Cancer as a risk factor for long-term cognitive deficits and dementia

J Natl Cancer Inst. 2005 Jun 1;97(11):854-6. doi: 10.1093/jnci/dji137.


Previous studies have shown that cancer survivors frequently experience short-term cognitive deficits, but it is unknown how long these deficits last or whether they worsen over time. Using a co-twin control design, the cognitive function of 702 cancer survivors aged 65 years and older was compared with that of their cancer-free twins. Dementia rates were also compared in 486 of the twin pairs discordant for cancer. Cancer survivors overall, as well as individuals who had survived cancer for 5 or more years before cognitive testing, were more likely than their co-twins to have cognitive dysfunction (odds ratio [OR] = 2.10, 95% confidence interval [CI] = 1.36 to 3.24; P<.001; and OR = 2.71, 95% CI = 1.47 to 5.01; P<.001, respectively). Cancer survivors were also twice as likely to be diagnosed with dementia as their co-twins, but this odds ratio did not reach statistical significance (OR = 2.0, 95% CI = 0.86 to 4.67; P = .10). These results suggest that cancer patients are at increased risk for long-term cognitive dysfunction compared with individuals who have never had cancer, even after controlling for the influence of genetic factors and rearing environment.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Twin Study

MeSH terms

  • Aged
  • Cognition / drug effects
  • Cognition / radiation effects
  • Cognition Disorders / chemically induced
  • Cognition Disorders / epidemiology*
  • Cognition Disorders / etiology*
  • Dementia / chemically induced
  • Dementia / epidemiology*
  • Dementia / etiology*
  • Humans
  • Incidence
  • Medical Record Linkage
  • Neoplasms / complications*
  • Odds Ratio
  • Prevalence
  • Registries
  • Risk Assessment
  • Risk Factors
  • Sweden / epidemiology