Biopsy-based risk stratification of patients prior to percutaneous renal cryoablation (PRC) may be helpful in identifying patients at higher risk of primary treatment failure, according to a new study.

The study, led by Ithaar H. Derweesh, MD, of the University of California San Diego in La Jolla, was a retrospective analysis of 153 patients who renal cell carcinoma (RCC) documented by perioperative biopsy. Patients had a median follow-up of 48 months. Dr. Derweesh’s team divided the cohort into patients who experienced recurrence (18 patients, 11.8%) and those who did not (135 patients, 88.2%). The 2 groups were similar with respect to demographics, R.E.N.A.L score, and number of probes used.

Results showed that the recurrence group had significantly larger tumors than the no-recurrence group (median 3.1 vs 2.4 cm) as well as a significantly greater proportion of high-grade tumors (33% vs 0.7%) and tumors with clear cell histology (77.8% vs 45.9%), the investigators reported online in the World Journal of Urology.

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The 4-year recurrence-free survival (RFS) was 100% for grade 1 tumors compared with 80% for grade 2/3 tumors. The 4-year RFS for patients with clear cell RCC and those other RCC types did not differ significantly (88% vs 97%).

“While these findings require further confirmation, they nonetheless suggest a rethinking of the current algorithm of ablative management,” they investigators wrote.

The association of higher grade and clear cell histology with an increased likelihood of disease recurrence and progression suggests a need for increased emphasis on risk stratification based on preoperative biopsy findings, Dr. Derweesh and his colleagues concluded.

Patients with low-grade clear cell or non-clear cell histology may be more effectively treated by ablation, whereas patients with clear cell histology and higher tumor grade may be counseled as to the increased risk of experiencing ablative treatment failure and potentially steered to other management options, according to the investigators.

Dr. Derweesh’s group said that despite increasing importance attached to biopsy as a determine for management of small renal masses, “most research focusing on predictive factors related to ablative success has focused on technical factors, surgical approach, and type of ablative technology, while predictive ability of biopsy detected histology and grade on treatment success has been little studied.”

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