Abstract 4914: Pregnancy and breast cancer outcomes

Background: Pregnancy-associated breast cancer (PABC) poses a unique challenge as hormonal changes occurring in pregnancy potentially interact with breast cancer outcomes. However, reports on prognosis of PABC have been rare and inconsistent, and most of these studies were from Western countries with only few from Asia. We investigated the outcome of PABC linking a large hospital-based database and the nationwide claims database of Korea. Patients and methods: We retrospectively studied a cohort of 3687 female patients of reproductive age ( Results: Among 3687 patients, 18 and 45 patients were classified as having breast cancer during pregnancy and postpartum breast cancer, respectively, comprising 63 cases of PABC. Patients with PABC were significantly more likely to have advanced stage and/or hormone receptor negative tumor, and be younger than 35 years old at diagnosis of breast cancer than those without it (P value for T stage, .0001; N stage, .0011; ER negativity, Conclusions: PABC and postpartum breast cancer tended to be associated with higher stage, hormone receptor negativity, and thus worse survival, but breast cancer during pregnancy had no adverse effect on survival in patients with breast cancer. Note: This abstract was not presented at the meeting. Citation Format: Mihong Choi, Jiyeon Han, Bo Ram Yang, Myoung-jin Jang, Miso Kim, Tae-Yong Kim, Seock-Ah Im, Han-Byoel Lee, Hyeong-Gon Moon, Wonshik Han, Dong-Young Noh, Kyung-Hun Lee. Pregnancy and breast cancer outcomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4914.