Positive Margins in Laparoscopic Partial Nephrectomy in 855 Cases: A Multi-Institutional Survey From the United States and Europe

Purpose: Open partial nephrectomy has emerged as the standard of care in the management of renal tumors smaller than 4 cm. While laparoscopic radical nephrectomy has been shown to be comparable to open radical nephrectomy with respect to long-term outcomes, important questions remain unanswered regarding the oncological efficacy of laparoscopic partial nephrectomy. We examined the practice patterns and pathological outcomes following laparoscopic partial nephrectomy. Materials and Methods: A survey was sent to academic medical centers in the United States and in Europe performing laparoscopic partial nephrectomy. The total number of laparoscopic partial nephrectomies, positive margins, indications for intraoperative frozen biopsy as well as tumor size and position were queried. Results: Surveys suitable for analysis were received from 17 centers with a total of 855 laparoscopic partial nephrectomy cases. Mean tumor size was 2.7 cm (±0.6). There were 21 cases with positive margins on final pathology, giving an overall positive margin rate of 2.4%. Intraoperative frozen sections were performed selectively at 10 centers based on clinical suspicion of positive margins on excised tumor. Random biopsies were routinely performed on the resection bed at 5 centers. Frozen sections were never performed at 2 centers. Of the 21 cases with positive margins 14 underwent immediate radical nephrectomy based on the frozen section and 7 were followed expectantly. Conclusions: Early experience with laparoscopic partial nephrectomy in this multicenter study demonstrates oncological efficacy comparable to that of open partial nephrectomy with respect to the incidence of positive margins. The practice of intraoperative frozen sections varied among centers and is not definitive in guiding the optimal surgical treatment.