AB052. SOH24AB_203. Sentinel lymph node biopsy in patients undergoing risk reduction mastectomy: a systematic review and meta-analysis

Background: Prophylactic mastectomy is offered to women in the high risk setting to reduce the real or apparent risk of future breast cancer. The utility of performing a sentinel lymph node biopsy (SLNB) at the time of mastectomy remains controversial, with no uniform guidelines available. We performed a systematic review and meta-analysis to assess the benefit, if any, in performing a SLNB during prophylactic mastectomy.

Methods: A systematic review was conducted as per the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Characteristics predictive of SLNB+ were assessed as dichotomous variables, expressed as odds ratio (OR) with corresponding 95% confidence interval (CI) using the Mantel-Haenszel method. Further analysis, either fixed or random effects models were applied on the bases of whether significant heterogeneity (I²>50%) existed.

Results: A total of 16 studies involving 4,789 patients were included in our study. The total number of mastectomies performed was 3,670. Of these 3,670 mastectomies, a total of 327 prophylactic mastectomies were performed for BRCA (breast cancer gene) positive patients, with the remaining 3,343 mastectomies performed for risk reducing purposes (high risk lesions, positive family history, history contralateral disease). And 360/2,828 (12%) of patients had a SLNB performed, of which 38/2,828 (1.3%) were found to have a positive result (OR: <0.01, 95% CI: 0.00–0.01, P<0.0001, I²=39%).

Conclusions: Routine use of SLNB in patients undergoing prophylactic mastectomy may not be indicated due to low levels of positivity as well as additional morbidity.

Keywords: Breast; mastectomy; prophylactic; risk reducing; sentinel node