First-line endocrine therapy for advanced breast cancer. A real-world study at a Latin American university health institution

Abstract

Objective: Clinical guidelines recommend the use of endocrine therapy (ET) in advanced hormone receptor positive (HR+) human epidermal growth factor receptor type 2 negative (HER2-) breast cancer (BC) patients in the absence of visceral disease or ET resistance. Furthermore, studies indicate similar response and survival rates using ET or cytotoxic chemotherapy (CT).

Methods: Herein, we assessed clinical characteristics, type of systemic therapy and survival rates of advanced HR + HER2-BC patients in our database.

Results: A total of 172 advanced HR + HER2-BC patients were treated at our institution between 1997 and 2019. Sixty percent received first-line ET (4% received combined ET). Median age of this subset was 55 years (range: 30–86). Similarly, the median age of patients that received CT was 54 years (range: 21–83). Over time, 30% of patients received ET in the 2000–2005 period; this increased to 70% in the 2016–2019 period (p = .045). Overall survival (OS) was 97 months and 51 months for patients treated with ET or CT, respectively (p = .002).

Conclusions: To the best of our knowledge this is the first study assessing the use of ET in Chilean advanced HR + HER2-BC patients. Several patients in our institution receive CT without indication. The increase in ET usage over time can be attributed to better and faster immunohistochemical detection methods for Estrogen Receptor (ER), changes in educational and government policies, and a wider variety of ET options. Finally, clinical trials have failed to demonstrate a substantial benefit of CT over ET in this setting.

Keywords:

• Hormonal antineoplastics
• breast neoplasm
• endocrine breast disease
• chemotherapy

Transparency

Declaration of funding

No sponsorship/funding.

Declaration of financial/other relationships

The authors have no financial or other relationships to be declared. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

BW, FA, LM, MLB, TM, MC, FD, MPP and CS were involved in the conception and design of the manuscript, participated in the collection and interpretation of data. SM, HG, BN, CI, JM, JP, EK and MG made substantial contributions to the first draft and critically revised the final version of the manuscript. All authors read and approved the final version of the manuscript to be published and are accountable for all aspects of this work.

Acknowledgements

No assistance in the preparation of this article is to be declared.