Optimizing the Treatment for Pregnancy-Associated Breast Cancer: a Case Example and Review of the Literature

Purpose of ReviewBreast cancer is the most common malignancy affecting women throughout the world, and accounts for 30% of new cancer diagnoses in women with overall lifetime risk hovering around 1/9. Pregnancy-associated breast cancer (PABC) is defined as breast cancer diagnosed during pregnancy or within 12 months of delivery. While accounting for up to 7% of cancers in women younger than 45, incidence is variable, with a higher preponderance among those with positive family history or a deleterious BRCA mutation. In this review, we provide a comprehensive overview of the epidemiology, diagnosis, and treatment paradigm for PABC, and discuss a case in order to bring out additional discussion of locoregional and systemic therapeutic options and importance of shared decision-making in these difficult situations.Recent FindingsA breast mass that has persistent beyond 2 weeks in pregnancy should be further evaluated, and breast ultrasound is the recommended initial imaging modality. If suspicion for a neoplastic process persists, mammography should be performed. Surgical recommendations for PABC are similar to non-pregnant patients in regard to clinical stage, tumor biology, genetic testing, and surgical desires; radiation is contraindicated until after delivery. Many studies have demonstrated safety of select chemotherapy agents for the treatment of PABC when administered beyond the first trimester, and when neoadjuvant or adjuvant chemotherapy is indicated, combinations including anthracyclines and taxanes have the most robust safety data when employed beyond 12-week gestation. Based on current data, albeit largely derived from animal studies, other systemic therapy options including endocrine therapy, HER2-directed therapies, immunotherapy, CDK 4/6 inhibitors, and PARP inhibitors are contraindicated and should be held until the postpartum setting.PABC represents a unique challenge requiring a multidisciplinary approach among medical specialists. Treatment planning should implement a patient-centered approach with the overall goal of maximizing the opportunity for the best breast cancer outcome while minimizing the risk of fetal harm.