Cognitive function and discontinuation of adjuvant hormonal therapy in older breast cancer survivors: CALGB 369901 (Alliance).

Abstract

To investigate the effects of cognitive function on discontinuation of hormonal therapy in breast cancer survivors ages 65+ ("older"). Older breast cancer survivors with invasive, non-metastatic disease, and no reported cognitive difficulties were recruited from 78 Alliance sites between 2004 and 2011. Eligible survivors (n=1280) completed baseline interviews; follow-up was conducted annually for up to 7years. Survivors with estrogen-receptor-positive (ER+) cancers who initiated hormonal therapy (n=990) were included. Self-reported cognitive function was measured using the EORTC-QLQ30 scale; a difference of eight points on the 0-100 scale was considered clinically significant. Based on varying rates of discontinuation over time, discontinuation was evaluated separately for three time periods: early (<1year); midpoint (1-3years); and late discontinuation (>3-5years). Cox models for each time period were used to evaluate the effects of cognition immediately preceding discontinuation, controlling for age, chemotherapy, and other covariates. Survivors were 65-91years old (mean 72.6years), and 79% had stages 1 or 2A disease. Overall, 43% discontinued hormonal therapy before 5years. Survivors who reported lower cognitive function in the period before discontinuation had greater hazards of discontinuing therapy at the treatment midpoint (HR 1.22 per 8-point difference, CI 1.09-1.40, p<0.001), considering covariates, but cognition was not related to discontinuation in the other periods. Self-reported cognitive problems were a significant risk factor for discontinuation of hormonal therapy 1-3years post-initiation. Additional research is needed on the temporality of cognitive effects and hormonal therapy to support survivorship care needs of older survivors.