Cognitive function in cancer survivors: Analysis of the 1999-2002 National Health and Nutrition Examination Survey.

Abstract

193 Background: Cancer and its treatment may affect cognitive function in up to 35% of survivors months after treatment. While short-term treatment-related cognitive changes are well recognized, only limited research is available in older, long-term survivors of cancer. Methods: Using NHANES data from 1999 through 2002, 408 cancer survivors and 2,639 non-cancer participants age 60 and above were identified. Cognitive function of these groups were compared on self-reported problems with memory or confusion and using the Digit Symbol Substitution Test (DSST), a test of processing speed, attention, and learning and working memory involving executive functions domains. Results: Cancer survivors were on average 72.8 years old and 11.5 years from diagnosis. After adjustment for covariates, cancer survivors scored, on average, 1.99 points lower on the DSST compared to non-cancer survivors (ß=-1.99, 95%CI -3.94, -0.05). Cancer survivors also had 17% higher odds of self-reporting problems with memory or confusion (OR 1.17, 95%CI 0.89, 1.53). Similar results were observed among survivors ≥ 5 years from diagnosis (ß =-2.38, 95%CI -4.57, -0.18, OR1.41, 95%CI 0.99, 2.02). Results suggest that age modifies the association between cancer diagnosis and DSST score (p=0.11) with a larger effect size in the younger group (between 60 and 75 years). Among those younger than 75, cancer survivors performed 3.25 points lower on the DSST compared to non-cancer survivors (ß =-3.25; 95%CI -5.88, -0.62). However, this difference was only 0.18 points lower among those 75 or older (ß =-0.18; 95%CI -2.94, 2.57). Conclusions: This is the only study to examine domain specific cognitive deficits in a large, nationally representative, older population of long-term cancer survivors and the first to report deficits in processing speed, attention, and learning and working memory domains. These domains are thought to be important for social and executive functioning and quality of life. Characterizing affected domains and subpopulations will help to develop and test effective interventions and may influence treatment practices in older cancer patients.