Dec 15, 2014
By Shira Klapper, Senior Writer/Editor
“Turn off the TV and go outside and play” is an admonishment heard by many children—sage advice that seems to benefit adults as well. According to a new article in the Journal of Clinical Oncology (JCO), the simple recipe of “more exercise, less TV” might be particularly beneficial for survivors of colorectal cancer (CRC).
The study, “Pre- and Post-Diagnosis Physical Activity, Television Viewing, and Mortality Among Colorectal Cancer Patients in the NIH-AARP Diet and Health Study,” published online, ahead of print, December 8, 2014, asked how time devoted to exercising and watching TV— both before and after diagnosis— affected the risk of dying among survivors of colorectal cancer. To answer this question, the researchers used data from the NIH-AARP Diet and Health Study, which provided pre-diagnosis information on 3,797 survivors of CRC and post-diagnosis information on 1,759 survivors.
In summing up the findings of the study, first author Hannah Arem, PhD, MHS, of the National Cancer Institute, said, “The takeaway message from our study is that the colorectal cancer survivors who both watched less TV and did more exercise had the lowest mortality compared to those who watched more TV and did less exercise.”
More exercise associated with lower mortality risk
The study found that survivors of CRC who exercised seven hours or more per week before their diagnosis had a 20% lower risk of dying of any cause compared to survivors who did not exercise at all. Those who exercised seven hours or more per week after their diagnosis had a 31% lower risk of dying of any cause compared to survivors who did not exercise—a similar benefit was observed among survivors who exercised as little as four hours per week both before and after diagnosis. Exercising after diagnosis was associated with a reduced risk of death independent of whether or not the survivor exercised before diagnosis. On average, survivors’ reports on exercise were given four years after diagnosis.
Four to five hours of TV watching per day associated with greater mortality risk
The study also reported that survivors of CRC who watched more than five hours of TV per day before their diagnosis had a 22% increased risk of dying of any cause, compared to survivors who watched less than two hours per day. As far as TV watching after diagnosis, survivors who watched more than four hours of TV per day had a 25% increased mortality risk compared to survivors who watched less than two hours per day; however, this post-diagnosis difference was not statistically significant.
Colorectal Cancer Survivorship: an important public health issue
Only one previous study examined the association between sedentary activity and survivorship among survivors of CRC, and this current study is the first to look specifically at TV watching. Dr. Arem said that one of the reasons the researchers chose to focus on TV watching is that it is a behavior that can be modified with relative ease.
“TV watching is the most prevalent leisure time behavior, and it is an area where individuals can intervene,” said Dr. Arem. “It’s a lot harder to ask someone to change how they sit at work or which transportation mode they use. Asking people to reduce time in front of a TV is a public health message that can be put into action.”
According to Dr. Arem, identifying behaviors that can reduce the mortality risk among survivors of CRC is an important public health issue since the population of survivors numbers one million in the United States, and is growing.
“This is a population that deserves to have more research on their specific needs,” said Dr. Arem.
And as this new research in JCO suggests, one of those specific needs may be to leave the couch and take a walk outside.
“The findings in this study add another piece of evidence that for the more than one million survivors of colorectal cancer, even moderate exercise, such as walking four hours per week and keeping TV watching to two hours a day, might improve survival in this population.”
Hannah Arem, PhD, MHS, is a Post-doctoral Fellow in the Nutritional Epidemiology Branch of the Division of Cancer Epidemiology and Genetics at the National Cancer Institute. She has been an ASCO member since 2012.
Read the abstract of the original JCO article.
View the PDF of the original JCO article.
Arem H, Pfeiffer RM, Engels EA. Pre- and post-diagnosis physical activity, television viewing, and mortality among colorectal cancer patients in the NIH-AARP Diet and Health Study. J Clin Oncol. Epub 2014 Dec 8.
The Exclusive Coverage series on ASCO.org highlights selected research from JCO and JOP with additional perspective provided by the lead or corresponding author.
@ 2014 American Society of Clinical Oncology