Partial and radical nephrectomy for pT1 renal cell carcinoma: Results of the Saturn project

Introduction & Objectives: To compare oncological results of elective nephronsparing surgery (NSS) and radical nephrectomy (RN) in patients with pT1 renal cell carcinoma (RCC). Materials & Methods: The Surveillance And Treatment Update Renal Neoplasms (SATURN) study collected the data of 5463 patients with RCC treated at 16 Italian institutions from 1995 to 2007. In the present analysis, we evaluated 3320 patients with pT1a/pT1b pN0/Nx M0 who underwent RN or elective NSS. The Kaplan-Meier method was used to calculate survival functions, and differences were assessed with the log-rank statistic. Univariable and multivariable Cox regression models addressed cancer-specific mortality. Results: 2107 patients were male and 1113 female. Mean age at surgery was 61.3 ± 12.2 years. 1832 patients had pT1a RCC, 820 (44.8%) treated by RN and 1012 (55.2%) with NSS; 1388 patients had pT1b RCC, 1178 (84.9%) treated by and 210 (15.1%) with NSS. With regard to the pT1a cases, patients age, gender, mode of presentation, clinical and pathological tumor size, histological type, and Fuhrman nuclear grade were significantly different between patients undergoing RN or NSS (all p values ≤ 0.005). Five-year cancer-specific survival (CSS) estimates were 96.3% and 96.6% in patients treated by RN and NSS, respectively (log rank p 0.33). In Cox univariable analysis, type of surgery was not significantly associated with CSS (H.R. 0.8; p=0.33) and in Cox multivariable analysis, only age and Fuhrman grade were independent predictors of CSS in pT1a RCC. With regard to the pT1b cases, patients age, ECOG performance status, mode of presentation, clinical and pathological tumor size, histological type, and Fuhrman nuclear grade were significantly different between patients undergoing RN or NSS (all p values ≤ 0.01). Five-year cancer-specific survival (CSS) estimates were 95.6% and 94.7% in patients treated by RN and NSS, respectively (log rank p 0.78). In Cox univariable analysis, type of surgery was not significantly associated with CSS (H.R. 0.9; p=0.78) and in Cox multivariable analysis, only age, Fuhrman grade, and tumor multifocality were independent predictors of CSS in pT1b RCC. Conclusions: Our data suggest that RN and NSS have overlapping results in terms of CSS both in pT1a and pT1b RCC. Elective NSS in renal masses larger than 4 cm may be considered as a valuable treatment in selected cases.