Association of Endocrine Therapy Initiation Timeliness With Adherence and Continuation in Low-Income Women With Breast Cancer

Abstract

IMPORTANCEThough adjuvant endocrine therapy (AET) has proven efficacy in treating hormone receptor-positive (HR-positive) breast cancer, patient adherence to AET and continuation of treatment as recommended by guidelines remain suboptimal, especially for low-income patients. OBJECTIVE To quantify timelines for initiating AET and assess their association with short-and longterm adherence and continuation of AET in low-income women with breast cancer. DESIGN, SETTING, AND PARTICIPANTS This population-based retrospective cohort study included women younger than 65 years diagnosed with first primary HR-positive breast cancer between January 1, 2007, and December 31, 2013, followed up for 5 years after the first use of AET through December 2018, and identified from the linked Missouri Cancer Registry and Medicaid claims data set. EXPOSURES Time to initiation (TTI) as days from the date of last treatment (surgery, radiotherapy, or chemotherapy) to the first date of AET prescription fill. MAIN OUTCOMES AND MEASURESThe main outcomes were adherence to AET as medication possession ratio of 80% or greater and continuation of AET as no gap in medication supply for at least 90 days. Odds ratios (ORs) of adherence and continuation over 1 to 5 years were estimated using logistic regression adjusted for demographic, clinical, and neighborhood variables. Analyses were performed between September 1, 2020, and May 31, 2022. RESULTS Among 1711 patients, median TTI was 53 (IQR, 26-117) days. A total of 1029 patients (60.1%) were aged 50 to 64 years old, 1270 (74.2%) were non-Hispanic White, and 1133 (66.2%) were unmarried. In the first year after initiation, 1317 (77.0%) were adherent and 1015 (59.3%) continued AET. Over the full 5 years, 376 (22.0%) were adherent and 409 (23.9%) continued AET.Longer TTI was significantly associated with poorer adherence at every year, with an OR of 0.97 (95% CI, 0.95-0.99) for 1-year adherence and an OR of 0.94 (95% CI, 0.90-0.97) for 5-year adherence per 1-month increase in TTI. Longer TTI was also associated with lower odds of short-term, but not longterm, continuation (OR, 0.97 [95% CI, 0.95-0.99] for 1-year continuation and 0.98 [95% CI, 0.96-0.99] for 2-year continuation). CONCLUSIONS AND RELEVANCEIn this cohort study, longer time to AET initiation was associated with lower odds of short-term and long-term adherence to AET in Medicaid-insured patients with breast cancer. Therefore, early interventions targeting treatment initiation timelines may positively impact adherence throughout the course of treatment and, therefore, outcomes.

Factors influencing the first and the fifth years adherence to adjuvant endocrine therapy in breast cancer patients in a low income country

“…[4,9,19] It's well established that low-income populations are at greater risk of having difficulty in maintaining the treatment according to its prescription. In the US, for instance, the proportion of patients adherent to AET at the first year of treatment was over 80% for Medicare-insured women, which contrasts with 55-60% for Medicaid-insured women [20]; for those unfamiliar with the program's differences, the latter covers extremely low-income families, with fragile social support. Our population is mostly represented by women without medical insurance other than the public healthcare service and these patients were assessed in a period of financial insecurity aggravated by the COVID pandemic; hence, we believe that this impoverishment could be a part of the equation leading to low adherence.…”

American Cancer Society’s report on the status of cancer disparities in the United States, 2023

“…89 Longer time to initiation may also be associated with poorer adherence to cancer treatment. 90 The high cost of treatment for many cancer types 91,92 and increases in private health insurance plans' cost sharing 93,94 can make treatments less affordable to individuals with limited incomes or no or suboptimal insurance, and many individuals with cancer experience challenges in paying for their treatments. 95,96 This financial hardship or financial toxicity results in higher prevalence of financial distress, asset depletion, medical debt, and bankruptcy, especially among people of color and of lower SES, [95][96][97][98] and has been Ever cigarette smoking was defined as smoking at least 100 cigarettes in a lifetime.…”

“…For example, in a study of >557,000 women aged 65 years and older diagnosed with stage 0–III breast cancer from 2010 to 2017, Black, Hispanic, AIAN, and Asian women were about twice as likely to experience a delay in breast cancer treatment initiation (>90 days after diagnosis) compared with White women 89 . Longer time to initiation may also be associated with poorer adherence to cancer treatment 90 …”

Identifying the predictors of adherence to oral endocrine therapy in racial/ethnic minority patients with low socioeconomic status

“…In HR + BC patients, better adherence to oral endocrine therapy (OET) results in superior outcomes [4][5][6][7][8][9]. Despite a 30-50% reduction in recurrence risk by 5-10 years of OET, nonadherence rate is high among the patients [10][11][12]. The Food and Drug Administration (FDA)approved OETs used are tamoxifen and Aromatase Inhibitors (AIs) such as anastrozole, exemestane, and letrozole [13][14][15][16][17][18].…”