Impact of timing of pregnancy and genetic risk on local therapy choices for young women with breast cancer

It is unknown whether timing of pregnancy before, during, or after breast cancer (BC) is associated with surgical choices in young women with breast cancer. A retrospective chart review identified patients who had a pregnancy within 5 years prior to breast cancer diagnosis (PpBC), were pregnant during breast cancer diagnosis (PrBC), or had a pregnancy within 5 years after BC diagnosis (SPBC). Chi-square test and logistic regression analysis were used to compare surgical choice—unilateral surgery (ULS) or bilateral mastectomy (BM)—between groups. Of 109 women, 36 (33.0 ​%) had PpBC, 18 (16.5 ​%) had PrBC, and 55 (50.5 ​%) had SPBC. 42.2 ​% had stage II BC and 31.2 ​% had triple negative BC (TNBC). 100 patients had genetic testing and 30 (30 ​%) had a germline pathogenic mutation. Overall, 49.5 ​% of women underwent BM, and this was similar between groups. On logistic regression, genetic mutation (OR 5.44, p ​= ​0.003) and ER-negative tumor subtype (TNBC OR 11.9, p ​= ​0.017; ER-/HER2+ OR 23.2, p ​= ​0.015) were associated with higher rates of BM. In this study, approximately half of women with pregnancy within 5 years of BC diagnosis underwent BM. Genetic predisposition and ER-negative tumor subtype was predictive of this choice while timing of pregnancy was not. •Half of young women with breast cancer undergo bilateral mastectomy.•Genetic risk and ER-negative subtype are factors associated with surgical choice.•Timing of pregnancy does not seem to impact choice for bilateral mastectomy.