Association of APOE4 genotype and treatment with cognitive outcomes in breast cancer survivors over time.

This prospective longitudinal study of breast cancer survivors (n = 167) examined the association of apolipoprotein ε4 (APOE ε4) genotype with cognition and interactions with chemotherapy or endocrine therapy up to 6 years after treatment. In general, we found no effects of ε4 across timepoints and treatment exposures; post hoc analysis at 3-6 years suggested a trend towards worse cognition in the domains of attention and learning among ε4 carriers exposed to endocrine therapy. Further study is needed.