Oncologic outcomes of patients with positive surgical margin after partial nephrectomy: a 25-year single institution experience

Abstract

To evaluate oncologic outcomes and management of patients with microscopic positive surgical margin (PSM) after partial nephrectomy (PN) for renal cell carcinoma (RCC). We reviewed our database to identify patients who underwent PN between 1990 and 2015 for RCC and had PSM on final pathology. A 1:3 matching was performed to a negative surgical margin (NSM) cohort. Kaplan-Meier method and log-rank test were used to estimate survival and differences in outcomes, respectively. Cox proportional hazards models were conducted to estimate the Hazards ratio. A total of 2297 patients underwent PN at our institution, of which 1863 (81%) had RCC. Microscopic PSM was found in 34 (1.8%) RCC patients who were matched to 100 patients with NSM. Of these 34 patients, local recurrence (n=4), distant kidney recurrences (n=4), and metastases (n=5) developed during a median follow-up of 62months. Bilateral tumors/tumors in a solitary kidney (n=12/13, 92%), and multifocal tumors (n=7/13, 54%) were found in patients who developed recurrence/metastasis. PSM patients were at a higher risk of shorter overall survival (p=0.001), local recurrence-free survival (p=0.003), distant recurrence-free survival (p=0.032) and metastasis-free survival (p=0.018). There was statistically significant association between PSM and bilateral tumors, prior treated RCC at presentation and higher nephrometry score in multivariable model. There was a low rate of microscopic PSM in our large cohort of patients undergoing PN despite tumor complexity. Higher nephrometry score, bilateral tumors, and prior treated RCC independently predicted PSM which showed worse survival, recurrence and metastasis compared to patients with NSM.