The evaluation of therapeutic outcomes of percutaneous US/CT-guided bipolar radiofrequency ablation for small renal masses under local anesthesia.

556 Background: This study is to evaluate the safety and feasibility of local anesthesia (LA) for percutaneous ultrasound/computed tomography (US/CT)-guided bipolar radiofrequency ablation (RFA) for small renal masses (SRMs) by comparing the LA with general anesthesia. Methods: A retrospective review was carried out between 2018 to 2023, 212 patients with SRMs were treated with US/CT-guided bipolar RFA. General anesthesia (GA) was performed in 91 and LA was performed in 121 patients. Demographics, tumor characteristics, peri-procedural data, pathologic and follow-up outcomes were analyzed. The factors associated with pain were also identified. Results: There was no significant difference in demographics and tumor characteristics between the LA and GA group. Several statistically significant decrease were observed in terms of procedural time ( P <0.001), hospital stays ( P <0.001) and hospital costs ( P <0.001). The maximum perceived pain in LA group comprised 57.9% (70 of 121) mild, 42.1% (51 of 121) moderate. The anxiety in LA group comprised 62.0% (75 of 121) mild, 36.3% (44 of 121) moderate, 1.7% (2 of 121) severe. On multivariate analysis, tumor diameter was a significant predictor for pain in RFA procedure (OR 1.470, P <0.001). All patients were followed up for a median (range) of 36 (12-48) months. Local recurrence occurred in 15.7% (19 of 121) of the LA group and in 13.2% (12 of 91) in GA group ( P =1.000). Moreover, there was no significant difference in the difference between postoperative eGFR and preoperative eGFR when comparing the two groups. Conclusions: Percutaneous bipolar RFA of SRMs using CT and ultrasound guidance under LA can be an effective and tolerable method for patients who are unfit for surgery and provide satisfactory oncologic control.