Phoenix—The combination of excision and radiofrequency ablation (eRFA) of the lumpectomy site at the time of surgery may reduce the need for further operations and provide an inexpensive and accessible alternative to radiation therapy for breast cancer, according to research presented at the 2012 meeting of the American Society of Breast Surgeons (ASBrS).
“Margin activity is the only prognostic factor that surgeons can affect,” said Misti Wilson, MD, University of Arkansas for Medical Sciences (UAMS), in Little Rock. “Studies have shown that [the] margin factor is the strongest predictor of local recurrence, which can range from 7% with negative margins to 27% in positive margins. But even with our best efforts, 20% to 40% of patients require re-excision for close or positive margins.”
The biggest obstacle to achieving negative margins is that there is no way for a surgeon to be certain that he or she has attained that goal at the time of surgery, explained V. Suzanne Klimberg, MD, Muriel Balsam Kohn Chair in breast surgical oncology, UAMS, and president of ASBrS.
“The pathologist can’t look at everything. For a 2-cm piece of tissue they would have to get 3,000 sections, which is impossible,” Dr. Klimberg said. ”The fact is it’s more important what I left behind than what I took out. The only way to sterilize that cavity is to use some steam or heat, and that’s basically what we’re doing.”
Radiation after lumpectomy is equal to mastectomy in terms of local recurrence and survival, but the cosmetic effects of radiation can be less than desirable. “Radiation is the gift that keeps on giving—it keeps shrinking the breast over time,” Dr. Klimberg said.
With RFA, “the heat takes care of what the radiation does, at the same time, and doesn’t have long-lasting effects. You end up with a very nice cosmetic result,” she said.
Another limitation to radiation therapy is that it is not practical or even feasible for all patients. “We live in a rural state, Arkansas, and we have patients who choose mastectomy because they can’t afford to leave their livelihood, to leave the farm animals for six weeks or even a week to come in for radiation,” Dr. Klimberg said.
Although some centers do offer intraoperative radiation, its cost can be prohibitive.
“The machines cost more than a million dollars to set up,” Dr. Klimberg said. “[RFA] technology costs less than $30,000 to set up and is very low-maintenance, so it would be conducive to have in small and rural hospitals. It’s the only thing being introduced for treating patients that is less expensive, so it would also be practical in Third-World countries where, for the most part, women get mastectomies.”
People have tried to ablate the tumor within the breast, but tumors have a different density and resistance from normal tissues, “so unless it’s a very tiny tumor, it’s very difficult to use heat, laser or current to ablate a tumor,” Dr. Klimberg said. “To achieve the best results, you have to take the tumor out and ablate the margins, and that’s the difference between what we’re doing and what other people have tried.”
To test their hypothesis that eRFA could extend the margin by 1 cm, decrease the re-excision rate and provide benefits similar to radiation at the time of surgery, the researchers conducted a Phase II trial of that two-step process in 73 patients with invasive breast cancer and an average tumor size of 1.1±0.61 cm (range, 0.2-2.5 cm) who did not undergo adjuvant or neoadjuvant chemotherapy.
“After standard surgical lumpectomy, a purse-string suture was placed around the cavity, and our ablation probe was placed into the cavity and maintained at 100°C for 15 minutes. Doppler sonography was used to follow margin ablation. Our preclinical and in vivo study showed this consistently affected a 1-cm ablation zone,” Dr. Wilson said.
Of the 73 patients, 19 had inadequate margins less than or equal to 2 mm. Of these patients, 16 (84%) with close or focally positive margins did not require re-excision. “Only three out of 73 patients returned to the operating room for re-excision,” Dr. Wilson said.
In the median follow-up of 55 months, there was only one local recurrence and there were three elsewhere recurrences, all in the ipsilateral breast. Of the 40 patients who were scored using Radiation Therapy Oncology Group (or RTOG) cosmesis scoring, 90% reported good to excellent cosmesis.
“In conclusion, eRFA could reduce the need for re-excision to obtain adequate margins. Long-term follow-up suggests that in patients with favorable breast cancer, or those who can’t or won’t have radiation, eRFA could reduce local recurrence without need of radiation therapy,” Dr. Wilson said.
“I think this is very promising technology, and not just for women who cannot afford radiation or who live far from a radiation facility,” said Deanna J. Attai, MD, Center for Breast Care, Inc., in Burbank, Calif. “If this is proven to be as effective as radiation therapy, whole-breast or partial-breast, with fewer side effects and is much more cost-effective, this may quickly become the standard of care for women undergoing breast-conserving therapy.”
The study was relatively small, but had a respectable follow-up, she said. “In addition, the number of patients actually exceeds the number in the initial FDA-approval trial for the MammoSite [Hologic] catheter.”
More data are needed before drawing conclusions, Dr. Attai added, noting that a multicenter registry trial is currently enrolling patients.