Evidence mounts that RFA works on solid renal masses
Evidence of percutaneous radio-frequency ablation's success in treating solid renal tumors keeps mounting. The procedure is minimally invasive, safe, and effective, according to studies published simultaneously by Brown University and Mayo Clinic researchers.
Brown Medical School investigators prospectively evaluated RFA results in 32 patients undergoing 38 treatment sessions using CT- and ultrasound-guided RFA. RFA was successful in 26 patients in one session, while six had to return for retreatment. One of the six retreatment sessions was unsuccessful.
The researchers found that masses requiring a second round of ablation were significantly larger than masses treated in a single session.
The Rochester, MN, study retrospectively reviewed the treatment of 35 tumors in 20 patients, also using CT and ultrasound for therapy guidance. Twenty-seven were treated percutaneously and eight with open surgery. No patients treated showed either recurrence or major morbidity after follow-up.
Both studies, published in the June issue of the American Journal of Roentgenology, averaged nine months of follow-up.
In a select group of patients, physicians can resort to RFA as a band-aid approach that can treat renal cell cancers safely and on an outpatient basis, said coauthor Dr. Damian Dupuy, an associate professor of diagnostic imaging at Brown.
Nephrectomy is the current standard of care for renal masses that cannot be classified as benign by imaging. Less invasive procedures, such as nephron-sparing surgery, partial nephrectomy, and laparoscopic nephrectomy, have recently been introduced. But they are expensive and require general anesthesia and hospitalization. RFA is cheaper and safer than surgery, and it could replace surgery for early stage I patients, Dupuy said.
RFA may not suit all cases, however. Some tumors could be too close to organs susceptible to collateral harm by ablation. Centrally located tumors are also difficult to treat because of heat loss caused by the kidney's extensive vascularity.
Both studies found that most tumors were exophytic: More than 25% of the tumor margin was adjacent to the fat surrounding the diseased kidney. This finding proved particularly convenient for RFA, since peripheral tumors are not in contact with large vessels.
The literature reports 10-year recurrence rates of 4% for nephron-sparing surgery in patients with small, solitary, low-stage renal cell carcinoma. In order to build a reputation as a kidney-sparing technique, RFA must show success rates comparable with those reported for partial nephrectomy, investigators said.
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