Nephron-sparing surgery beats ablation for small renal masses

By Joanna Lyford, Senior medwireNews Reporter

Nephron-sparing surgery (NSS) is more effective than ablation for the treatment of clinical stage T1a renal masses, research findings show.

Disease-specific survival was twice as high following NSS as it was following ablation, although the absolute difference was small and may be of minor clinical relevance, say the authors.

Jared Whitson (University of California San Francisco, USA) and co-workers undertook a population-based cohort study using the Surveillance, Epidemiology, and End-Results (SEER) cancer registry to compare the effectiveness of NSS and ablation for T1a renal cell carcinoma.

Between 1998 and 2007 a total of 8818 such patients were included in the SEER database, of whom 7704 were treated with NSS and 1114 with ablation. The median duration of follow up was 2.8 years in the NSS group and 1.6 years in the ablation group.

A total of 716 patients died during follow up, of whom 15% died from RCC: 91 (1.2%) in the NSS group and 19 (1.7%) in the ablation group.

In univariate analysis, ablation was associated with a 2.6-fold greater likelihood of kidney cancer death as compared with NSS. The hazard ratio (HR) fell to 1.9 after adjustment for multiple confounders; variables that influenced RCC mortality were age, gender, marital status, and tumor size.

Of note, the predicted probability of disease-specific survival at 5 years was similar in the two treatment groups, at 98.3% with NSS and 96.6% with ablation, suggesting that the treatment-related difference in outcomes "may only be realized by patients with long life expectancies," note the authors.

Further analyses uncovered differences in outcome among the various types of ablation, such that the risk for death compared with NSS was greatest with ablation of unspecified type (HR=2.5), lowest with cryoablation (HR=1.5), and intermediate with radiofrequency ablation (HR=2.2).

Whitson et al conclude: "Our findings indicate that in a population-based cohort with cT1a renal masses, those who undergo ablation suffer at least a two-fold worse disease-specific survival than those who undergo NSS… Therefore, in patients who are surgical candidates, NSS should remain the standard of care."

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