Oncofertility in the Age of HER2 Blockade - Unanswered Questions in Breast Cancer

Sep 23, 2026

Uploaded by McQueen

Oncofertility counselling for reproductive-age patients with breast cancer has become increasingly important as survival improves. The opinion statement highlights fertility preservation, gonadotoxicity, and pregnancy safety, recommending early integration into treatment planning and prompt referral when conception is desired. Systemic therapy choice should be guided by tumour biology, with preference for regimens with lower gonadotoxic potential. Chemotherapy drives permanent ovarian insufficiency, so temporary ovarian suppression may be considered. Endocrine therapy typically does not cause irreversible damage, yet its long duration requires individualized pregnancy planning and supervised treatment interruptions in selected low-risk patients. For HER2 antibodies, chemotherapy-independent additional ovarian toxicity is not evident, while pregnancy must be avoided during therapy. For antibody–drug conjugates, PARP inhibitors, and CDK4/6 inhibitors, precautionary counselling is advised due to limited prospective human fertility data, emphasizing fertility preservation, contraception, and adherence to washout periods, alongside transparent communication and trial endpoints.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages19

Reading Time48 min

AccessFree to download

Opinion Statement

Introduction

Fertility and survivorship urgency in breast cancer

Evidence gaps in modern targeted and immune therapies

Distinct endpoints: ovarian function, fertility, pregnancy, and neonatal outcomes

Mechanisms and uncertainty in emerging therapies

Current Treatment Options in Oncology (2026) 27:30 [https://doi.org/10.1007/s1](https://doi.org/10.1007/s1) 1864-026-01396-y REVIEW Oncofertility in the Age of HER2 Blockade, Immunotherapy, PARP inhibitors, CDK4/6 inhibitors and Endocrine Treatment: Unanswered Questions in Breast Cancer Karolina Weiner-Gorzel1 · Lynda McSorley1,2 · Janice M. Walshe1,2,3 Received: 2 March 2026 / Accepted: 19 May 2026 © The Author(s) 2026 Opinion Statement As survival among reproductive-age patients with breast cancer continues to improve with modern therapies, concerns regarding fertility preservation, gonadotoxicity, and pregnancy safety have become increasingly prominent. Fertility considerations are well-recognized contributors to treatment refusal and premature discontinuation, therefore, oncofertility counselling should be initiated at diagnosis and integrated into therapeutic planning. Prompt referral for fertility preservation is essential for patients who may wish to conceive, without compromising oncologic outcomes. Systemic therapy selection should remain driven by tumour biology and recurrence risk; however, when clinically equivalent regimens are available, those with lower gonadotoxic potential are preferred. Cytotoxic chemotherapy is the main determinant of permanent ovarian insufficiency, and temporary ovarian suppression during chemotherapy should be routinely considered in appropriate candidates. Endocrine therapy is not associated with irreversible ovarian damage, but its long duration necessitates individualized planning for pregnancy, including supervised treatment interruption in selected low-risk patients. HER2-monoclonal antibodies should be delivered according to standard indications, as it does not appear to confer substantial additional ovarian toxicity beyond chemotherapy; however, pregnancy must be avoided during treatment. For antibody–drug conjugates, PARP inhibitors, and CDK 4 and 6 inhibitors, the absence of prospective human fertility data supports a precautionary approach, including pre-treatment fertility preservation, effective contraception during therapy, and adherence to recommended washout periods. Given the substantial gaps in clinical evidence, transparent communication of uncertainty is essential. The integration of standardized reproductive endpoints into clinical trials, alongside the development of predictive tools is critical to support evidence-based counselling and optimize long-term survivorship outcomes. Keywords Oncofertility · Breast cancer · Fertility outcomes · Ovarian function · Pregnancy outcomes · Novel breast cancer agents · Targeted breast cancer treatment 􀀍 Karolina Weiner-Gorzel [kwgorzel@gmail.com](kwgorzel@gmail.com) 1 Department of Medical Oncology, St Vincent’s University Hospital, Dublin, Ireland 2 Department of Medical Oncology, St Vincent’s Private Hospital, Dublin, Ireland 3 School of Medicine, University College Dublin, Dublin, Ireland Introduction Breast cancer (BC) is the most common malignancy in women under 40 years of age, accounting for nearly one in five new cancer diagnoses in the United States [1] . As survival continues to improve with advances in systemic therapy [2, 3], attention has increasingly shifted toward survivorship issues—particularly fertility preservation, ovarian function, and pregnancy safety [4, 5] . This issue is becoming increasingly urgent. As childbearing is increasingly delayed worldwide, a growing proportion of women are diagnosed with BC before completing reproductive plans. Fertility concerns are therefore not only a survivorship issue but also a documented factor contributing to treatment refusal or premature discontinuation [6]. Accordingly, leading oncology societies and experts in the field—includingthe European Society for Medical Oncology (ESMO) and the American Society of Clinical Oncology (ASCO) recommend that fertility-related discussions be integrated into routine care for all reproductive-age patients

FAQs

When should oncofertility counselling and fertility preservation be initiated for patients with breast cancer?

Counselling should be initiated at diagnosis and integrated into therapeutic planning. Prompt referral for fertility preservation is essential for patients who may wish to conceive.

How do different systemic therapies relate to gonadotoxicity and ovarian damage?

Cytotoxic chemotherapy is the main determinant of permanent ovarian insufficiency, so temporary ovarian suppression during chemotherapy may be considered. Endocrine therapy is not associated with irreversible ovarian damage, while HER2 monoclonal antibodies do not appear to add substantial ovarian toxicity beyond chemotherapy; however, pregnancy must be avoided during treatment.

Why is a precautionary approach recommended for antibody–drug conjugates, PARP inhibitors, and CDK4/6 inhibitors?

The absence of prospective human fertility data supports precautionary counselling, including pre-treatment fertility preservation, effective contraception during therapy, and adherence to recommended washout periods.

Sep 23, 2026

Uploaded by McQueen