Chemotherapy and Optimal Timing of Delivery for Women with Triple Negative Breast Cancer [16D

Abstract

INTRODUCTION: Data are limited regarding the optimal management of breast malignancy in pregnancy, particularly for the more aggressive subtype of triple negative breast cancer (TNBC). We sought to compare strategies for the management of TNBC and to determine the optimal gestational age for induction in regards to chemotherapy status and maternal-fetal outcomes. METHODS: A decision-analytic model was designed for women with TNBC at 20 weeks electing to continue their pregnancies, comparing 32 different strategies for scheduled delivery between 24-39 weeks gestation, with chemotherapy induction either at 24 weeks or delayed until after delivery. Baseline estimates of stage-specific mortality and the impact of delayed cancer treatment on 5-year survival rates were obtained from the literature. Outcomes factored into the model included the risk of intrauterine fetal demise, spontaneous delivery, respiratory distress syndrome, cerebral palsy, and neonatal demise at each gestational age. RESULTS: For women assigned to antepartum chemotherapy, overall QALYs were maximized with delivery at term, with minimal additional benefit beyond 37 weeks. For women with TNBC deferring chemotherapy until the postpartum period, 5-year survival was maximized by immediate delivery, although maternal QALYs were maximized with delivery at 36 weeks for stage I, 31 weeks for stage II, and 26 weeks for stage III disease. Our model was heavily driven by the baseline probability of maternal death within 5 years, in addition to the expected progression of disease and decrease in survival rates with each week of non-treatment, and remained robust across reasonable ranges for all variables of interest. CONCLUSION: For women with TNBC diagnosed in early pregnancy, initiation of chemotherapy and delivery at 37 weeks should be considered.