Long-term oncologic outcomes of positive surgical margins following robot-assisted partial nephrectomy

Background: Previous reports on positive surgical margin (PSM) after robot-assisted partial nephrectomy (RAPN) have reached inconsistent conclusions as to the impact of a PSM on oncologic outcomes. We sought to determine the effect of PSM on long-term cancer recurrence and survival outcomes. Methods: We queried our renal oncology database for patients having undergone RAPN and compared recurrence-free survival (RFS) and overall survival (OS) between patients with PSM and negative surgical margin (NSM). Kaplan-Meier analysis was also performed for RFS and OS for PSM versus NSM. Results: Of the 432 patients who underwent RAPN we identified 29 (6.7%) patients with PSM and 403 (93.3%) patients with NSM. Median follow-up for the overall cohort was 45.1 months. Three of the 29 patients with PSM and fourteen of the 403 patients with NSM had disease recurrence (P=0.09). RFS at 24, 48, and 72 months was 95.8%, 90%, and 85.5% for patients with NSM and 96.6%, 86.6%, and 80.4% for patients with PSM, respectively (log-rank P value =0.382). OS at 24, 48, and 72 months was 98%, 93.1%, and 89.7% for patients with NSM and 96.3%, 91.2%, and 85.2% for patients with PSM, respectively (log-rank P value =0.584). Conclusions: While PSM are relatively uncommon, their presence still serves as a potential risk factor for worse oncologic outcomes. In instances of PSM, immediate secondary intervention is most likely unnecessary and more attentive long-term clinical follow-up, especially in patients with high-risk features, may be more advisable.