Impact of positive surgical margins in patients undergoing partial nephrectomy for renal cortical tumours

OBJECTIVE To evaluate the clinical outcome of patients undergoing partial nephrectomy (PN) for renal cortical tumours who had a positive surgical margin (SM), as recent studies have shown that a minimal SM is required to achieve equivalent disease-free survival (DFS). PATIENTS AND METHODS Between 1989 and 2005, 777 PNs were performed at the authors' institution. Clinical and pathology data were obtained from our prospective surgical database after obtaining institutional review board approval. Variables were analysed in a logistic regression model to determine predictors of positive SMs. The clinical outcome was reported for local recurrence and distant metastasis and analysed using the log-rank test. RESULTS Of the 777 PNs, the SM status was documented in 770; the SMs were positive in 57 of 770 (7%). Positive SMs occurred in 33 of 423 (8%) patients with tumours of high malignant potential, and in 24 of 347 (7%) patients with tumours of low malignant potential. On multivariate analysis, an imperative indication for a PN was a significant predictor for a positive SM (P = 0.003). With a median follow-up for survivors of 22 months, there was a local recurrence in two of 57 (4%) patients with a positive SM and four of 713 (0.5%) with a negative SM. No patients with a tumour of low malignant potential had a recurrence, despite having a positive SM. CONCLUSIONS Although local recurrence after PN for renal cortical tumours is rare, our data suggest that patients with a tumour of high malignant potential and a positive SM might have a higher incidence of local recurrence.