Persistent cognitive changes in breast cancer patients 1 year following completion of chemotherapy.

Numerous studies have shown that there are acute cognitive side-effects of chemotherapy for breast cancer. Presumably, patients are more concerned about chronic treatment effects. This report from a prospective longitudinal study compares cognitive functioning in 56 breast cancer patients 1 year after chemotherapy to that of 56 healthy individuals. Neuropsychological test scores were combined into verbal memory, visual memory, working memory, and processing speed scores, as well as an overall summary score, and analyzed using multi-level growth modeling. Frequency of cognitive decline was assessed using regression-based change scores. There was significant rebound in the overall summary score from end of treatment to 1-year follow-up as well as a substantial reduction in the frequency of cognitive decline. However, more than one-third of the breast cancer patients who showed cognitive decline immediately following completion of chemotherapy showed persistent cognitive decline 1 year later. Furthermore, recovery was not seen in all cognitive domains. In fact, the rebound was significant only for working memory. Longer multi-site studies are recommended to explore the risk factors for and the permanence of these longer-term cognitive effects.