NEW ORLEANSA pilot study of ultrasound-guided percutaneous radio-frequency ablation (RFA) in patients with early-stage breast cancer suggests that the technique might someday be an alternative to surgical resection in carefully selected patients.
The goal of these studies is to attain a high rate of local tumor control with minimal morbidity, Francesco Izzo, MD, reported at a poster session of the 36th Annual Meeting of the American Society of Clinical Oncology (ASCO). Dr. Izzo is in the Department of Clinical Trials, G. Pascale National Cancer Institute (NCI), Naples, Italy.
Radiofrequency ablation permits in situ destruction of solid tumors by localized application of heat. The principles of radiofrequency ablation are similar to those of surgical electrocautery, because it produces coagulation necrosis of tissue. An alternating electrical current is passed across an electrode array, and only tissue around the array is heated to cytotoxic temperatures, Dr. Izzo said.
The study included 26 patients with solitary T1 breast cancer (20 patients) or T2 breast cancer (6 patients) treated with radiofrequency ablation at the NCI, Naples, and the University of Texas M.D. Anderson Cancer Center. The average tumor size was 1.8 cm (range, 0.7 to 3 cm). Patients underwent resection immediately after RFA.
Radiofrequency ablation was performed using a 15-gauge monopolar, insulated-shaft needle electrode with a 10-tine multiple array of hook electrodes deployed into the tumor.
Treatment was planned to ablate the tumor and at least a 5 mm margin of surrounding breast tissue.
Fifteen Minutes to Complete
The treatment typically is done in 2 phases: 10W of power is administered for 2 minutes, with 5W increases every minute, until tissue impedance rises and the power rolls off (complete ablation). Radiofrequency ablation can be performed using local or monitored anesthesia, and typically takes about 15 minutes to complete.
The results showed complete coagulation necrosis in 25 of the 26 patients (96%). One patient had a microscopic focus of viable tissue adjacent to the needle shaft site.
Complications of the treatment were limited to two events in 26 patients (8%). There was one incidence of bleeding from the skin insertion site prior to insertion of the needle electrode and one incidence of burning of the skin overlying the tumor.
Based on this pilot study, the researchers conclude that radiofrequency ablation is a safe procedure with a low complication rate, which produced coagulation necrosis of the entire T1 or T2 breast cancer in 96% of the treated lesions.
Minimally invasive destruction, rather than surgical excision, of early-stage primary breast cancers may be appropriate in carefully selected patients, Dr. Izzo said.
Future studies are planned to assess RFA in the treatment of larger primary breast cancers, he noted.
In an ongoing trial, radiofreqeuncy ablation is being used to treat T1 or T2 cancers, with breast magnetic resonance imaging (MRI) and positron emission tomography (PET) performed 1 week later. This is followed by resection to correlate the findings from MRI, PET, and pathology.
A multi-institutional trial of breast RFA and sentinel node biopsy with selected axillary lymph node dissection is also planned, Dr. Izzo said, to determine local control and patient survival in T1/T2 cancers.