Endocrine therapy initiation among Medicaid-insured breast cancer survivors with hormone receptor-positive tumors

Hormone receptor-positive (HR+) cancers account for most breast cancer diagnoses and deaths. Among survivors with HR + breast cancers, endocrine therapy (ET) reduces 5-year risk of recurrence by up to 40 %. Observational studies in Medicare- and privately-insured survivors suggest underutilization of ET. We sought to characterize ET use in a low-income Medicaid-insured population in North Carolina. Medicaid claims data were matched to state cancer registry records for survivors aging 18-64 diagnosed with stage 0-II HR + breast cancer from 2003 to 2007, eligible for ET, and enrolled in Medicaid for at least 12 of 15 months post-diagnosis. We used multivariable logistic regression to model receipt of any ET medication during 15 months post-diagnosis controlling for age, race, tumor characteristics, receipt of other treatments, comorbidity, residence, reason for Medicaid eligibility, involvement in the Breast and Cervical Cancer Control Program (BCCCP), and diagnosis year. Of 222 women meeting the inclusion criteria, only 50 % filled a prescription for ET. Involvement in the BCCCP and earlier year of diagnoses were associated with significantly higher odds of initiating guideline-recommended ET (adjusted odds ratio [AOR] for the BCCCP 3.76, 95 % confidence interval [CI] 1.67-8.48; AOR for 2004 relative to 2007 2.80, 95 % CI 1.03-7.62; AOR for 2005 relative to 2007 2.11, 95 % CI 0.92-4.85). Results suggest substantial underutilization of ET in this population. Interventions are needed to improve timely receipt of ET and to better support survivors taking ET. Low-income survivors should be counseled on the importance of ET and offered support services to promote initiation and long-term adherence.