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.

Partial and radical nephrectomy provide comparable long‐term cancer control for T1b renal cell carcinoma

“…Given that those results could be outdated, Badalato et al sought to assess comparative effectiveness between PN and RN in T1b lesions using a more contemporary version of the SEER (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007). 10 In that study, no difference with respect to CSM was recorded between PN and RN. However, the lack of adjustment for baseline comorbidities or OCM might have introduced a bias.…”

“…Finally, it is a retrospective design like all previous studies that assessed oncological outcome in patients treated with PN or RN for T1b. 7,10,30 In conclusion, PN for T1b RCC is safe compared with RN. That being said, no superior OCM advantage was recorded for PN relative to RN in such patients, which could render the indication of PN over RN less appealing and questionable if functional outcomes are considered.…”

“…This limitation was shared with previous studies. 10,30 Accounting for comorbidities could have altered the current findings. However, we adjusted for OCM, which might represent a relative estimate for comorbidities.…”

“…However, previous studies using population-based data showed that utilization of PN remained low in the community setting (5-9%). 9,10 The reluctance of nephron-sparing consideration amongst individuals with T1b RCC might stem from the paucity of data confirming the safety of PN relative to RN in contemporary years. Whereas a recent study using a population-based cohort originating from the USA showed that PN resulted in comparable oncological outcomes after RN, the authors omitted to account for the effect of baseline comorbidities at surgery, which represent an important predictor of OCM.…”

“…Whereas a recent study using a population-based cohort originating from the USA showed that PN resulted in comparable oncological outcomes after RN, the authors omitted to account for the effect of baseline comorbidities at surgery, which represent an important predictor of OCM. 10 To address this limitation, we sought to compare and evaluate CSM after accounting for OCM, and vice versa, between PN and RN using a retrospective population-based cohort of patients diagnosed with T1bN0M0 RCC. We hypothesized that PN is associated with comparable cancer control outcomes relative to RN.…”