Can We Improve Pregnancy Rates in Hormone Receptor-Positive Breast Cancer After Endocrine Therapy? The Role of...

Background/Objectives: Young patients with hormone receptor-positive breast cancer (HR+BC) face an elevated risk of cancer-related mortality, partly due to lower adherence to hormonal therapies for fertilities concerns. This study aims to evaluate fertility preservation in patients receiving hormonal therapy (HT) alone after surgery with or without radiotherapy. Methods: This single-center prospective cohort study evaluated BC patients counseled at the Oncofertility Unit of San Raffaele Hospital (2012-2024). Results: Of 251 BC patients who received counseling, 39 met the inclusion criteria. Among 33 patients with adequate follow-up, 15 (45.5%) are still under anticancer treatment, 6 (18.2%) completed HT but do not seek pregnancy, and 12 (36.3%) sought pregnancy, of which 9 (75%) conceived. Among the nine patients who conceived, four had completed HT (one became pregnant after thawing her cryopreserved oocytes and three had a spontaneous pregnancy). Five patients who conceived had suspended HT to seek pregnancy, according to the results of the POSITIVE trial. After HT discontinuation, all patients thawed their oocytes: three had a pregnancy with a live birth, while two patients did not conceive, so one of them attempted a new in vitro fertilization cycle achieving pregnancy with a live birth, while the other one had a spontaneous pregnancy. Conclusions: Our study highlights the importance of counseling HR+ BC patients candidates for HT alone about the efficacy and safety of fertility preservation. Offering fertility preservation can mitigate the reproductive impact of therapy-related childbearing delays and potentially improve treatment adherence.