LAUSR

This is a single institutional retrospective analysis of the perioperative outcomes, immediate treatment failure and surgical success of microwave ablation therapy in patients, performed at Humanitas Research Institute, with stage T1a renal cell carcinoma. We performed a retrospective analysis of our database that includes data of patients with RCC who are candidates for MWA treated in our centre between 2018 and 2023. All patients had a preoperative CT/MRI to classify the renal masses according to PADUA, SPARE, and R.E.N.AL. nephrometry scores. All cases were discussed in a multidisciplinary setting to define patients’ eligibility and technical feasibility of the intervention. Patients under 18 years, and those with incomplete pre, intra or post-operative data were excluded. The characteristics of the population are confronted based on the achievement of surgical success, and reported using Chi-square test, as medians and interquartile ranges, and compared by Mann-Whitney U test. In patients in which surgical success was achieved, the lesions were smaller (19 vs 29 mm; p<0.01) and had a lower RENAL score (7 vs 8; p <0.01). These lesions were also ablated in less time (9 vs 14 min; p<0.00). Successfully treated lesions were more polar in location (p=0.02). Microwave ablation of renal masses is safe and feasible, with an acceptable rate of major complications (5.6%) and a good complete ablation achievement rate of 73.9%. An accurate selection of patients is mandatory to avoid incomplete ablation and major complications, as lesion size is one of the driving factors for surgical success.