Residual cancer burden in two-stage nipple sparing mastectomy after first stage lumpectomy and devascularization of the nipple areolar complex.

Purpose: Ischemic complications after nipple-sparing mastectomy (NSM) can be ameliorated by 2-stage procedures wherein devascularization of the nipple-areolar complex (NAC) and lumpectomy with or without nodal staging surgery is performed first (1S), weeks prior to a completion NSM (2S). We report the time interval between procedures in relation to the presence of residual carcinoma at 2S NSM.

Methods: Women with breast cancer who received 2S NSM from 2015 to 2022 were identified. Both patient level and breast level analyses were conducted. Clinical staging at presentation, pathologic staging at 1S and residual disease at 2S pathology are noted. Residual disease was classified as microscopic (1-2 mm), minimal (3-10 mm), and moderate (> 10 mm).

Results: 59 patients (108 breasts) underwent 2S NSM. The median time interval between 1 and 2S for all patients was 34 days: 31 days for upfront surgery invasive cancer, 41 days for upfront DCIS surgery and 31 days for those receiving neoadjuvant therapy. Completion NSM was performed within 6 weeks for 72% of the breasts analyzed. Of the 53 breasts with invasive cancer on 1S pathology, 35% (19/53) had no residual invasive disease and 24.5% (13/53) had neither residual invasive nor in situ carcinoma on final 2S. Among the 50 women who had upfront surgery, 16 (32%) had residual invasive cancer found at 2S NSM, 9 of which had less than or equal to 1 cm disease.

Conclusion: Invasive cancers were completely resected during 1S procedure in 65% of breasts. Residual disease was minimal and there was only one case of upstaging at 2S. Added time of two-stage surgery is offset by a reduction in ischemic mastectomy flap complications.