(ChemotherapyAdvisor) – Breast cancer survivors who received chemotherapy suffer subtle but statistically significant postchemotherapy cognitive deficits, according to a new meta-analysis published in the Journal of Clinical Oncology.

“(O)n average, observed cognitive deficits in patients with breast cancer previously treated with chemotherapy are small in magnitude and limited to the domains of verbal ability and visuospatial ability,” reported Heather S.L. Jim, PhD, Health Outcomes and Behavior Program, H. Lee Moffitt Cancer Center, Tampa, Florida.

The analysis pooled data from 17 studies of a total of 807 breast cancer survivors who had received standard-dose chemotherapy 6 months or more before cognitive testing for attention, executive function, information processing, motor speed, verbal ability, verbal memory, visual memory, and visuospatial ability, Dr. Jim and coauthors reported. Studies included in the analysis included either case/control comparisons for neuropsychological tests, or longitudinal prechemotherapy and postchemotherapy cognitive test data. Control groups included breast cancer patients who had not received chemotherapy and women who did not have cancer.

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Only declines in verbal ability and visuospatial ability scores were associated with chemotherapy (P<0.01 in both cases). Patient age, education, endocrine therapy status, and time since chemotherapy did not moderate the associations. For verbal ability, study designs modulated the association with chemotherapy; chemotherapy patients performed significantly worse than noncancer controls but not significantly worse than prechemotherapy baselines or breast cancer patients who did not receive chemotherapy, the authors note.

The meta-analysis “adds to the growing body of evidence that deficits in cognitive functioning may develop after treatment of cancer with chemotherapy,” noted Gary Rodin, MD, Princess Margaret Hospital, University of Toronto, Ontario, Canada, in a companion essay.

However, the findings may not apply to other cancers, Dr. Rodin cautioned.