https://orcid.org/0000-0001-7580-540X
Abstract
Purpose
The study examined trends in breast cancer incidence, mammography testing rates, hormone-replacement therapy (HRT) use and breast cancer subtypes in a large Israeli health maintenance organization during 2000–2014.
Methods
Annual rates of mammography tests and HRTs use were analyzed in women age ≥45. Annual incidence rates of breast cancer were analyzed in women age ≥20. Estimated annual percentage changes were used to test changes in incidence rates. Invasive breast cancer subtypes were approximated by treatments received. We compared annual rates and duration of HRTs use between women diagnosed with breast cancer and those who were not, as well as HRT use between subtypes of invasive breast cancer.
Results
We identified 14,092 breast cancer cases (88% invasive, 12% in situ). The age-adjusted incidence rate of invasive breast cancer peaked in 2005, consistent with increased mammography screening that year, and decreased thereafter. HRT use decreased from 13.2% in 2002 to 4.6% in 2014. The subtypes distribution of 7771 patients diagnosed with invasive breast cancer during 2007–2014 was: luminal A and B without HER2 over-expression (HR+/HER2-), 69.7%; Luminal B with HER2 over-expression (HR+/HER2+), 8.9%; Hormone receptor-negative HER2 enriched (HR-/HER2+), 5.4%; triple negative (HR-/HER2-), 10.0%; unknown, 6.0%. Overall, in women age ≥45 diagnosed with invasive breast cancer, 76–86% did not have HRT exposure vs 14–24% who were current (within 1 year before the breast cancer diagnosis), recent (within 2–5 years), or past users (>5 years). Current/recent HRT use was statistically significantly higher in luminal vs non-luminal/unknown breast cancer subtypes (13.9% vs 8.9%, respectively; p < 0.001).
Conclusion
Our results show a decrease in breast cancer incidence that parallels the global and local decrease in HRT use. Yet, our results imply that current/recent HRT exposure may contribute to the incidence of luminal breast cancer tumors in particular. The magnitude of the effect supports findings from population-based studies.
Data Sharing Statement
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Data and Patient Privacy
The Maccabi Healthcare Services database was accessed by Maccabi’s investigators only. The confidentiality of records that could identify subjects within the database was protected, respecting the privacy and confidentiality rules in accordance with the applicable regulatory requirements. Documentation and archiving of this database was implemented. The manuscript includes aggregated data only without any identification.
Ethics Approval
The study was conducted in accordance with the ICH-GCP, Good Epidemiology Practices (GEP) and Declaration of Helsinki, Ethical Principles for Medical Research Involving Human Subjects. The study was conducted per approval of Maccabi Research Committee and the institutional review board (IRB) of Bait-Balev Medical Center.
Consent to Participate
As this is a retrospective study, the study was granted a waiver for obtaining patient consent.
Acknowledgments
The abstract of this paper was presented at the 2020 Annual Meeting of the American Society of Clinical Oncology as an online poster presentation with interim findings. The poster’s abstract was published in “Poster Abstracts” in the Journal of Clinical Oncology: https://ascopubs.org/doi/abs/10.1200/JCO.2020.38.15_suppl.e13599.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Disclosure
ABS is a medical writer contracted by Pfizer. The remaining authors declare no conflicts of interest.