Breast-conserving therapy may be viable option for multiple ipsilateral breast cancer

In In The News by Barbara Jacoby

From: healio.com

Lumpectomy followed by radiation therapy resulted in low rates of local recurrence at 5 years among women with multiple ipsilateral breast cancer, according to phase 2 study results.

The findings — presented at San Antonio Breast Cancer Symposium — also indicated women with two or more malignant lesions in the same breast considering breast-conserving therapy may benefit from breast MRI.

Background and methods

With advances in breast imaging techniques — such as with use of MRI — there has been an increase in detection of additional foci of breast cancer in the same breast of women with newly diagnosed disease, Judy C. Boughey, MD, FACS, professor of surgery and chair of breast and melanoma surgical oncology and the breast cancer disease group at Mayo Clinic in Rochester, Minnesota, told Healio.

“This often results in patients undergoing mastectomy who otherwise may have preferred breast conservation,” Boughey said. “Many patients who present with two or three foci of disease in a breast are recommended mastectomy, as historical studies have shown high local recurrence rates with breast conservation [among] these patients. The main purpose of the current trial was to evaluate whether breast conservation with lumpectomy followed by radiation therapy is appropriate management for patients who have more than one tumor in a single breast.”

The Z11102 prospective, single-arm trial assessed outcomes of lumpectomy and subsequent whole-breast radiation therapy with tumor bed boosts among 204 women (median age, 61.1 years; 83.5% ER-positive/HER2-negative disease) with multiple ipsilateral breast cancer and at least one foci of invasive disease.

All women underwent mammogram and/or breast ultrasound; most underwent breast MRI.

Five-year local recurrence rates after completion of radiation therapy served as the primary endpoint. Secondary endpoints included rate of conversion to mastectomy, cosmetic outcome and adherence to protocol radiation.

Median follow-up was 66.4 months (range, 1.3-90.6).

Results

Six women developed local recurrence, including four in the ipsilateral breast, one skin and one in the ipsilateral chest wall. This equated to an estimated cumulative incidence of local recurrence of 3.1% (95% CI, 1.3-6.4) at 5-year follow-up.

Researchers also identified six contralateral breast cancers, four patients with distant disease and three new nonbreast cancer primaries. Eight patients died, including one associated with breast cancer.

Researchers reported a 1.7% (HR = 1.0; 95% CI, 0.6-5.2) local recurrence rate at 5 years among 189 women who underwent preoperative MRI compared with a rate of 22.6% (HR = 13.5; 95% CI, 7.9-55.1) among 15 women who did not undergo preoperative MRI (P = .002).

Results additionally showed a 5-year estimated local recurrence rate of 2.6% (95% CI, 1.0-6.8) among women with ER-positive, HER2-negative disease.

Researchers acknowledged study limitations, including the single-arm design, small subset of patients with no preoperative MRI, and short follow-up for ER-positive disease.

“This study provides important data for surgeons and radiation oncologists to discuss with their patients who have two or three foci of breast cancer in one breast and allows patients to consider their preference between breast conservation therapy and mastectomy,” Boughey said.

“Breast-conservation therapy is often preferred to mastectomy, as it is a smaller operation with quicker recovery and results in better patient satisfaction and cosmetic outcomes,” she added. “We hope that this will provide patients with multiple ipsilateral breast cancer [information] to consider breast-conserving therapy if they are interested.”