TUMOR ABLATION FOR SMALL RENAL TUMORS

Tumor ablation appears to be a reasonable alternative to partial nephrectomy for treating localized renal masses, although the evidence is limited, according to a new systematic review.

Resection is the first-line treatment for localized renal-cell cancer (RCC), but thermal ablation is increasingly used for the treatment of T1 tumors, especially in patients with significant comorbidities.

Dr. Karim Bensalah of the University of Rennes, France, and colleagues on the European Association of Urology (EAU) Renal Cell Cancer Guideline Panel evaluated the effectiveness of thermal ablation (TA) compared with partial nephrectomy (PN) for T1N0M0 renal masses in their systematic review of 26 studies and 11 relevant systematic reviews.

The majority of studies were retrospective observational studies with poorly matched controls or single-arm case studies with short follow-up, and the results of virtually all the identified systematic reviews were judged to have low or critically low overall confidence of the results.

Overall, in the individual studies, TA as a treatment for T1 renal masses was deemed safe in terms of complications and adverse events, but its long-term oncological effectiveness relative to PN remains unclear, the researchers write in European Urology Oncology.

In order to address the inadequacies of the current evidence base, the panel recommends better-quality prospective studies with protocol-driven inclusion and exclusion criteria, using appropriate controls and validated outcome measures, with adequate follow-up.

The authors conclude "that the current data are inadequate to make any strong and clear conclusions regarding the clinical effectiveness of TA in the treatment of T1N0M0 renal masses compared with PN. Therefore, TA may be considered an alternative to PN for patients with T1 tumors subject to the above caveats, and if offered, patients must be counseled carefully regarding the prevailing uncertainties associated with TA, at least until more reliable evidence emerges."

Dr. R. Houston Thompson of Mayo Clinic, in Rochester, Minnesota, whose recent study supported the use of ablation in select patients, told Reuters Health by email, "There are plenty of retrospective observations demonstrating that renal tumor ablation is safe with reasonable oncologic outcomes for small renal masses. However, there has not been a prospective randomized controlled trial comparing ablation with surgical excision (partial or radical nephrectomy). Additionally, all of the retrospective evaluations of renal tumor ablation suffer from selection bias, in that there was a reason the patient was counseled towards ablation as opposed to partial nephrectomy."

"For patients with small renal masses, clinicians should continue to discuss the pros and cons of surgery (partial and radical nephrectomy), tumor ablation, and active surveillance," said Dr. Thompson, who was not involved in the review.

Dr. Noah S. Schenkman of the University of Virginia, in Charlottesville, recently reviewed the use of thermal ablation for small renal masses. He told Reuters Health by email, "Ablation offers a potential to treat small renal masses with low morbidity. There is a clear need for unbiased, multi-institutional trials to assess this technology. Patients often have made up their minds before they are given alternatives and will not submit to randomization."

"Most important is giving patients the facts about the procedures and entering into shared decision making," said Dr. Schenkman, who also was not connected to the new review. "Not all physicians can offer ablation and partial nephrectomy, so choices may be limited based on available technology."

"Referral patterns play a key role; most patients are referred to urologists for small renal mass, but few urologists perform ablation procedures," he added. "Most ablation is performed by radiologists, who have technical expertise, but do not have as much familiarity with the treatment of renal-cell cancers."

He noted that "technology for ablation has changed significantly over the past decade. (It is) difficult to compare older ablation techniques to modern techniques. In my practice, we have abandoned cryoablation and radiofrequency in favor of microwave over the past 5 years due to superior results that we see. Techniques in all surgical procedures vary by surgeon, and it is always difficult to account for these differences in trials."

Dr. Bensalah did not respond to a request for comments.

SOURCE: https://bit.ly/2JW7tNR European Urology Oncology, online March 31, 2020.