Overall survival advantage with partial nephrectomy: A bias of observational data?

Abstract

BACKGROUND Partial nephrectomy (PN) and radical nephrectomy (RN) are standard treatments for a small renal mass. Retrospective studies suggest an overall survival (OS) advantage, however a randomized phase 3 trial suggests otherwise. The effects of both surgical modalities on OS were evaluated compared with controls. METHODS A matched cohort study was performed using the Surveillance, Epidemiology, and End Results (SEER)-Medicare dataset. Individuals treated with PN or RN for localized renal cell carcinoma (RCC) measuring ≤4 cm were compared with 2 control groups (non-muscle-invasive bladder cancer (BCC) and noncancer controls (NCC). Using a greedy algorithm, RCC groups were matched with controls by demographics and comorbidities. OS for surgical groups and controls were compared. The cause of death was evaluated for cancer groups when differences in OS were noted. RESULTS Patients undergoing PN and RN were matched with controls. All cancer groups had >95% 10-year cancer-specific survival (CSS). Median OS was similar between RN (9.05 years) and BCC (8.67 years; P =.067) and NCC (8.77 years; P =.49). Median OS was improved for PN (10.45 years) compared with BCC (8.75 years; P