Among patients with a history of cancer, risk of Alzheimer disease (AD) might be lower: a study published in JAMA Network Open showed that elderly cancer patients had modestly higher memory function and slower memory decline both before and after their diagnosis compared with similarly aged individuals who remained cancer free. This result suggests that the risk of cancer may be lower among patients with AD, and that cancer survivors may have a lower risk of developing AD than people who did not develop any tumour.
The inverse association between cancer and AD or other neurodegenerative diseases has been already described extensively in the literature, however evidence remains scarce on the long-term cognitive trajectories, as Monica Ospina-Romero, MD, from the department of epidemiology and biostatistics at University of California, San Francisco, and colleagues wrote.
To compare long-term memory trajectories before and after cancer with those memory trajectories of individuals cancer free, researchers conducted a population-based cohort study which included over 14.500 U.S. adults from the Health and Retirement Study. Biennially, they assessed participants from 1998 to 2014 to determine composite memory score and compare the rates of memory change. Of 14,583 participants included in the study, followed for 11.5 in average, 2,250 had a cancer diagnosis while 12,333 had not. The rate of memory decline in the decade before a cancer diagnosis was 10.5% which was slower than memory decline in similarly aged cancer-free individuals. In addition, a new cancer diagnosis was associated with a short-term decrease in memory compared with memory before the diagnosis.
Analysis revealed moreover that average memory function immediately before cancer diagnosis was slightly higher for individuals diagnosed at age 75 years than memory function among cancer-free adults of the same age. The results also showed a slower rate of memory decline after a cancer diagnosis compared with individuals without cancer.
“These findings support the possibility of a common pathologic process working in opposite directions in cancer and AD,” the researchers wrote. “Identification of a potential association between carcinogenesis and neurodegeneration may open a new avenue in research for prevention and treatment of AD.”
Photo credits: Ignacio Palomo Duarte, creative commons licence 2.0