title: A metaanalysis of studies of the effects of cancer chemotherapy on various domains of cognitive function.
abstract: BACKGROUND
  Little is known about the effects of chemotherapy on cognitive function. The purposes of this metaanalysis were to estimate the effect sizes for the effect of chemotherapy on each domain of cognitive function and to differentiate effect sizes by each method of comparison of effects (i.e., normative data, control group, or baseline data).
  
  
  METHODS
  Sixteen studies that evaluated cognitive function in chemotherapy patients were included in the study. DSTAT metaanalysis software was used to calculate an effect size and confidence intervals for each neuropsychologic test. Tests were assigned to a specific cognitive domain, and an average effect size was determined for each domain.
  
  
  RESULTS
  Only one domain of cognitive function (i.e., visual memory) had significant chemotherapy-induced impairment across all comparison types. However, when the neuropsychologic test scores of chemotherapy patients were compared with normative data, significant effect sizes were found for four domains of cognitive function (i.e., executive function, information processing speed, verbal memory, visual memory). In addition, significant, albeit small, effect sizes were found for language and verbal memory when chemotherapy patients' test scores were compared with test scores of healthy matched controls. All significant averaged effect sizes were in the negative direction, indicating that mean scores on neuropsychologic tests for patients who had received chemotherapy were on average lower than comparison scores.
  
  
  CONCLUSIONS
  Data from this metaanalysis supported the hypothesis that chemotherapy can have a negative impact on cognitive function. However, most deficits in this study ranged from small to moderate and were nonsignificant.
authors.affiliation: Patient Care Services, Kaiser Permanente Medical Center, San Francisco, California 94115, USA. Catherine.Jansen@kp.org
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Jansen
authors.forename: Christine
authors.initials: C
authors.lastname: Miaskowski
authors.forename: Marylin
authors.initials: M
authors.lastname: Dodd
authors.forename: Glenna
authors.initials: G
authors.lastname: Dowling
authors.forename: Joel
authors.initials: J
authors.lastname: Kramer
mesh_terms: D000328:Adult; D003071:Cognition / Q000187:drug effects*; D006801:Humans; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy*; D009483:Neuropsychological Tests