Cognitive effects of chemotherapy in post-menopausal breast cancer patients 1 year after treatment.
OBJECTIVE
Studies in breast cancer patients indicate that chemotherapy may cause subtle cognitive disturbances in some women, but the course is unclear. The current study evaluated the cognitive effects of adjuvant chemotherapy in post-menopausal breast cancer patients 1 year following completion of treatment.


METHODS
Breast cancer patients scheduled to receive adjuvant chemotherapy (n=53) completed comprehensive neuropsychological testing before commencing chemotherapy (T1), 1 month after completing chemotherapy (T2), and again 1 year later (T3). A control group of women receiving adjuvant hormonal therapy (n=40) was tested at comparable intervals. A standardized regression-based approach was used to identify cognitive decline, and incidence of decline was compared across treatment groups.


RESULTS
Whereas at T2, chemotherapy patients were more likely to show cognitive decline than hormonal patients, by T3, the frequency of reliable cognitive decline was the same in both groups (11 and 10%, respectively). However, those chemotherapy patients receiving hormonal therapy at T3 were inferior to the chemotherapy patients not receiving hormonal treatment on composite measures of processing speed and verbal memory.


CONCLUSIONS
These data suggest that there is a subtle negative impact of chemotherapy on cognitive function in breast cancer patients shortly following completion of treatment, but that this resolves within 1 year. However, given that our control group comprises breast cancer patients receiving hormonal therapy, and indications that hormonal therapy may also adversely affect cognition, such conclusions must be considered tentative.
The Ottawa Hospital-Civic Campus, Ottawa, Ontario, Canada. bcollins@ottawahospital.on.ca
Barbara
B
Collins
Joyce
J
Mackenzie
Angela
A
Stewart
Catherine
C
Bielajew
Shailendra
S
Verma
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000188:drug therapy*; D016022:Case-Control Studies; D017024:Chemotherapy, Adjuvant; D003072:Cognition Disorders / Q000139:chemically induced*; D004359:Drug Therapy, Combination; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D005260:Female; D006801:Humans; D008875:Middle Aged; D009864:Ontario; D017698:Postmenopause; D012044:Regression Analysis