More exercise and less television were both associated with decreased all-cause mortality among older patients with colorectal cancer in a large, prospective cohort study, according to a report published online Dec. 8 in the Journal of Clinical Oncology.
Survivors of the disease have shown high a prevalence of sedentariness and TV viewing in previous research, so these findings “present an opportunity for clinicians to encourage behavioral changes to positively impact longevity,” said Hannah Arem, Ph.D., of the National Cancer Institute, Bethesda, Md., and her associates.
They assessed the relationships among both prediagnosis and postdiagnosis activity levels on the one hand and all-cause mortality and disease-specific mortality on the other using data from the National Institutes of Health–American Association of Retired Persons (NIH-AARP) Diet and Health Study. The original cohort included 566,398 men and women aged 50-71 years at baseline in 1995. These participants, who resided in six U.S. states and two metropolitan areas, completed mailed questionnaires regarding moderate to intense physical activities they performed, such as fast walking, running/jogging, biking, playing tennis, dancing, swimming, playing golf, and performing aerobics or heavy gardening.
For their study, Dr. Arem and her associates identified 3,784 of these participants who completed the survey a mean of 5 years before their diagnosis of colorectal cancer and 1,759 who did so a mean of 4.2 years after their diagnosis.
The investigators found that before a colorectal cancer diagnosis, increased activity (more than 7 hours per week) was associated with a 20% lower risk of all-cause mortality, compared with no such activity. After a colorectal cancer diagnosis, increased activity was associated with a 31% lower risk of all-cause mortality and a 47% lower risk of disease-specific mortality.
In contrast, watching more than 4 hours per day of TV, as opposed to watching 0-2 hours per day, was associated with a 20% increase in all-cause mortality both before and after a colorectal cancer diagnosis (J. Clin. Oncol. 2014 Dec. 8 [doi:10.1200/JCO.2014.58.1355]).
When the data were combined in a joint-effects analysis, patients who had the highest activity levels (more than 7 hours per week) and the lowest TV viewing levels (2 or fewer hours per day) showed the lowest all-cause mortality risk of all.
In addition, “our results suggest that physical activity was not as protective among those who performed high levels of [activity] but also watched 3 or more hours of TV per day, suggesting that encouraging both more exercise and less TV in this survivor population may lead to improved longevity outcomes,” Dr. Arem and her associates noted.
These associations were not influenced by the patient’s sex, exact disease site, body mass index, tumor stage or grade, type of surgery, or general health status, they added.