Breast cancer during pregnancy: an oncologist’s viewpoint

Background . Malignant neoplasms occur in 0.05–0.1 % of all pregnancies, breast cancer (BC) is the most common malignant neoplasm associated with pregnancy. The prognosis of this pathology remains a subject of debate due to conflicting research findings and requires a multidisciplinary approach to minimize risks for both mother and fetus. The prognosis of this pathology remains a subject of debate due to conflicting research findings and requires a multidisciplinary approach to minimize risks for both mother and fetus. Aim . Identification of problems in clinical and morphological diagnostics of pregnancy-associated BC to improve treatment outcomes. Materials and methods. This study included 35 patients over the age of 18 years with a diagnosis of breast cancer during pregnancy, who received treatment at the N.N. Petrov National Medical Research Oncology Center and the V.A. Almazov National Medical Research Center from May 2017 to March 2024. Results . The average age of patients was 35.34 ± 3.57 years. The diagnosis was established on average at 23 weeks of pregnancy, at stages II–III of the disease. 21 patients (60 %) were estrogen-receptor- and progesterone-receptornegative by the immunohistochemical subtype. Genetic mutations were detected in 30.3 % of cases. Pregnancy was terminated in 3 (8.8 %) patients. Systemic therapy during pregnancy was performed in 18 (51.4 %) patients, surgery – in 3 (8.6 %) patients, and 11 (31.4 %) women refused treatment during pregnancy and started it only after delivery. Progression of BC was detected in 8 (22.9 %) of cases. Locoregional recurrence was diagnosed in 1 (2.9 %) patient. Conclusion . The complexity of treatment and the growth of the population of patients diagnosed with pregnancyassociated BC confirm the need for analysis of individual cases, multicenter studies, and the creation of a common registry to determine clear algorithms for diagnosis and management of this pathology. For timely diagnosis of BC during pregnancy, it is necessary to conduct examinations of the mammary glands (ultrasound diagnostics) in early stages of women over 30 years of age. It is necessary to further study the division of the concepts of diagnosis of BC during pregnancy and BC during lactation (for at least 3 years after delivery) for a more accurate assessment of the prognosis of the disease and optimization of recommendations for the management of these patients.