Anti-HER2 treatment in everyday practice - how we treat older women with breast cancer differently

Q: Why did the study focus on anti-HER2 use in women over 75?

Because patients older than 75 are often excluded from anti-HER2 clinical trials, and it remains unclear how extensively these therapies are delivered in routine care.

Q: How was anti-HER2 therapy use measured in the study?

The researchers used a nationwide registry-based cohort, describing treatment patterns with descriptive statistics and estimating the direct effect of age using Poisson regression.

Q: What did the results show about anti-HER2 treatment across age groups?

Anti-HER2 therapy use was high under 75 (83–95%), decreased at ages 75–79 (about 60%), and declined further with increasing age to around 8% at age 90 and above.

Sep 30, 2026

Uploaded by Hazel

Examining real-world care in Norway for HER2-positive breast cancer, this study evaluates how chronological age affects the use of targeted anti-HER2 therapies. Patients older than 75 are frequently underrepresented in clinical trials, leaving uncertainty about routine-treatment decisions in older populations. Using a nationwide registry-based cohort of women diagnosed with stage I-III disease (2012–2021), the analysis quantifies age-related patterns and estimates age’s direct association with therapy receipt.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Abstract

Purpose

Methods

Results

Conclusions

Introduction

Rationale for studying age effects

Current treatment landscape

Methods

Registry-based cohort and analytic approach

Breast Cancer Research and Treatment (2026) 215:54 [https://doi.org/10.1007/s10549-025-07888-z](https://doi.org/10.1007/s10549-025-07888-z) Anti‑HER2 treatment in everyday practice: how we treat older women with breast cancer differently S. Hjorth1,2 · K. F. Vandraas1,2,3 · C. B. Trewin‑Nybråten4 · E. Botteri1,5 · G. Ursin6,7,8 · B. K. Andreassen1 · N. C. Støer1,2 Received: 3 November 2025 / Accepted: 24 December 2025 / Published online: 7 January 2026 © The Author(s) 2026 Abstract Purpose Targeted therapies have improved survival in human epidermal growth factor receptor 2 positive breast cancer (HER2 + BC) . However, patients over 75 years of age are often excluded from clinical trials of anti-HER2 therapies, and it is unclear to what extent they receive these treatments in routine care. To address this, we examined age-related patterns of anti-HER2 therapy use in real-world clinical practice in Norway. Methods In a nationwide registry-based cohort, we identified women diagnosed with stage I-III HER2 + BC during 2012– 2021. We investigated treatment patterns using descriptive statistics and estimated the direct effect of age on anti-HER2 therapy use by Poisson regression. Results Among 3526 women with HER2 + BC, anti-HER2 therapy use was consistently high (83–95%) in those under 75 years, decreased to 60% at ages 75–79, and declined further with advancing age to 8% at ≥ 90 years. Neoadjuvant antiHER2 therapy also decreased with age (from 24% in patients under 75 to 12% in patients over 75 years) . Accounting for cancer characteristics, comorbidities, polypharmacy, and socio-economic factors, older patients had reduced likelihood of receiving any anti-HER2 therapy compared with patients younger than 55 (RR 0.75, 95% CI 0.66–0.85, p < 0.001, at age 75–84 and RR 0.21, 95% CI 0.11–0.41, p < 0.001, at age 85 +) . Conclusions Anti-HER2 therapy use declined substantially after the age of 75 even when accounting for comorbidities and polypharmacy. Chronological age appears important in planning treatment for patients with HER2 + BC. Specific guidelines pertaining to older patients with HER2 + BC are needed to avoid potential undertreatment. Keywords HER2-positive · Breast cancer · Older patients · Anti-HER2 targeted therapies Introduction Older patients, especially those over 75 years, are under-represented in pivotal clinical trials leading to cancer therapy approval and implementation in clinical practice [1] . This * N. C. Støer [nast@fhi.no](nast@fhi.no) 1 Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway 2 Norwegian Research Center for Women’s Health, Department of Obstetrics and Gynecology, Oslo University Hospital, Oslo, Norway 3 Department of Oncology, Oslo University Hospital, Oslo, Norway 4 Department of Registration, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway represents a challenge for clinicians when planning treatment for older patients. Historically, patient’s age has had a decisive impact on treatment guidelines. During later years, consensus statements recommend comprehensive geriatric assessment (CGA) of patient frailty before treatment 5 Section for Colorectal Cancer Screening, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway 6 Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway 7 Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway 8 Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA initiation, not relying solely on age [2] . Yet studies indicate that less than half of breast cancer (BC) patients over 70 years receive a CGA prior to treatment initiation [3–5] . Approximately 15% of BC patients present with HER2 + disease (HER2 + BC), a prognostic trait that guides adjuvant treatment planning [6]. At present, adjuvant therapy for HER2 + BC routinely includes one year of t

FAQs

Why did the study focus on anti-HER2 use in women over 75?

Because patients older than 75 are often excluded from anti-HER2 clinical trials, and it remains unclear how extensively these therapies are delivered in routine care.

How was anti-HER2 therapy use measured in the study?

The researchers used a nationwide registry-based cohort, describing treatment patterns with descriptive statistics and estimating the direct effect of age using Poisson regression.

What did the results show about anti-HER2 treatment across age groups?

Anti-HER2 therapy use was high under 75 (83–95%), decreased at ages 75–79 (about 60%), and declined further with increasing age to around 8% at age 90 and above.

Sep 30, 2026

Uploaded by Hazel