The diagnostic utility of preoperative breast magnetic resonance imaging (MRI) and/or intraoperative sub-nipple biopsy in nipple-sparing mastectomy.

ABSTRACT

BACKGROUND: The necessity of routine sub-nipple biopsy was uncertain, and the role of preoperative magnetic resonance imaging (MRI) in detecting nipple invasion in patients who have been selected for nipple sparing mastectomy (NSM) has not been adequately evaluated. METHODS: We retrospectively collected and analyzed the medical and surgical records of 434 patients with primary operable breast cancer who met the criteria for NSM and underwent breast surgery during the period January 2011 to December 2015. Patients were stratified into three risk groups (low, intermediate, and high) according to tumor size and tumor-to-nipple distance. RESULTS: Among the 434 patients in this study, 29 (6.7%) had occult invasion of the nipple-areola complex (NAC). Sub-nipple biopsy had a sensitivity of 84.6%, a specificity of 100%, a false negative rate of 1.2%, a false positive rate of 0%, and an overall accuracy rate of 98.8% in confirming NAC invasion. The NAC invasion rate was 0% in the low-risk group, 5.1% in the intermediate-risk group, and 19.7% in the high-risk group (P < 0.01). The overall NPV of preoperative MRI for predicting NAC invasion was 94.8%. Cost analysis revealed that the cost of NSM with sub-nipple biopsy was significantly higher than that of NSM alone, with a mean difference in cost of USD 238.5 (P < 0.01). CONCLUSION: The high negative predictive value of MRI for NAC invasion is useful for selection of patients receiving NSM. Sub-nipple biopsy is a reliable procedure to detect occult NAC invasion, however, routine use is not cost-effect for low risk patients.