Radiofrequency ablation (RFA) can effectively treat small benign tumors in a single session, and long-term outcomes of RFA for renal tumors depend on tumor size, according to the findings of two studies.
Researchers at the University of Texas Southwestern Medical Center in Dallas led by Jeffrey A. Cadeddu, MD, conducted both studies, which were retrospective in design. One study looked at 47 benign small (less than 3.5 cm) renal masses (SRMs) discovered incidentally in 41 patients. The tumors were determined to be benign by concurrent biopsy. The other study focused on 159 renal tumors, most renal cell carcinoma (RCC), in 142 patients, who received as RFA as primary treatment.
In the study of benign small SRMs, all tumors required only a single treatment session. After a mean follow-up of 45 months, no patient experienced a recurrence, defined as tumor growth and enhancement on follow-up axial imaging, the investigators reported online ahead of print in Urology. The median pre- and postoperative glomerular filtration rate was 77 and 68 mL/min/1.73 m2, respectively. The authors noted that the study was limited by its retrospective design and small study sample.
“Long-term follow-up imaging might not be required if successful ablation is determined at the initial post-treatment cross-sectional imaging study,” Dr. Cadeddu’s group concluded. Thus, they noted, patient radiation exposure and cost can be reduced.
Intermediate- and long-term published data support the efficacy of RFA in the treatment of renal cell carcinoma (RCC), the researchers noted, but little or no data exist that clearly demonstrate the efficacy of RFA in ablating incidental benign tumors. “Moreover, unlike the frequent follow-up imaging required of the treated malignant tumor, the appropriate follow-up imaging protocol of these biopsy-confirmed benign tumors is unknown,” they wrote.
Smaller is better
In the other study, published online ahead of print in the Journal of Urology, Dr. Cadeddu and his collaborators demonstrated that long-term outcomes of RFA for renal tumors is better when the treated lesions are relatively small. Pretreatment biopsies were performed for 150 of the 159 tumors. RCC was confirmed in 72% of these tumors. The median tumor size was 2.4 cm and the median follow-up was 54 months (range 1.5 to 120 months). The three- and five-year disease-free survival rates were significantly better in patients with tumors smaller than 3 cm than in those with tumors 3 cm or larger (92% and 95%, respectively, vs. 79% and 79%, respectively).
The authors concluded that their findings confirm that RFA is associated with successful and durable treatment for small renal masses, especially those smaller than 3 cm. Most treatment failures are local and often can be treated successfully with a second ablative session, they observed.