Radiofrequency Ablation May Improve Lumpectomy Outcomes

Rabiya S. Tuma, PhD

October 21, 2005

Oct. 21, 2005 (San Francisco) — Cauterizing the surgical margins with radiofrequency ablation (RFA) of the tumor bed after lumpectomy reduces the number of patients who require a second resection, according to data from a pilot study.

"The expected recurrence rate is 16% in these patients, but I had one patient" out of 25 (4%), V. Suzanne Klimberg, MD, told Medscape after her presentation at the American College of Surgeons annual meeting. Dr. Klimberg is a professor of surgery and pathology and director of the Breast Cancer Program at the Arkansas Cancer Research Center in Little Rock.

The U.S. Food and Drug Administration has approved the use of RFA only for the treatment of liver tumors. "No one has used RFA in the cavity" after tumor resection, said Dr. Klimberg.

Her team initially analyzed the effects of RFA in an ex vivo situation, testing the probe on tissue removed during mastectomies. They found that by heating a narrow bowl of tissue to 100°C for 15 minutes with the RFA probe, they could generate a 1-cm margin of clear tissue surrounding the tumor bed. Because 40% of margins are positive or close to tumor tissue, and 25% of recurrences occur in patients with negative margins, killing any tumor cells left behind after resection could dramatically improve patient outcomes.

To test the theory in practice, Dr. Klimberg and colleagues have treated close to 60 patients with the RFA approach. She reported the results of the first 25 patients. Of those, six had ductal carcinoma in situ, four had lobular carcinoma, and 15 had invasive carcinoma.

All patients underwent RFA in the tumor cavity after lumpectomy, as was performed on the ex vivo tissue. Pathology reports confirmed that all 25 women had negative intraoperative margins, as required for inclusion in the trial. However, seven women (28%) had inadequate margins of less than 2 mm. One of those had grossly positive margins and opted for a mastectomy.

The remaining six patients with inadequate margins are at high risk of recurrence, and statistics would predict that approximately five of the women with negative margins would also suffer a recurrence.

Nine patients did receive radiation therapy and most of the others were offered radiation, but declined. If RFA works as the researchers hope, it may obviate the need for adjuvant radiation therapy.

At a median follow-up of 20.0 months (range, 12-38 months), there were no local recurrences and one recurrence in a distinct location in the breast at one year.

The group did not report any adverse events related to RFA, although they noted two burns due to radiation, one of which led to an infection. Six months after surgery and RFA treatment, the tissue treated with RFA cannot be distinguished in a mammogram.

"We may not be able to impact survival, but we will certainly impact our options for breast-conserving surgery," Dr. Klimberg said.

RITA Medical Systems, which manufactures RFA devices, provided support for the study.

ACS 91st Annual Clinical Congress: Papers Session I. Presented Oct. 18, 2005.

Reviewed by Gary D. Vogin, MD

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