Many women with two or three cancerous lesions in the breast can safely undergo lumpectomy followed by radiation therapy, according to the results of a prospective phase II trial reported at the 2022 San Antonio Breast Cancer Symposium.1 In this study, local recurrence rates after breast-conserving surgery (lumpectomy) plus radiation therapy were similar to those observed in patients with a single tumor treated similarly. The cumulative incidence rate of local recurrence was 3.1% at 5 years. The results also suggest that presurgical breast magnetic resonance imaging (MRI) may improve outcomes because of more precise identification of sites of disease in the breast.
“Most patients who present with two or three sites of cancer in one breast are recommended to undergo a mastectomy, as historical studies have shown high local recurrence rates in patients who underwent breast-conserving therapy consisting of lumpectomy and radiation therapy,” said presenting author Judy C. Boughey, MD, Professor and Chair of the Division of Breast and Melanoma Surgical Oncology, Mayo Clinic, Rochester, Minnesota.
Judy C. Boughey, MD
“Advances in imaging techniques have let to greater detection of additional tumors, leading to more patients undergoing mastectomy who might otherwise have preferred breast-conserving therapy. 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 the trial was to evaluate whether lumpectomy followed by radiation therapy was appropriate management for patients who had more than one tumor in a single breast,” Dr. Boughey.
Study Details
The study enrolled 270 patients. Of them, 34 were ineligible, 14 converted to mastectomy, 2 did not achieve negative margins, and 16 withdrew before completing treatment, leaving 204 patients who completed breast-conserving surgery and radiation therapy. Women enrolled had to be older than age 40 and have undergone mammography and/or ultrasound to determine the number of lesions. Most patients also had presurgical MRI. Lesions had to be separated by normal tissue and limited to two quadrants of the breast. Neoadjuvant therapy was not allowed. Patients were treated with lumpectomy resected to negative surgical margins followed by whole-breast irradiation with a radiation boost to lumpectomy beds.
At a median follow-of 66.4 months, six patients developed local recurrences (four in the ipsilateral breast, one in the breast skin and one in the chest wall), corresponding to an estimated cumulative 5-year risk rate of local recurrence of 3.1 %. Dr. Boughey pointed out that this is similar to the rate seen in prior studies of women who underwent breast-conserving therapy for a single lesion.
In addition, the local recurrence rate was higher among 15 patients who did not have a presurgical MRI compared with 189 patients who did have presurgical MRI: 22.6% vs 1.7%, respectively. Dr. Boughey said this could be attributable to improved detection of sites of disease, allowing for more targeted resection. Factors that were not associated with local recurrence included patient age, number of breast lesions, tumor biology, or pathologic staging categories.
No patient in the study had a regional recurrence, but four patients developed distant recurrence, and six developed cancer in the contralateral breast, three developed new nonbreast primary tumors, and eight patients died (one death was attributable to breast cancer).
“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,” Dr. Boughey told the audience. “Lumpectomy plus radiation is often preferred to mastectomy, as it is a less invasive operation with quicker recovery, resulting in better patient satisfaction and cosmetic outcomes.”
Dr. Boughey noted that the study would have had more power if it had been randomized. However, she added, it would be difficult (if not impossible) to accrue patients to such a study.
Additional Commentary
Aditya Bardia, MD, MPH
Breast medical oncologist Aditya Bardia, MD, MPH, Associate Professor, Medicine, Harvard Medical School, Massachusetts General Hospital, Boston, commented on these study findings: “This is an important study that evaluated the role of lumpectomy in patients with multiple ipsilateral tumors. The rate of local recurrence was low, suggesting breast-conservating surgery could be considered safely in this setting. The study highlights the importance of obtaining breast MRI to evaluate the extent of disease in the setting of multiple lesions, and broadly how even single-arm studies can provide meaningful contributions to the field.”
DISCLOSURE: The study was funded by the National Institutes of Health. Dr. Boughey has received research fundings from Eli Lilly and Company, Symbiosis Pharma, Cairn Surgical, UpToDate, and PeerView. Dr. Bardia has served as a consultant or advisor to Genentech/Roche, Immunomedics/Gilead Sciences, Novartis, Pfizer, Merck, Radius Health, Foundation Medicine, Sanofi, AstraZeneca, Daiichi Sankyo, and Eli Lilly; and has received institutional research funding from Genentech, Novartis, Pfizer, Merck, Sanofi, Radius Health, Immunomedics/Gilead Sciences, Daiichi Sankyo/AstraZeneca, Eli Lilly, Natera, and Mersana.
REFERENCE
1. Boughey JC, Rosenkranz KM, Ballman KV, et al: Impact of breast conservation therapy on local recurrence in patients with multiple ipsilateral breast cancer: Results from ACOSOG Z11102 (Alliance). 2022 San Antonio Breast Cancer Symposium. Abstract GS4-01. Presented December 9, 2022.
