Researchers identify less risky treatment for small renal tumors

By Robin Russell

For renal tumors less than 3 centimeters in diameter, radio frequency ablation is less risky and just as effective as surgery, UT Southwestern Medical Center urologists have found.

Jeffrey Cadeddu, MD

Ablation, which is the removal of tissue through erosive processes, provides excellent outcomes for smaller tumors, but those that are larger than 3 centimeters are more likely to recur, said Dr. Jeffrey Cadeddu, Professor of Urology and Radiology and senior author of a paper that appears in the April edition of the Journal of Urology.     

Researchers previously have known that tumor size influences the effectiveness of ablation procedures, but their ability to identify size cutoffs has been limited by small patient numbers and limited follow-up. This study gives a guideline as to when ablation technologies may be used effectively and when surgery likely will be required.

The most common ablation procedures for renal tumors are radio frequency ablation, in which radio frequency waves pass through a probe to heat and destroy the tumor, and cryoablation, the use of extreme cold to freeze and destroy diseased tissue.

For smaller tumors, ablation procedures can preserve renal function while effectively controlling cancer.

In the study, UT Southwestern urologists examined 159 tumors that had been treated with radio frequency ablation. They evaluated patients with contrast-enhancing imaging before surgery, at six weeks, six months, and annually for at least three years. The five-year disease-free survival rate was 95 percent for tumors smaller than 3 centimeters, and 79 percent for tumors 3 centimeters or larger.

UT Southwestern investigators who participated in the study were Sara Best; Samuel Park; Dr. Ramy Yaacoub, postdoctoral trainee; Dr. Ephrem Olweny, Assistant Instructor in Urology; Yung Tan; and Dr. Clayton Trimmer, Associate Professor of Radiology.

Dr. Cadeddu holds the Ralph C. Smith, M.D., Distinguished Chair in Minimally Invasive Urologic Surgery.