P4-12-02: The Association of Anastrozole Adherence and Cognitive Function in Breast Cancer.
Authors: Sereika SM , Dunbar-Jacob JM , Ryan CM , Adam B , Bender CM 
Published: June 2012

Background: Women with breast cancer experience deterioration in cognitive function with adjuvant therapy. Little is known about whether declines in cognitive function are associated with nonadherence to oral hormonal therapy over time. We investigated anastrozole adherence over time and its association with cognitive function over the first 12 months of therapy in women with breast cancer.

Methods: Using a prospective cohort design, 169 women with early stage breast cancer were monitored for 12 months 1) continuously for their adherence to anastrozole using electronic event monitoring and 2) objectively for cognitive function via a neuropsychological battery every 6 months for the first 12 months of hormonal therapy. Adherence data were summarized monthly as to the number of doses taken as the percentage of prescribed doses taken and the timing of doses taken as the percentage of days with correct intake and the percentage of doses with correct timing. Six cognitive factors, derived via exploratory factor analysis applied to the neuropsychological battery, were used for analysis. Data were analyzed using descriptive and longitudinal methods.

Results: Participants were white (n=166, 98.2%), well-educated (Mean=15.1 years; SD=2.9, range=10-26) and on average 61.1 years of age (SD=5.9, range=46-75). Most had stage 1 breast cancer (n=123, 72.8%) and were prescribed anastrozole either alone (n=110, 65.1%) or immediately after chemotherapy (n=59, 34.9%). Initial levels of adherence were fairly high based on number of (Mean=89.1, SD=27.1, range=0-111.1) and timing of doses taken (Days with correct intake: Mean=86.4, SD=26.8, range=0-100; Doses with correct timing: Mean=83.6, SD=29.8, range=0-100); however, adherence decreased over the first 12 months of therapy (p&lt;.05) in terms of the number of and timing of doses taken and regardless of chemotherapy use. Specifically, we found a linear decrease for the percentage of prescribed doses taken (linear: t=-2.97, p=.0035); however, nonlinear declines were observed for both the percentage of days with correct intake (linear: t=-3.33, p=.0011; quadratic: t=2.10, p=.0371) and the percentage of doses taken at the correct time (linear: t=-3.38, p=.0009; quadratic: t=2.28, p=.0242), suggesting a slowing of the rate of decline in adherence related timing of doses for months 9 through 12. We found that a decrease in executive functioning was related to lower percentages of prescribed doses taken (p=.06) and doses taken at the correct time (p=.06) from pretreatment to 6 months post-anastrozole initiation and even greater evidence (p&lt;.05) from pretreatment to 12 months post-anastrozole initiation. From 7 to 12 months post-anastrozole initiation, we found that a decrease in visual learning and memory was related to lower percentages of prescribed doses taken (p=.04), days with correct intake (p=.04), and doses taken at the correct time (p=.03), while a decrease in attention was related to a lower percentage of days with correct intake (p=.04).

Conclusions: These results suggest that breast cancer survivors who experience deterioration in cognitive function tend to have lower adherence. Efforts should be made to develop interventions to compensate for declines in cognitive function and to improve anastrozole adherence.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-12-02.