Chemotherapy patients have long complained of the mental fog that tends to accompany treatment, but a new study suggests that certain combinations of chemo drugs may have long-term effects on cognition.
Researchers looked at 196 women who had been treated for early-stage breast cancer with a three-drug chemotherapy regimen. The women underwent cognition testing an average of 21 years after they had received chemo. They were compared with 1,509 healthy women who had never had cancer. The women in the study ranged in age from 50 to 80.
The women who had chemotherapy fared much worse than the control group on tests of verbal memory, cognitive processing speed, executive function and psychomotor speed.
Previous studies suggested that "chemo brain" can persist for five years after treatment, but this study is the first to show possible permanent cognitive damage. The study is important because the number of long-term survivors of chemotherapy is increasing.
The chemo regimen used by the women in the study -- a combination of cyclophosphamide, methotrexate and fluorouracil nicknamed CMF -- was commonly used between 1976 and 1995. It is no longer used for early-stage breast cancer. However, cyclophosphamide and fluorouracil are still used. "Even if the findings of our study were specific to CMF, they would remain relevant," the authors wrote.
More research is needed, they said, to understand how chemotherapy affects the brain. The study was published Monday in the Journal of Clinical Oncology.