Biology, care, and outcomes of gestational breast cancers: a review.

Objective: The incidence of gestational breast cancers, breast cancers diagnosed during pregnancy, is increasing. There is a critical need to understand the pathophysiology, treatment recommendations, and remaining questions regarding care and therapeutics for this complex condition.

Methods: Here, we review existing data regarding evaluation and management of gestational breast cancer, including safe imaging modalities, timing and choice of chemotherapy, evidence regarding targeted therapies during pregnancy. We highlight the importance of multidisciplinary care including oncologic, obstetric, and psychosocial care.

Results: Gestational breast cancers are associated with unique biologic and clinicopathologic features that are impacted by physiologic changes of pregnancy such as upregulation of target genes associated with cell proliferation and immune regulation. Patients with gestational breast cancers more often present at advanced stages, are more likely to have aggressive tumor subtypes (i.e., triple negative or HER2 positive), and overall have worse prognoses than patients with non-gestational breast cancers. In this review, we synthesize recommendations for treatment strategies based on pregnancy trimester, optimal timing and choice of surgery, chemotherapy, targeted therapies, and psychosocial support.

Conclusions: Developing a framework for clinical care and treatment of patients with gestational breast cancers is integral to improving outcomes for patients with gestational breast cancers. Optimal treatment includes collaborative management with a multidisciplinary team dedicated to both maternal and fetal care.