Breast-conserving therapy may be viable option for multiple ipsilateral breast cancer
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SAN ANTONIO — 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.”
Perspective
Back to TopLinda M. Pak, MD
This study provides important information regarding the oncologic safety of performing breast-conserving surgery for patients with two to three areas of breast cancer in one breast. The results show it is safe to offer these patients breast conservation, thereby allowing us to expand the indications for breast conservation. Breast-conserving surgery is a much smaller surgery than mastectomy. Patients who undergo breast-conserving surgery are able to go home the same day after surgery and have a much faster recovery period. This is exciting to see, as it provides important information that breast-conserving surgery is safe for these patients. We can now share the results of this study with patients when we discuss their surgical options with them. The strength of this study is the prospective design and the length of follow-up time (median, 66 months). I hope this will make more breast surgeons and patients comfortable with this approach and increase the use of breast conservation among these patients.
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Boughey JC, et al. Abstract GS4-01. Presented at: San Antonio Breast Cancer Symposium; Dec. 6-10, 2022.
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