Partial nephrectomy is the standard of care for patients with localized renal cell carcinoma, but frail patients and those with certain comorbidities may not be able to withstand surgery. Physicians may recommend deferring treatment or they may suggest a minimally invasive technique such as cryoablation, thermo-ablation, radiofrequency ablation, high intensity focused ultrasound, laser interstitial thermotherapy, microwave thermotherapy or radiosurgery. Which works better for patients?
According to a study published in the Journal of Cardiovascular and Interventional Radiology, doing something is definitely better than doing nothing. Both thermal ablation and cryosurgery provided a dramatic improvement in cancer-specific survival compared to deferred therapy. The study could not say which of the ablative techniques provides the best outcome, as no significant difference appeared between them.
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Renal cell carcinoma treated with thermal ablation. (Source: Creative Commons)
The team of German researchers analyzed results from 733 patients with histopathologically confirmed T1a clear cell renal cell carcinoma in the 2000-2013 Surveillance, Epidemiology, and End Results (SEER) Program urinary cancer file. Of those, 315 underwent cryosurgery, 155 had thermal ablation and 263 deferred therapy. The researchers determined the cancer-specific survival rates of each subgroup using Cox proportional hazard models and performed sensitivity analyses to identify potential confounding caused by comorbidities, a particular risk for this group of patients.
They determined that cryosurgery and thermal ablation boosted cancer-specific survival 73% (thermal ablation) to 75% (cryotherapy) compared to deferred treatment, after adjusting for age at diagnosis, tumor grade and size.
“Local ablative techniques provide relevant survival benefit and are preferable alternatives over deferred therapy,” the researchers wrote.
They suggested that “the survival benefit of local tumor ablation might originate from adequate local tumor control by ablation of malignant cells and adjacent rim of healthy tissue, while preserving renal function.” Deferred therapy, by contrast, may lead to impaired kidney function over time.
Sensitivity analysis showed the results to be quite robust, with various assumptions about comorbidities leading to cancer-specific survival benefits of 91% to 32% for cryosurgery versus deferred therapy. Thermal ablation may be assumed to be as beneficial, as an analysis comparing the two ablative techniques found no significant difference in cancer-specific survival.
The authors concluded that “there is increasing evidence for the benefit of local ablative techniques in localized kidney cancer among patients not willing or unable to undergo nephrectomy. Future studies should investigate these techniques in a randomized trial setting.”
