First Reported Case of Successful Conception and Delivery During Stage IV Breast Cancer Treatment: A Case Report and Literature Review

We herein report a case involving a woman with metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) who became pregnant while undergoing active anticancer therapy with Trastuzumab-Pertuzumab for her advanced BC disease at our institution. To our knowledge, this is the first reported case of pregnancy and successful delivery in a stage IV BC patient during anticancer therapy. A multidisciplinary approach for such a complex case is a must to evaluate the mother's medical condition by an experienced oncology team along with a maternal-fetal team, with support from a psychiatric and psychological evaluation for the mother. The use of effective contraception during anticancer therapy is essential to avoid such a scenario.