Patients with multiple tumors in a single breast who underwent a lumpectomy followed by radiation therapy had local recurrence rates comparable to those historically observed in patients with a single tumor, according to new findings presented by Judy C. Boughey, MD, and colleagues at the 2022 San Antonio Breast Cancer Symposium (Abstract GS4-01).
Judy C. Boughey, MD
Background
“Most patients who present with two or three sites of cancer in one breast are recommended to undergo a mastectomy, as historical studies showed high local recurrence rates in patients who underwent breast-conserving therapy consisting of lumpectomy and radiation therapy,” explained Dr. Boughey, the W.H. Odell Professor of Individualized Medicine and Chair of the Division of Breast and Melanoma Surgical Oncology at the Mayo Clinic.
“Advances in imaging techniques have led to greater detection of additional breast tumors, leading to more patients undergoing mastectomy who otherwise may have preferred breast-conserving therapy,” Dr. Boughey added. “To date, there have been no prospective clinical trials evaluating local recurrence after breast-conserving therapy for patients with multiple ipsilateral breast lesions. The main purpose of this trial was to evaluate whether a lumpectomy followed by radiation therapy was an appropriate management for patients who had more than one tumor in a single breast.”
Study Methods and Results
The ACOSOG Z11102 (Alliance) prospective phase II clinical trial enrolled patients older than age 40 who had two or three sites of breast cancer in the same breast, separated by normal breast tissue. All patients had undergone mammogram and/or ultrasound, and most had undergone breast magnetic resonance imaging (MRI) as well. Of the trial participants, 14 converted to mastectomies as a result of persistent positive margins, which precluded breast-conserving therapy. The remaining patients were treated with lumpectomies and subsequent whole-breast radiation therapy, with radiation boosts to all lumpectomy sites. The primary endpoint of the study was local recurrence at 5 years after the completion of radiation therapy.
Among the 204 evaluable patients, 6 developed local recurrence after a median follow-up of 66.4 months, for a 5-year local recurrence rate of 3.1%—a rate similar to the local recurrence rates seen in prior studies for patients with a single breast tumor who underwent breast-conserving therapy.
The rate of local recurrence was higher among the 15 patients who did not undergo a presurgical breast MRI compared with the 189 patients who underwent this imaging (22.6% vs 1.7%). Dr. Boughey noted this may have been the result of greater disease site detection prior to surgery in patients who underwent breast MRI—potentially allowing for more thorough resection. The risk of local recurrence was not associated with patient age, number of breast lesions, tumor biology, or pathologic staging categories.
No patients developed regional recurrence. However, four patients developed distant recurrence, six patients developed breast cancer in the opposite breast, three patients developed new nonbreast primary tumors, and eight patients died—including one death related to breast cancer.
Clinical Conclusions
“This study provides important information for clinicians to discuss with patients who have two or three foci of breast cancer in one breast, as it may allow more patients to consider breast-conserving therapy as an option,” underscored Dr. Boughey. “Lumpectomy with radiation therapy is often preferred to mastectomy, as it is a smaller operation with quicker recovery, resulting in better patient satisfaction and cosmetic outcomes.”
Dr. Boughey added that the results from the trial also suggested that patients diagnosed with two or more malignant lesions in the breast and considering breast-conserving therapy may benefit from breast MRI.
A limitation of the study was its single-arm design. “While a randomized trial design would have provided stronger data, we felt that accrual to such a design would be problematic, as many patients and surgeons would not be willing to randomize,” noted Dr. Boughey.
The researchers concluded that for patients with multiple ipsilateral breast cancer, breast-conserving surgery with adjuvant radiation with lumpectomy site boosts may be a reasonable consideration for those with two to three tumor foci.
Disclosure: The research in this study was supported by the National Institutes of Health. Dr. Boughey has received funding for other studies from Eli Lilly and Company, Symbiosis Pharma, CairnSurgical, UpToDate, and PeerView.
