Treatment patterns, survival and economic outcomes in Medicare-enrolled, older patients with HR+/HER2− metastatic breast cancer

Abstract

Background: Endocrine therapy (ET) remains a foundation of systemic therapy for HR+/ HER2− metastatic breast cancer (MBC), although chemotherapy (CT) is used in select patients. In this “real-world” study, we explored treatment patterns, health care resource use (HCRU), costs, adverse events (AEs) and overall survival (OS) in Medicare-enrolled, older patients with HR+/HER2− MBC.

Methods: Patients with HR+/HER2− MBC (2007–2011) and aged >66 years were retrospectively analyzed using the SEER–Medicare data. Treatment patterns, HCRU, costs, AEs and OS after MBC diagnosis through end of study period (31 December 2013) were examined using descriptive and multivariable analyses.

Results: Among 3622 eligible patients, ET was the most common treatment (77%), followed by CT (50%), radiation (48%) and surgery (19%). The proportion of patients treated with ET monotherapy decreased across therapy lines, from 74% in first line (1 L) to 35% in 4 L. The total number of unique therapy regimens used was 181 in 1 L, 171 in 2 L, 128 in 3 L, and 95 in 4 L. The median OS from MBC diagnosis was 25.3 months (95% CI, 24.0–26.7). In multivariable analyses, receipt of CT and combination CT + ET (versus ET monotherapy) in 1 L, metastatic disease at initial diagnosis, larger tumor size, and presence of visceral and brain metastases at MBC diagnosis significantly predicted receipt of 2 L therapy.

Conclusions: ET was the most common first-line treatment for study patients, but its use decreased gradually in the subsequent lines. The heterogeneity in the treatment selection highlights a lack of consensus for the management of HR+/HER2− MBC in routine practice.

Keywords:

• Metastatic breast cancer
• treatment patterns
• adverse events
• health care use
• health care costs
• survival

Transparency

Author contributions: conception and design: R.K.G., G.C.C. and E.N.S.; data analysis and interpretation: all authors; manuscript writing: all authors; final approval of manuscript: all authors.

Declaration of financial/other relationships

R.K.G., S.P.N., K.L.D. and J.A.K. have disclosed that they are employees of R.T.I. Health Solutions, which received research funding from Eli Lilly and Company to perform this study. R.T.I. Health Solutions is a unit of R.T.I. International, an independent, nonprofit, research organization that does work for government agencies and private companies. G.C.C., E.N.S., G.L.P. and Y.J.H. have disclosed that they are employees of and/or shareholders in Eli Lilly and Company. L.L. was an employee of and/or shareholder in Eli Lilly and Company at the time of project execution.

Acknowledgements

The authors thanks John Forbes from RTI Health Solutions, who provided assistance with editing and developing this article in accordance with the journal’s submission guidelines.

Additional information

Funding

This study was funded in full by Eli Lilly and Company, which is conducting clinical research in advanced breast cancer. All authors representing the funding organization participated in the design of the study and interpretation of data and in writing the manuscript. The study analyses, however, were independently performed by the RTI Health Solutions’ authors as per the study protocol and analysis plan.