Retrospective cross-sectional analytical study on pregnancy-associated breast cancer in patients treated at a cancer center

Introduction: Breast cancer is the second most common malignant neoplasm among women in Brazil and worldwide. It is considered pregnancy-associated when the malignant tumor occurs during pregnancy and up to the first year after delivery. However, current studies show an increased prevalence of these cases, and their causality is not yet well explained. Objective: The aim of this study was to perform a descriptive analysis of the profile of patients with breast cancer during pregnancy treated at our facility from 2010 to 2020. Methods: This retrospective cross-sectional study analyzed electronic health records from a database. The sample consisted of pregnant or postpartum patients diagnosed with breast cancer and treated at AC Camargo Cancer Center from 2010 to 2020. Variables were described based on absolute and relative frequency distributions. Statistical analysis was performed using the Mann-Whitney U test and the independent samples Kruskal-Wallis test. Results: The final sample comprised 44 patients. The mean age was 35 years. Most patients had no comorbidities, were married, white, and had access to the service through health insurance (95.5%). Ductal carcinoma was the most prevalent (84.1%). The main molecular subtypes were luminal B without HER2 expression (34.1%) and triple negative (25%). About 30% of the cases were associated with some genetic mutation. Most patients were diagnosed in the postpartum period (70.5%). Recurrence occurred in five cases. We found four cases of death, three of which had oncological causes. The comparative analysis of variables that could lead to worse prognosis, such as genetic mutation and molecular subtypes, did not indicate a higher recurrence of cases, since they were not statistically significant. Conclusion: The profile of patients with pregnancy-associated breast cancer treated at this cancer center partly follows the trend of other centers.