The Role of Sentinel Node Biopsy in Women Undergoing Prophylactic Mastectomy

Background Sentinel lymph node (SLN) biopsy in patients undergoing prophylactic mastectomy (PM) remains controversial. We sought to determine the incidence of finding occult cancer and the frequency of SLN positivity in patients undergoing contralateral PM. Methods Medical records of patients undergoing bilateral mastectomy at our institution from 2003 to 2008 were reviewed ( n = 115). Eight patients (6.9%) had known bilateral cancer; an additional eight patients (6.9%) underwent BPM for risk reduction. The remaining 99 patients who had ipsilateral breast cancer and underwent contralateral PM formed the cohort of interest for this study. Univariate and multivariate analyses to determine factors correlating with occult malignancy and SLN positivity in the PM specimen were performed using SPSS ver. 17 (SPSS Inc., Chicago, IL). Results The median patient age was 50 y, and median ipsilateral tumor size was 1.7 cm. Occult contralateral malignancy was found in eight (8.1%); of these, six (75.0%) had DCIS only. A positive SLN was found on the prophylactic side in 2 (2.0%) patients. Both had ipsilateral inflammatory cancer, and over 15 positive ipsilateral lymph nodes post-neoadjuvant chemotherapy. Ipsilateral inflammatory breast cancer was correlated with the finding of invasive cancer in the contralateral PM ( P = 0.006), and both the finding of ipsilateral inflammatory breast cancer and number of positive lymph nodes correlated with the finding of a positive contralateral SLN. Conclusion The incidence of occult malignancy in PM is low (2%). However, patients with ipsilateral inflammatory cancer are at high risk of contralateral malignancy; SLN biopsy on the prophylactic side in these patients may be warranted.