Abstract P5-11-16: Cognitive Effects of Endocrine Therapy in Patients with Breast Cancer
Authors: Berndt U , Thomssen C , Lantzsch T , Leplow B. 
Published: April 2011

Background: Adjuvant endocrine therapy is the mainstay in the therapy of primary breast cancer. However, the impact of endocrine therapy on cognitive function in patients with breast cancer is still unclear. Numerous studies suggest a protective effect of estrogens on neurons. From these findings it has been derived that the almost complete estrogen deprivation by aromatase suppression would modify cognitive performances. The primary aim of our study was to ascertain, whether neurocognitive functioning is altered in breast cancer patients receiving various endocrine therapies.

Patients and Methods: In a cross sectional study we investigated 80 post-menopausal women with breast cancer. Memory, spatial cognition, processing speed and attention were evaluated. Patients who ever received chemotherapy were not included. To compare cognitive task performance we constituted four treatment groups (see tab. 1).

Tab. 1 Groups and Medication

Patient characteristics were equally distributed, however, “switch” patients had received significantly more hormone replacement therapy before the onset of breast cancer than all other groups. We also evaluated mood, depression, anxiety, pre-morbid intelligence and self-perception of memory in order to receive homogenous groups. All participants were interviewed about their compliance to their medication. In this study, we used univariate statistical analyses of variance (ANOVA) and we calculated the effect-sizes of significant values. In case of lacking normal distribution we applied non-parametric statistics.

Results: Women who solely received aromatase inhibitor treatment showed a significant impairment of general memory (p=0.01, d=1.15) and verbal memory (p=0.026, d=0.97) in comparison to the control group. In more than 50% of the aromatase inhibitor patients we found below-average performance concerning verbal memory compared to normative data. The aromatase inhibitor group performed significantly worse than the tamoxifen-(p=0.035, d=0.64) and the “switch-group” (p=0.03, d=0.91) with regard to attention. With respect to their spatial abilities, no significant differences in navigation and in mental rotation were noted. With regard to path integration we solely ascertained significant lower results of the aromatase inhibitor patients compared with the tamoxifen group (p=0.04). Overall, no differences were observed between the “switch”- and the tamoxifen patients. Surprisingly, most patients perceived their own memory performance as averaged. Self-perception of memory correlated with anxiety and depression but not with test scores.

Conclusion: Treatment with tamoxifen alone seems to be less harmful for cognitive abilities than treatment with aromatase inhibitors alone. Patient may benefit from prior tamoxifen therapy when sequentially treated with aromatase inhibitors however this observation must be confirmed in further studies as well as the potential role of prior hormone replacement therapy and the objective adherence to therapy assessed by serum drug levels measurements.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-11-16.