Comparative effectiveness, costs and trends in treatment of small renal masses from 2005 to 2007

What's known on the subject? and what does the study add?: Retrospective data have suggested an increased survival benefit for patients undergoing partial nephrectomy compared to radical nephrectomy, possibly as a result of the avoidance of long-term renalin sufficiency and subsequent sequelae. However, recent level-one evidence has questioned this benefit. Both retrospective studies and randomized controlled trials are not without limitations. There are few population-based data available with respect to the outcomes of partial nephrectomy vs radical nephrectomy. Additionally, there are no population-based studies analyzing the surgical approach (minimally-invasive vs open), as well as other modalities, such as ablation and surveillance. Finally, there is very little information available on the potential differences in cost for each approach. The present study comprises the first comprehensive population-based analysis of the trends, outcomes and costs of all treatment modalities for T1a renal masses from 2005 to 2007.

Objective: To perform a comprehensive analysis of the outcomes and costs for treatments for small renal masses (SRM) using a population-based approach. Partial nephrectomy may be associated with improved survival, although level-one evidence has questioned this survival advantage.

Patients and methods: Using Surveillance, Epidemiology and End Results-Medicare data, we identified 1682 subjects who were diagnosed with SRM from 2005 to 2007. Treatment included open radical nephrectomy (ORN; n = 404), minimally-invasive radical nephrectomy (MIRN; n = 535), open partial nephrectomy (OPN; n = 330), minimally-invasive partial nephrectomy (MIPN; n = 160), ablation (n = 211) and surveillance (n = 42). Postoperative complications, renal insufficiency diagnosis, overall mortality, cancer-specific mortality and postoperative costs were compared. Covariates were balanced before outcomes analysis using propensity score methods.

Results: Although the use of nephron-sparing surgery (NSS) increased over the study period, radical nephrectomy remained the predominant approach for SRM in 2007. Minimally-invasive approaches had shorter lengths of stay (P < 0.001), whereas open approaches had more overall complications, respiratory complications and intensive care unit admissions (all P < 0.003). MIRN and ORN were associated with more peri-operative medical complications, acute renal failure, haemodialysis use and long-term chronic renal insufficiency diagnosis vs NSS (all P < 0.001). Ablation, MIRN and ORN were associated with the highest overall mortality rates (P < 0.001), whereas MIRN and ORN were associated with the highest cancer-specific mortality rates (P < 0.001). Treatment costs were lowest for surveillance ($2911) followed by ablation ($10730), MIRN ($15373), MIPN ($15695), OPN ($16986) and ORN ($17803).

Conclusions: Although not the predominant treatment approach for SRM over the study period, the use of NSS increased and was associated with improved survival, fewer complications and less renal insufficiency. Minimally-invasive approaches confer lower costs.