Managing Positive Nipple Margins in Nipple-Sparing Mastectomy
A STUDY FROM THE MASSACHUSETTS GENERAL HOSPITAL
Patients were identified who underwent nipple-sparing mastectomy (NSM) and were found to have atypia or tumor in their nipple-margin. These patients were identified from a prospectively maintained single-institution database of NSMs.
From June 2007 to August 2019, 3158 NSMs were identified. Tumor was found in 117 (3.7%) patients and atypia only in 164 (5.2%) patients. Considering the 117 patients with tumor in their margin, 80 (68%) contained DCIS, 34 (29%) contained invasive tumor, and 3 (3%) had lymphatic vessel invasion only.
MANAGEMENT
Management included nipple excision only in 67 (57%) breasts, nipple-areola complex (NAC) excision in 35 (30%), and no further treatment in 15 (13%). Only 23 (24%) of nipples were found to have residual tumor. Median follow-up was 67 months. In that time there were 2 (1.8%) recurrences in the areola or peri-areola skin, both in patients with nipple-only excisions.
In the 164 patients whose margins contained only atypia, 154 (94%) of nipples were retained. At 60 months of follow-up no patient with atypia alone had a nipple or areola recurrence.
CONCLUSIONS
In the largest study to date examining oncologic outcomes in patients undergoing NSM who were found to have tumor or atypia in the nipple or areola margin. The researchers “found a very low rate of local recurrence when positive nipple margins were treated with nipple excision as a second procedure and in selected cases with observation alone.” The authors noted prior concerns in attempts to identify risk factors for nipple involvement to restrict eligibility for NSM. According to the authors, their data suggested a different approach. They suggest that NSM be attempted in any patient with no direct involvement of the nipple on examination or imaging and excise nipples with positive margins on final histopathology. They do not advocate a frozen section as they have previously noted that artifacts from freezing could make it difficult to distinguish benign atypia from DCIS potentially resulting in unnecessary nipple removal. They also noted “the low rate of recurrence with delayed excision in our series and our low rate of recurrence observed with delayed excision in our series and our demonstration that no intervention is required for atypia alone supports a cautious approach to nipple removal based on frozen section”.
The authors noted that early in their experience they excised the entire NAC when nipple margins were positive. They eventually found that only a minority of excised NACs contained tumor. Now they excise only the nipple, leaving the areola in place. They believed that 3% recurrence in the areola or peri-areola skin was acceptable but that excision of the entire NAC depended on the histopathologic findings. Though some believe that LCIS constitutes a positive margin, this “study provides strong evidence that nipple margins containing atypia including LCIS can be safely retained.”
Addendum anecdote: Rules may not always be perfect. Several years ago, I performed bilateral NSM for LCIS. Nipple margins clear but close. Several years later (approximately 5-7) she recurred with a small erosion at tip of nipple, biopsy showing LCIS. NAC excision was performed and she is well many years later.
– Alan Stolier
Dr. Alan Stolier, MD, FACS, clinical breast oncologist, shares his expert medical perspective with a series of educational and scientific articles.