Re-excision to achieve wider disease-free tumor margins can be reconsidered for certain women treated with lumpectomy for ductal cancer in situ (DCIS), the earliest stage of breast cancer, according to a study recently presented at the American Society of Breast Surgeons Annual Meeting.
The study analyzed data from NSABP/NRG Oncology B-35, a large randomized trial evaluating endocrine therapy, which also prospectively collected margin width data. The study focused on post-menopausal women with hormone receptor-positive DCIS treated with breast-conserving surgery, whole breast irradiation, and post-operative endocrine therapy. At 10 years post-surgery, researchers found no clinically meaningful differences in cancer recurrence in the same breast for patients whose tumors had margins equal to or greater than 1mm and margins equal to or greater than 2mm, suggesting that wider margins did not provide a benefit.
Lead study author Irene L. Wapnir, MD, Professor of Surgery and Surgical Oncologist at Stanford Medicine, explains, “In lumpectomy surgeries, the goal is to remove a tumor surrounded by a rim of normal breast tissue to minimize leaving cancer tissue behind. The current recommendation for patients with DCIS undergoing lumpectomy is a 2mm disease-free margin. If margins are found to be less than 2mm, women often return to the operating room to remove additional tissue from the lumpectomy cavity. This study is extremely important because it suggests a re-examination of the need for re-excision.”
The NSABP B-35 trial examined two hormone therapy drugs for use with this DCIS population following breast-conserving surgery. It also prospectively collected data on margin width. All women in this multi-center study were treated with lumpectomy between 2003 and 2006. They were followed for a median of 9 years post-surgery.
With little difference in disease-free survival between the two endocrine therapy cohorts, the double-blind phase 3 trial provided a powerful, homogeneous population for secondary analysis to study the impact of margin width on local recurrence.
“To our knowledge, this research uses the largest dataset of margin width and recurrence in this cancer population,” says Dr. Wapnir.
Researchers analyzed 2,707 women to compare local recurrence among patients with margin widths less than 1mm to those with margins equal to or greater than 1mm. The 10-year cumulative incidence of cancer recurrence in the same breast for the two groups was 5.6% and 4.0% respectively.
The study also looked at 2,546 women to compare the 10-year cumulative incidence of local recurrence in patients with margin widths less than 2mm and margins equal to or greater than 2mm. These were 5.3% and 3.8%, respectively.
Similar to the 1mm cutoff analysis, the 2mm analysis found the absolute difference in local recurrence was 1.5%, but of borderline statistical significance and minimal practical significance.
Dr. Wapnir and colleagues believe that clinicians should consider whether such a small difference in recurrence merits repeat surgery. “For patients, re-operation and removal of more breast tissue can impact cosmetic appearance and can contribute to stress, loss of time and expense. It also utilizes greater healthcare resources.” She adds, “The results of this study are compelling, and we hope will improve patients’ lives.”
– By Jeanne Phillips
Jeanne Phillips is managing editor of HealthTech HotSpot and an experienced healthcare writer and content creator with more than 15 years of experience. Her articles have appeared in a wide range of highly regarded consumer and professional healthcare publications and have focused on medical science, wellness, healthcare technology, pharmaceuticals, economics, and much more. She has interviewed well-known medical experts worldwide for major stories and ghostwritten articles for leading physicians. Ms. Phillips also develops healthcare content ranging from advertisements and white papers to e-books, social media posts, and blogs.
