Clinicopathological characteristics and prognosis of pregnancy-associated breast cancer: a multicenter retrospective study from the central China

Abstract Purpose: This study aimed to compare the demographic and clinical characteristics of pregnancy-associated breast cancer (PABC) and non-PABC patients, and to analyze the prognostic factors. Methods: PABC patients ≤ 40 years old who were treated in three large tertiary institutions from January 1, 2016 to August 1, 2020 were included. The population and tumor characteristics of the patients were collected, and their survival were followed up. For each case, a non-PABC patient was matched as a control. Results: A total of 69 PABC patients and 69 non-PABC patients were included in the study. Compared with the non-PABC group, the clinical stage of PABC patients was later. In the univariate and multivariate analysis of all patients with breast cancer, it was found that the prognosis of PBAC patients was worse than that of controls and pregnancy correlation was not an independent factor affecting the prognosis of breast cancer. Moreover, there was no significant difference in clinicopathological characteristics between pregnancy and postpartum breast cancer. In the analysis of prognostic factors of PABC patients, we found that gestational weight gain (GWG) and vascular invasion were important factors affecting disease-free survival (DFS) of PABC patients, while oral contraceptive and clinical stage were important factors affecting their overall survival (OS). Conclusions: The prognosis of PABC patients was worse. However, pregnancy correlation was not an independent factor affecting the prognosis of breast cancer patients. Vascular invasion and inadequate or excessive gestational weight gain were important factors affecting recurrence and metastasis in PABC patients. Generally speaking, it is necessary to pay more attention to weight gain during pregnancy.