Pregnancy-associated breast malignancy mostly presents with an aggressive type of breast cancer

Published reports on the prognosis of pregnancy-associated breast cancer are controversial. This study aims to determine the histopathological features of pregnancy-associated breast carcinoma (PABC) and the outcomes of patients with breast cancer during pregnancy and lactation among Turkish women. The study retrospectively analyzed 29 patients diagnosed with pregnancy-associated breast malignancies who underwent surgery between January 1989 and March 2021. Demographic and pathological data were obtained to evaluate the clinicopathological and prognostic characteristics of the patients. The median age was 36 years (range: 26-42 years). Of the 29 patients with breast cancer, 13 (44.8%) were diagnosed during pregnancy, and the remaining 16 (55.2%) were diagnosed during lactation. Most patients had clinical tumor stage (cT) cT2-3 (n = 20, 69%) disease, and 15 patients had clinically node (cN)-positive disease (N1 and N2, 51.7%). The majority (n = 19, 65.5%) had invasive ductal carcinoma with high Ki-67 scores (>20%). Patients with lactation-associated breast cancer were more likely to have a family history of breast cancer (44% vs. 8%, p = 0.04) than those with pregnancy-associated breast cancer. Notably, symptom duration >= 6 months and presenting with cT3-4 or cN(+) disease were associated with poor disease-free and disease-specific survival. However, no difference could be found in outcome among patients with pregnancy- and lactation-associated breast cancer. PABC mostly presents with aggressive tumor molecular subtypes with high Ki-67 scores and more advanced stages associated with poor outcome, possibly due to delayed diagnosis. Therefore, prompt early diagnosis and awareness of this disease might improve survival.