Risk of locoregional recurrence in patients with false-negative frozen section or close margins of retroareolar specimen in nipple-sparing mastectomy.

Background: Our purpose was to evaluate the locoregional recurrence (LRR) of patients with false-negative, frozen-section or close margins of retroareolar specimen in nipple-sparing mastectomy (NSM) procedure.
Methods: From 2002-2008, we recruited patients who had atypia or presence of cancer cells in definitive histology of retroareolar tissue despite of absence of tumor cell in intraoperative retroareolar frozen section. We also included the close margin cases defined as the presence of tumor cells at the first frozen section, but after deeper core out of retroareolar tissue were revealed free of malignancy. The incidence of LRR and NAC recurrence were reported, and the factors associated were analyzed.
Results: Of 948 NSM procedures, there were 88 false-negative, frozen-sections and 10 close margin cases. The 5-year cumulative incidence of LRR and NAC recurrence was 11.2 % (10/98 patients) and 2.4 % (2/98 patients), respectively. Analyzing the definitive results of retroareolar tissue, the 5-year cumulative incidence of LRR was 42.9 % (n = 4) for atypia, 10 % (n = 2) for lobular carcinoma in situ (LCIS), 10 % (n = 1) for close margins, 8.7 % (n = 3) for ductal carcinoma in situ (DCIS), and 0 % for invasive carcinoma. In situ carcinoma as a primary tumor was a significant predictor of NAC recurrence (P < 0.01).
Conclusions: Despite a high reliability of frozen section, there is still a minority of false-negative results. Nevertheless, the LRR is considerably low. This fact suggests the possibility of preservation of the NAC after discussion with the patient.