Cognitive impairment following chemotherapy for breast cancer: The impact of practice effect on results.

Chemotherapy-Related Cognitive Impairment (CRCI) can be an adverse effect in women treated for breast cancer. Some longitudinal studies reported deficits in attention, memory, and executive function following treatment, but other studies did not find cognitive changes. It is known that practice effects (PE) on repeated assessments with cognitive tests contribute to the discrepancies in these results, but its influence on scores has not been systematically explored. The present study examines the impact of PE on retest scores in a group of women with breast cancer treated with chemotherapy and evaluated longitudinally. METHOD: 51 women with breast cancer treated with a combination of 5-fluorouracil, epirubicin, and cyclophosphamide with or without taxanes were assessed after surgery but before chemotherapy (T1), post-chemotherapy (T2), and at one year after T2 (T3). Longitudinal changes on cognitive performance were analyzed twice: when retest scores were not corrected for PE and when correction for PE was applied to T2 and T3 scores. RESULTS: When PE was not corrected, progressive improvement over time in measures of memory and divided attention at T2 and T3 was observed. In contrast, when PE was corrected, worsening was found in measures of memory, fluency, executive function, and attention at T2 and in attention and executive function at T3. Results after correction for PE are in line with previous longitudinal studies that report cognitive impairment after treatment with chemotherapy for breast cancer. CONCLUSION: Accounting for PE is recommended to identify true change on cognition through treatment with chemotherapy for breast cancer.

Role of taxanes in chemotherapy-related cognitive impairment: A prospective longitudinal study.

PURPOSE: The aim of this study is to elucidate the role of taxanes on cognition when they are administered as a part of the treatment with a fluorouracil, epirubicin and cyclophosphamide (FEC) regimen for breast cancer (BC). METHODS: Two groups of women (n = 51) with a novel diagnostic of BC that were treated with a combination of FEC alone (6 cycles of FEC) or with taxanes (4 cycles of FEC plus 8 cycles of taxanes) were compared at three moments: before chemotherapy, after its completion (short-term evaluation) and at a mean of 74.5 weeks from baseline as a long-term evaluation. RESULTS: Both groups showed worsening in tests of attention and executive functions on the short-term assessment, with the group treated with taxanes showing more number of affected cognitive measures at this time point, including verbal learning and speed measures. At the long-term evaluation, cognitive dysfunction was still found in attention and executive functions in both groups. CONCLUSION: Our results suggest that chemotherapy for BC with a FEC regimen can have a negative effect on cognition. Acute deficits seem to be larger when taxanes are added, but treatment seems to affect cognition also at long term.