Purpose: The objective of this study is to analyze our case series of Pregnancy associated breast cancer (PABC) and compare it with what is reported in the international literature.
Material and methods: retrospective study carried out in patients with breast cancer who are pregnant or in the postpartum period, up to one year after the delivery in the period between January 2009 up to December 2022. All patients had histologically confirmed invasive breast tumors, with immunohistochemical analysis performed by the Department of Pathology at the Hospital Alemán. Various variables were evaluated, including the mode of presentation, stage at diagnosis, treatment received, and gestational age reached.
Results: A total of 16 patients with PABC were included, representing 1.09% of all breast cancer cases at Hospital Alemán. Of these, 62.5% (n=10) during pregnancy whereas the other 37.5% (n=6) were diagnosticated in the postpartum period. The most common clinical presentation was a palpable lump, observed in 81.2% (n=13) patients. Stage II was the most frequently diagnosed, representing 68.8% (n=11) of the cases, and 37.5% (n=6) were triple negative subtypes. None of the pregnant women (10/16) terminated their pregnancy. The average gestation time was 35 weeks. Out of all patients, 9 underwent mastectomy and 6 received breast-conserving surgery. The remaining case presented with metastasis at diagnosis. Of the 10 patients diagnosed during pregnancy, 5 (50%) received neoadjuvant chemotherapy, while the remaining 5 (50%) underwent primary surgery. 
Conclusion: This retrospective study allows us to document that, despite the small number of patients evaluated, the results are comparable to those reported in the international literature. The association between breast cancer and pregnancy adds complexity to oncologic treatment planning, as many therapies may pose potential risks to the fetus. The management of this association requires a multidisciplinary approach.