Population-based comparative effectiveness of nephron-sparing surgery vs ablation for small renal masses


The current retrospective SEER outcomes study of ablation vs surgical extirpation by Whitson et al. represents the most well-powered and unbiased analysis of this critical issue in the urological literature to date. Through the analysis of over 8000 patients over a 9-year period across the USA, the authors have detected a small but significant difference in the risk of cancer death in patients treated via ablation vs surgical extirpation in the form of partial nephrectomy. This article is an outstanding attempt to elucidate an outcome difference between two commonly employed therapies for the small renal mass. It is thoroughly conducted and the conclusions are carefully drawn. The authors acknowledge the flaws in their own study and the absence of level I evidence in this field.

Critics of this study may be quick to point out the lack of randomization, the lack of ability to control for the quality of ablations performed over time, and the mixed use of different ablation technologies at different centres throughout the USA. There will probably never be a randomized trial to test this question and the strength of all population-based research is the ability to analyse comparative effectiveness of interventions as they are actually performed in routine clinical practice. In addition the variation in quality control and it impact on outcome can be applied to the nephron-sparing arm of the study as well.

The particular nuance that is well explored is that, despite a higher prevalence of benign tumours and an older, presumably sicker, population of patients, there is a twofold increased risk of cancer-specific death over a relatively short period of follow-up. This fact should cause significant pause for the clinician contemplating ablation of a malignant small renal mass in a patient with >5-year life expectancy. With longer follow-up of this issue and further meticulous analyses in this field it is likely that an increasing disparity in survival rates between patients treated with surgery and those treated with ablation will be detected.