Breast Cancer During Pregnancy: A Double Battle

Abstract

Introduction: Breast cancer is the most common neoplasia among women worldwide, with approximately 22,000 annual cases in Argentina, affecting 7% of women under 40. It originates from the uncontrolled growth of mammary tissue and, without adequate treatment, can be fatal. Early detection significantly improves prognosis and chances of cure. There are various types of breast cancer, with infiltrating ductal carcinoma being the most frequent. Risk factors are divided into non-modifiable, such as age and family history, and modifiable, including overweight, physical inactivity, and alcohol and tobacco consumption. Breast cancer is classified into five stages that determine prognosis and require appropriate treatment. In pregnant women, it is considered associated breast cancer from conception up to one year postpartum, with its incidence increasing due to delayed maternity. Treatment depends on the trimester and cancer stage, requiring a multidisciplinary approach. Surgery is safe in any trimester, chemotherapy can be administered from the second trimester, and radiotherapy is postponed until after delivery. 
Material and methods: This study is based on an exhaustive bibliographic review of the diagnosis and treatment of breast cancer during pregnancy.
 Results: This study analyzed 284 breast cancer patients, 131 of whom were pregnant, and 153 were not or were in the puerperium. The average age was 33.3 years. Among pregnant women, diagnosis occurred on average at 22 weeks of gestation, highlighting the importance of early detection. The most common symptom was a breast lump, present in 99% of patients, underscoring the need for vigilance and self-examination. Diagnostic methods included breast ultrasound in all cases, mammography in 79%, fine needle aspiration cytology in 90%, and core needle biopsy to confirm histological diagnosis. Infiltrating ductal carcinoma was the most common, present in 85.17% of cases. In molecular classification, 28% were luminal A and 23% luminal B; 39% had HER2-positive tumors, and 42% had triple-negative cancer. At diagnosis, 54% were in stages I and II, with treatments including surgery in 86%, chemotherapy in 74%, and radiotherapy in 50%. Regarding obstetric outcomes, 9% of the patients died, 93% of births were cesarean, with 53% of premature births and 8% therapeutic abortions. 
Conclusion: The management of breast cancer during pregnancy presents a major clinical challenge, as it requires balancing effective oncological treatment with the preservation of fetal health. The review shows that advances in diagnostic and therapeutic techniques have made this situation safer for both mother and fetus. However, a highly personalized approach is still required, depending on the gestational stage and tumor characteristics. Continued research is essential to improve treatment strategies and reduce maternal mortality without compromising fetal viability.