Older Adults with Cancer Have Lower DSST Scores than Non-survivors

Results from a recent study published in the monthly journal Supportive Care in Cancer (a publication of MASCC) suggest that cancer survivors had lower Digit Symbol Substitution Test (DSST) scores than non-survivors and had more self-reported problems with memory or confusion (2016;24[5]:2155-2162).

The DSST is a neuropsychological test sensitive to brain damage, dementia, age, and depression, but the test is not sensitive to the location of brain-damage (except for damage comprising part of the visual field).

Cancer and its treatment may affect cognitive function through a number of direct and indirect pathways including inflammation, lipid metabolism, vascular damage, and changes in the blood–brain barrier. While short-term treatment-related cognitive changes are well reported, only limited research is available in older, long-term cancer survivors. 

To rectify this, Edwin VanWijngaarden, PhD, chief of the division of epidemiology and director of the doctoral program in epidemiology, and colleagues from the University of Rochester (Rochester, NY) used National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2002 to identify 408 cancer survivors and 2639 non-cancer participants aged 60 years and older. NHANES is a program of studies designed to assess the health and nutritional status of adults and children in the United States. The survey is unique in that it combines interviews and physical examinations. Cognitive function of these cancer survivors and non-cancer participants were compared using the DSST and self-reported problems with memory or confusion. 

After adjustment for covariates, cancer survivors scored, on average, 1.99 points lower on the DSST compared to non-cancer survivors (−1.99, 95% confidence interval [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).

Ultimately, researchers found that, in this nationally representative sample of older adults residing in the United States, cancer survivors had lower DSST scores than non-survivors and had more self-reported problems with memory or confusion. —Amanda Del Signore