Is tamoxifen good enough for the Asian population in ER+ HER2-post-menopausal women with early breast cancer? - A nationwide population-based cohort study

Q: What is the study’s main objective regarding tamoxifen and aromatase inhibitors?

To determine whether recurrence rates differ between tamoxifen and aromatase inhibitors in ER-positive, HER2-negative post-menopausal women with early breast cancer using real-world data.

Q: How was the cohort constructed and what data sources were used?

The study used Taiwan’s National Health Insurance claims data and the Taiwan Cancer Registry, identifying 6,050 patients aged over 55 diagnosed between 2012 and 2016.

Q: What were the main findings on recurrence risk between the two endocrine therapies?

Tamoxifen was associated with a lower recurrence risk than aromatase inhibitors (adjusted HR 0.32, p < 0.0001). Stage 2 showed a pronounced reduction, while no statistical difference was found in stage 1.

Sep 21, 2026

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Real-world evidence is used to assess whether tamoxifen provides sufficient benefit for Asian women with early breast cancer who are ER-positive and HER2-negative after menopause. A retrospective nationwide cohort analyzes Taiwan’s NHI claims data and the Taiwan Cancer Registry, including 6,050 patients diagnosed between 2012 and 2016, with recurrence follow-up through 2020. Recurrence-free survival is compared using Kaplan–Meier methods and multivariable hazard models accounting for age, stage, adjuvant therapy, endocrine choice, and adherence. Tamoxifen is linked to a lower adjusted recurrence risk versus aromatase inhibitors (HR 0.32), with notable effects in stage 2 and higher recurrence risk related to stage 2, grade 3, and non-adherence.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages13

Reading Time33 min

AccessFree to download

Abstract

Background

Methods

Results

Conclusion

Introduction

PLOS ONE OPEN ACCESS Citation: Chang C-H, Lee Y-C, Huang C-W, Lu Y-M (2024) Is tamoxifen good enough for the Asian population in ER+ HER2-post-menopausal women with early breast cancer? A nationwide populationbased cohort study. PLoS ONE 19(11): e0313120 . [https://doi.org/10.1371/journal.pone.0313120](https://doi.org/10.1371/journal.pone.0313120) [Editor:](Editor: Pirkko L. H)[ Pirkko L. H](Editor: Pirkko L. H)a¨rko¨nen, Turun Yliopisto, FINLAND Received: August 11, 2023 Accepted: October 19, 2024 Published: November 27, 2024 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: [https://doi.org/10.1371/journal.pone.0313120](https://doi.org/10.1371/journal.pone.0313120) [Copyright:](Copyright:) © [2024 Chang](2024 Chang) et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The data that support the findings of this study are available from Taiwan’s Ministry of Health and Welfare’s Health and Welfare Data Center (HWDC) . However, due to RESEARCH ARTICLE Is tamoxifen good enough for the Asian population in ER+ HER2-post-menopausal women with early breast cancer? A nationwide population-based cohort study Chuan-Hsun Chang1☯, Yi-Chan Lee2☯, Chun-Wen Huang3, You-Min Lu4 * 1 Department of Surgery, Cheng Hsin General Hospital, Taipei, Taiwan, R.O.C, 2 Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan, R.O.C, 3 Office of the Superintendent, Cheng Hsin General Hospital, Taipei, Taiwan, R.O.C, 4 Division of Clinical Pharmacy, Department of Pharmacy, Cheng Hsin General Hospital, Taipei, Taiwan, R.O.C ☯ These authors contributed equally to this work. * [ch1306@chgh.org.tw](ch1306@chgh.org.tw) Abstract Background Numerous clinical trials have compared the efficacy of endocrine therapy in post-menopausal breast cancer patients. This study aims to explore whether there is a difference in recurrence rates between this population using tamoxifen and aromatase inhibitors (AIs) by analyzing real-world data. Methods This retrospective cohort study utilized the National Health Insurance (NHI) claims data and the Taiwan Cancer Registry (TCR) . We identified 6,050 patients aged over 55 diagnosed with ER-positive, HER2-negative early breast cancer between 2012 and 2016 (4,451 on AIs alone and 1,599 on tamoxifen alone) . Recurrence in both groups was assessed until the end of 2020. Hazards were measured based on age of diagnosis, cancer stage, adjuvant chemotherapy, radiation therapy, type of endocrine therapy used, and adherence. Recurrence-free survival between the AIs and tamoxifen groups was evaluated using the KaplanMeier model. Results The average age was 65.1 years, with a median follow-up time of 5.7 years and a median duration of endocrine therapy of 4.5 years. The recurrence rate was 2.2% . Using tamoxifen as endocrine therapy reduces the risk of recurrence compared to AIs (adjusted HR: 0.32, p < 0.0001) . There was no statistical difference between the two drugs in stage 1 breast cancer. However, in stage 2, the risk of breast cancer recurrence decreased to 0.15 times with the use of tamoxifen compared to AIs (p = 0.0002) . Stage 2 cancer, histological grade 3, and non-adherence increased recurrence risk in post-menopausal breast cancer patients. PLOS ONE | [https://doi.org/10.1371/journal.pone.0313120](https://doi.org/10.1371/journal.pone.0313120) November 27, 2024 1 / 13 licensing restrictions, these data are not publicly accessible. Data access is restricted to individuals who register

FAQs

What is the study’s main objective regarding tamoxifen and aromatase inhibitors?

To determine whether recurrence rates differ between tamoxifen and aromatase inhibitors in ER-positive, HER2-negative post-menopausal women with early breast cancer using real-world data.

How was the cohort constructed and what data sources were used?

The study used Taiwan’s National Health Insurance claims data and the Taiwan Cancer Registry, identifying 6,050 patients aged over 55 diagnosed between 2012 and 2016.

What were the main findings on recurrence risk between the two endocrine therapies?

Tamoxifen was associated with a lower recurrence risk than aromatase inhibitors (adjusted HR 0.32, p < 0.0001). Stage 2 showed a pronounced reduction, while no statistical difference was found in stage 1.

Sep 21, 2026

Upload by Evangeline