[The role of nipple-sparing mastectomy in breast cancer: a comprehensive review of the literature]

Background: The role of nipple-sparing mastectomy (NSM) for breast cancer is controversial as there is concern regarding its oncological safety and complication rate. We carried out a review of the literature to quantify the incidence of occult nipple malignancy in breast cancer, identify the factors influencing occult nipple malignancy, quantify locoregional recurrence rates and quantify NSM complication rates.

Methods: A search of the literature was performed using PubMed. Keywords used were "mastectomy", "nipple involvement", "nipple-sparing mastectomy", "skin-sparing mastectomy" "occult nipple malignancy" "occult nipple disease" "breast cancer recurrence". Articles were analyzed regarding incidence of occult nipple malignancy, potential factors influencing the incidence of occult malignancy and recurrence/complications following NSM. The incidence of occult nipple disease was compared between groups using Chi(2) or Fisher's exact tests for categorical variables and Student's t-tests for continuous variables. P values were considered significant<0.05. We identified nearly 30 studies compiling nearly 10 000 cases examining the rate of occult nipple malignancy and 23 studies compiling 2300 cases providing information on the rate of local recurrence after NSM.

Results: The overall rate of occult nipple malignancy was 11.5 %. Primary tumour characteristics influencing occult nipple malignancy were tumour-nipple distance<2cm, grade, lymph node metastasis, lymphovascular invasion, HER2 positive, ER/PR negative, tumour size>5cm, retro-areolar/central location and multicentric tumours. The overall nipple recurrence rate following NSM was 0.9 %, skin flap recurrence rate was 4.2 %. Full and partial thickness nipple necrosis rates were 2.9 % and 6.3 % respectively.

Conclusion: NSM for primary breast cancer is appropriate in carefully selected patients. All patients should have retro-areolar sampling. There is strong evidence to suggest that suitable cases are well circumscribed single or multifocal lesions that have a TND>2cm. Tumours should be graded 1-2 and not have LVI, axillary node metastasis or HER2 positivity.