title: Ethnic differences in initiation and timing of adjuvant endocrine therapy among older women with hormone receptor-positive breast cancer enrolled in Medicare Part D.
abstract: The aim of this study was to determine whether there are racial/ethnic differences in initiation and timing of adjuvant endocrine therapy (AET) after Medicare Part D drug coverage. We conducted a retrospective cohort study using data from the Surveillance, Epidemiology, and End Results-Medicare-linked data to assess ethnic, socio-demographic, and tumor characteristic variations in the initiation of AET among patients ≥65 with hormone receptor-positive breast cancer in 2007-2009 enrolled in Medicare Part D through 2010. Logistic regression models were performed to assess the association between race/ethnicity and the initiation of tamoxifen, aromatase inhibitors (AIs), and overall AET (tamoxifen or AIs) within the first 12 months of diagnosis. Of the 12,198 women with hormone receptor-positive breast cancer, 74.8 % received AET within 12 months of diagnosis, of which 17.3 % received tamoxifen and 82.8 % received AIs. After controlling for all variables, only Asian women were found to have a greater odds of initiation of overall AET compared to non-Hispanic white women (odds ratio (OR): 1.28, 95 % CI: 1.03-1.58). Hispanic Mexicans and non-Hispanic black patients had a significantly lower odds of tamoxifen initiation (0.70, 0.54-0.91; 0.25, 0.10-0.62). For AI initiation, Hispanic Mexicans and Asians had a higher odds compared to non-Hispanic white women (2.06, 1.34-3.10; 1.33, 1.11-1.61). A suboptimal proportion of women (25.2 %) did not initiate AET within 12 months of diagnosis and therefore did not receive the full benefits of treatment to reduce the risk of breast cancer recurrence and mortality. Racial/ethnic differences in the initiation of tamoxifen and AIs have important implications that require further investigation.
authors.affiliation: Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), 1200 Pressler Street, Houston, TX, 77030, USA. albert.j.farias@uth.tmc.edu.
authors.forename: Albert J
authors.identifier: http://orcid.org/0000-0002-6463-7831
authors.initials: AJ
authors.lastname: Farias
authors.affiliation: Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), 1200 Pressler Street, Houston, TX, 77030, USA.
authors.forename: Xianglin L
authors.initials: XL
authors.lastname: Du
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D047072:Aromatase Inhibitors / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000208:ethnology*; D017024:Chemotherapy, Adjuvant / Q000706:statistics & numerical data*; D005006:Ethnicity; D005260:Female; D006801:Humans; D054524:Medicare Part D; D011960:Receptors, Estrogen / Q000378:metabolism; D012189:Retrospective Studies; D018426:SEER Program; D013629:Tamoxifen / Q000627:therapeutic use; D014481:United States
chemical_list: D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D011960:Receptors, Estrogen; D013629:Tamoxifen
keywords: Adjuvant endocrine therapy; Breast cancer; Hormone receptor-positive; Initiation