Patients with small kidney cancer tumors may be more likely to die from the cancer if they are treated with ablation rather than nephron-sparing surgery (NSS), according to researchers.
In a retrospective study of 8,818 patients with clinical stage T1a renal cell carcinoma (RCC), investigators found that those treated with ablation had a twofold increased risk of RCC-related death compared with patients treated with NSS, after adjusting for multiple potential confounders. Despite the increased relative risk of a kidney cancer death associated with ablation, the researchers noted that at five years, the absolute difference in risk is small, Jared M. Whitson, MD, and colleagues at the University of California San Francisco reported in BJU International (2012; published online ahead of print).
A total of 716 subjects (8.1%) died during follow-up; of these, 110 (15%) died from RCC: 91 (1.2%) in the NSS group and 19 (1.7%) in the ablation group. The disease-specific survival rate at five years was 98.2% in the NSS group and 94.4% in the ablation group.
For the study, the researchers used data from the Surveillance, Epidemiology and End Results (SEER) cancer registry. The study included patients with RCC tumors smaller than 4 cm and who had no evidence of distant metastases. Of the 8,818 subjects, 7,704 were treated with NSS and 1,114 underwent ablation.
Dr. Whitson’s group noted that their study is the first well-powered investigation to compare the effectiveness of NSS and ablation. The study, however, had limitations, including a relatively short follow-up in the ablation group (median 1.6 years vs. 2.8 years in the NSS group). The authors pointed out, though, that in more than 100 patients in the ablation group who had more than five years of follow-up, the kidney cancer death risk appeared to increase relative to NSS.
Among the 1,114 patients who underwent ablation, 662 (59%) had cryoablation, 239 (21%) had ablation “not otherwise specified,” and 213 (19%) had radiofrequency ablation.