Survival after partial and radical nephrectomy for the treatment of stage T1bN0M0 renal cell carcinoma (RCC) in the USA: a propensity scoring approach

Abstract

Study Type - Therapy (cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Partial nephrectomy has become the standard of care for T1a renal tumours, and the application of nephron-sparing techniques has increasingly been expanded to patients with localized T1b cancers. However, the relative efficacy of partial versus radical nephrectomy for these medium-sized tumours has yet to be definitively established. This study employs a propensity scoring approach within a large US population-based cohort to determine that no survival differences exist among patients with T1b renal tumours undergoing partial versus radical nephrectomy.

Objectives: To compare survival after partial nephrectomy (PN) vs radical nephrectomy (RN) among patients with stage TIb renal cell carcinoma (RCC) using a propensity scoring approach. Propensity score analysis is a statistical methodology that controls for non-random assignment of patients in observational studies.

Patients and methods: Using the Surveillance, Epidemiology, and End Results registry, 11,256 cases of RCCs of 4-7 cm that underwent PN or RN between 1998 and 2007 were identified. Propensity score analysis was used to adjust for potential differences in baseline characteristics between patients in the two treatment groups. Overall survival (OS) and cancer-specific survival (CSS) of patients undergoing PN vs RN was compared in stratified and adjusted analysis, controlling for propensity scores.

Results: In all, 1047 (9.3%) patients underwent PN. For the entire cohort, no difference in survival was found in patients treated with PN as compared with RN, as shown by the adjusted hazard ratio (HR) for OS (1.10; 95% confidence interval [CI]: 0.91-1.36) and renal-CSS (HR 0.91; 95% CI: 0.65-1.27). When the cohort was stratified by tumour size and age, no difference in survival was identified between the groups.

Conclusions: Even when stratified by tumour size and age, a survival difference between PN and RN in a propensity-adjusted cohort of patients with T1b RCC could not be confirmed. If validated in prospective studies, PN may become the preferred treatment for T1b renal tumours in centres experienced with nephron-sparing surgery.