablation (MWA) of renal cell carcinoma (RCC). MATERIALS AND METHODS: This retrospective study was approved by the institutional review board. The results from 46 patients with 49 RCC nodules (diameter, 0.6-7.7 cm; mean, 3.0 cm ± 1.5 [standard deviation]) treated with ultrasonography (US)-guided percutaneous MWA with cooled-shaft needle antenna from April 2006 to December 2010 were reviewed. One antenna was used for tumors smaller than 2 cm; two, for tumors 2 cm or larger. The patients were followed up with contrast material-enhanced US and computed tomography or magnetic resonance imaging at 1, 3, and 6 months and every 6 months thereafter. The effect of changes in key parameters (including overall survival, disease-free survival, and local tumor progression rate) was statistically analyzed by using the log-rank test. RESULTS: Technical effectiveness (complete ablation at follow-up enhanced imaging 1 month after MWA) was achieved in 48 of 49 (98.0%) tumors, and the metastasis-free rate was 100% (46 of 46). The 1-, 2-, and 3-year local tumor progression rates were 4.6%, 7.7%, and 7.7%, respectively. The cancer-specific survival rate was 100% (46 of 46), and 1-, 2-, and 3-year overall survival rates were 100%, 100%, and 97.8%, respectively. The 1-, 2-, and 3-year disease-free survival rates were 95.4%, 92.3%, and 92.3%, respectively. No major complications occurred. Multivariate analysis showed that tumor number (P = .046), tumor growth patterns (P = .003), and ablation time (P = .04) were independent unfavorable prognostic factors. CONCLUSION: In the intermediate term, US-guided percutaneous MWA appears to be a safe and effective technique for the management of RCC, especially small RCC, in selected patients.