Microwave treatment of renal cell carcinoma adjacent to renal sinus

• This study shows US-guided microwave ablation appears to be a promising method to treat renal cell carcinoma adjacent to renal sinus.
• The estimated 1-, 3- and 5-year RCC-related survival were 100%, 93.3% and 93.3%, respectively.
• The estimated 1-, 3- and 5-year overall survival were 97.1%, 87.8%, 83.6%, respectively.
• For patients with RCC ≤4 cm, initial ablation success was 100% (29/29) and the estimated 5-year disease-free survival were 81.5%.

PurposeTo evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus.Materials and methodsThis retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1 day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits.ResultsIAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4 cm (100%, 29/29) and RCCs >4 cm (75%, 9/12, p = 0.021). During the median follow-up of 37.6 (range, 3.0–97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4 cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation.ConclusionUS-guided percutaneous MWA appears to be a promising method for RCCs adjacent to renal sinus, especially for tumors ≤4 cm.