272P Adjuvant endocrine therapy in young women with breast cancer: Impact on sexual function and quality of life

Background: Pregnancy-associated breast cancer (PABC), diagnosed during pregnancy, is rare (<1% of cases) and presents diagnostic and therapeutic challenges.Real-world data on clinical, tumor, treatment, obstetric, and neonatal outcomes are limited.Methods: We conducted a retrospective, observational study of patients diagnosed with breast cancer during pregnancy, extracted from a longitudinal cohort of 2,768 consecutive breast cancer patients followed at a single tertiary cancer center between 1994 and 2023.Data included demographics, family history, comorbidities, infertility/contraception history, gestational age at diagnosis, trimester, pregnancy management, TNM stage, molecular subtype, Ki-67, metastatic sites, treatments, and neonatal outcomes.Results: Among the 2,768 breast cancer patients followed during the study period, 25 patients (0,09%) were diagnosed with breast cancer during pregnancy.Median age at diagnosis was 35 years (range: 20-44).Family history was reported in 52%, relevant comorbidities in only 8% of patients.Prior infertility treatments were documented in 8%, and previous hormonal contraception use in 24% of patients.Breast cancer was diagnosed in the 2nd trimester in 28% and 3rd trimester in 72%; pregnancy continued in 92%.Normal birth weight was observed in 92% of newborns.Invasive ductal carcinoma was present in all but one patient.At diagnosis, 76% were cT 2 and 64% cN+.Subtypes: luminal 68%, HER2+ 20%, triple-negative 12%; median Ki-67 35%.Synchronous metastases occurred in 28% (liver, lung, bone, CNS, lymph nodes, skin), metachronous in 16%.Chemotherapy was given in 88%, including 16% during pregnancy, predominantly sequential.Targeted therapy and radiotherapy were delivered in 12% and 56%, respectively; radiotherapy was curative in 92%, and both were given post-delivery.Conclusions: PABC is rare, often advanced, and biologically aggressive.Multidisciplinary management allowed continuation of pregnancy with favorable neonatal outcomes.Systemic therapy during pregnancy and post-delivery locoregional/targeted therapies achieved curative-intent management in most cases, supporting individualized, multidisciplinary care.