Importance of a Multidisciplinary Approach to Breast Cancer Treatment in Pregnancy: Case Report of New Diagnosis of Pregnancy-Associated Breast Cancer

Pregnancy-Associated Breast Cancer (PABC) is a rare diagnosis and includes new diagnoses of cancer both during pregnancy as well as within the first year post-delivery. Due to its rarity, there is of yet no gold standard treatment nor is there a standardized regimen of treatment during pregnancy according to the American College of Obstetrics and Gynecology (ACOG). We report a case involving a 35-year-old gravida 2 para 1-0-0-1 who was diagnosed with clinical stage II (T2 N1) breast cancer in the early third trimester of pregnancy after physical examination revealed a palpable mass. Ultrasound-guided biopsy revealed poorly differentiated infiltrating ductal carcinoma, nuclear grade 3, with micropapillary features, estrogen receptor (ER 90%), progesterone receptor (PR 25%) positive, HER2 positive 3+ with Ki67 index 75%. After extensive counseling and discussion between Obstetrics, Maternal Fetal Medicine, Breast Surgery, Neonatal ICU, and Oncology, a decision was made to initiate neoadjuvant chemotherapy (NAC) with adriamycin and cyclophosphamide. Our patient completed 4 total NAC treatments prior to delivery followed by a regimen of weekly taxol plus herceptin and perjeta postpartum. This patient strongly desired to carry the pregnancy to term and began treatment prior to delivery, making this case unique in comparison to other publications in which treatment was delayed until after delivery, or the pregnancy was terminated prior to beginning treatment. Our case highlights the importance of a multi-disciplinary approach to counseling patients in this unique situation to allow them the autonomy to choose the treatment best for them and their baby.