Frailty and Adherence to Adjuvant Hormonal Therapy in Older Women With Breast Cancer: CALGB Protocol 369901

Abstract

Purpose Most patients with breast cancer age ≥ 65 years (ie, older patients) are eligible for adjuvant hormonal therapy, but use is not universal. We examined the influence of frailty on hormonal therapy noninitiation and discontinuation. Patients and Methods A prospective cohort of 1,288 older women diagnosed with invasive, nonmetastatic breast cancer recruited from 78 sites from 2004 to 2011 were included (1,062 had estrogen receptor–positive tumors). Interviews were conducted at baseline, 6 months, and annually for up to 7 years to collect sociodemographic, health care, and psychosocial data. Hormonal initiation was defined from records and discontinuation from self-report. Baseline frailty was measured using a previously validated 35-item scale and grouped as prefrail or frail versus robust. Logistic regression and proportional hazards models were used to assess factors associated with noninitiation and discontinuation, respectively. Results Most women (76.4%) were robust. Noninitiation of hormonal therapy was low (14%), but in prefrail or frail (v robust) women the odds of noninitiation were 1.63 times as high (95% CI, 1.11 to 2.40; P = .013) after covariate adjustment. Nonwhites (v whites) had higher odds of noninitiation (odds ratio, 1.71; 95% CI, 1.04 to 2.80; P = .033) after covariate adjustment. Among initiators, the 5-year continuation probability was 48.5%. After adjustment, the risk of discontinuation was higher with increasing age (P = .005) and lower for stage ≥ IIB (v stage I) disease (P = .003). Conclusion Frailty is associated with noninitiation of hormonal therapy, but it does not seem to be a major predictor of early discontinuation in older patients.