# Can We Improve Pregnancy Rates in Hormone Receptor-Positive Breast Cancer After Endocrine Therapy? The Role of Fertility Preservation Beyond Gonadotoxic Therapy

## TL;DR

This study explores fertility preservation in hormone receptor-positive breast cancer patients treated with hormonal therapy alone, showing that it can help improve pregnancy rates and treatment adherence.

## Contribution

The study is the first to assess fertility preservation in hormone receptor-positive breast cancer patients not undergoing gonadotoxic therapies.

## Key findings

- 36.3% of patients who sought pregnancy after fertility preservation successfully conceived.
- Fertility preservation was effective even after discontinuation of hormonal therapy, with some achieving live births.
- Counseling on fertility preservation improved treatment adherence in hormone receptor-positive breast cancer patients.

## Abstract

Fertility preservation is safe and effective in breast cancer patients; however, there is a lack of data regarding fertility preservation in hormone receptor-positive breast cancer patients treated exclusively with hormonal therapy. This study aims to assess the feasibility and reproductive outcomes of fertility preservation in this group of patients often excluded from standard oncofertility pathways. We want to emphasize the importance of considering fertility preservation not only to mitigate the gonadotoxic effects of chemotherapy but also to counteract age-related fertility decline during prolonged endocrine therapy. This study may encourage the use of fertility-sparing treatments in patients who are not referred for gonadotoxic therapies, promoting patient adherence to treatment.

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.