Objectives: Nipple-sparing mastectomy (NSM) has become more frequently utilized due to superior psychological and cosmetic outcomes. The aim of this study was to evaluate the accuracy and utility of intraoperative frozen section evaluation of the retroareolar margin (RAM) in NSM. The management of atypical epithelial proliferative lesions at the RAM was also reviewed and discussed.
Methods: A single institution, retrospective analysis was performed on all therapeutic NSM patients with intraoperative evaluation of the RAM from 2014 to 2018. Patient demographics, tumor characteristics, pathologic assessment of the RAM, surgical management, and clinical follow-up were reviewed.
Results: Seventy-four nipple-sparing mastectomies with intraoperative evaluation of RAMs were identified. Concordance was 95% between frozen and permanent section diagnoses with 4 cases representing false negatives and no false positives. There were no instances of nipple-areolar complex (NAC) recurrence in all cases with preserved NACs (mean follow up: 750 days). In the 9 cases where NACs were excised based on intraoperative RAM evaluation, the findings in the excised NACs were negative in 6 and ductal carcinoma in situ in 3 cases. Postoperative measurement of the tumor to nipple distance was the only statistically significant variable associated with a positive RAM by multivariable logistic regression (OR 0.475; 95% CI 0.238-0.946).
Conclusions: Intraoperative RAM evaluation demonstrated high concordance with permanent histology. Negative RAM, including atypical epithelial proliferative lesions, led to NAC preservation without recurrence. Positive RAM alone did not predict NAC involvement, although pagetoid spread of ductal carcinoma in situ along nipple ducts may predict NAC positivity.
Keywords: Frozen Section; Mastectomy; Nipple-Sparing; Retroareolar Margin.
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