Can the same American Institute for Cancer Research (AICR) healthy lifestyle recommendations that lower the risk of many cancers also help colorectal cancer survivors live longer? A new paper suggests they can, finding that survivors who most followed AICR’s Cancer Prevention Recommendations after their diagnosis were at lower risk of dying compared to those who least followed the Recommendations.
Physical activity appeared to play a key role in survival.
The paper was published in Cancer Epidemiology, Biomarkers & Prevention and was conducted independently of AICR. It adds to a growing body of research suggesting that lifestyle can contribute to a healthier life after a cancer diagnosis.
Emerging research on lifestyle and survivorship
AICR’s latest Cancer Prevention Recommendations, released in 2018, focus on how diet, nutrition, physical activity and body weight link to many of the most common cancers. The
Recommendations are based on an analysis of the global research that includes 51 million people and 3.5 million cancer cases. However, there is far less research related to how these same lifestyle practices connect with improving the well being of cancer survivors.
Cancer survivors in general face the added risk of recurrence along with a higher risk of developing a secondary cancer. Treatments can also place many at increased risk of cardiovascular disease. AICR recommends that cancer survivors aim to follow the
Recommendations given to the general population for prevention, when and if they are able.
Previous research by independent scientists has found that following AICR’s recommendations improve several outcomes for survivorship. There is also research that suggests adhering to AICR’s Recommendations can help people live longer.
Higher scores link to longer survival
This latest study included 1,491 men and women who were participants of two larger studies: the Nurses’ Health Study and the Health Professionals Follow-up Study. All the participants were healthy when they entered one of the studies decades earlier. They regularly filled out questionnaires about their diet, exercise and other lifestyle habits, along with other relevant physical and medical issues. At some point between 1986 and 2010, some of the participants in these studies were diagnosed with colorectal cancer.
The authors scored the participants’ responses based on how much each person followed AICR’s Cancer Prevention Recommendations for diet, physical activity and body weight. Eating plenty of fruits, vegetables and whole grains while limiting sugary beverages were among the components making up the diet scores. Being both active and avoiding sedentary activity—measured by TV time—contributed to the activity score.
After a median of 8 years, 641 of the participants had died with 179 of those from colorectal cancer. Survivors who scored as most following AICR’s Recommendations after a diagnosis had a 37 percent lower risk of dying from any cause when compared with those who least followed the Recommendations. Survival was improved the most among colorectal cancer survivors who adhered more closely to the Recommendations both before and after diagnosis.
Physical activity and increased survival
When the authors eliminated BMI—a measure of body fatness—from their analysis due to the potential for disease-related weight loss, the links between lifestyle and survival emerged even stronger. The group most adhering to AICR’s Diet and Activity Recommendations after their diagnosis had half the risk of dying from colorectal cancer and a 41 percent lower risk of dying overall during the study compared to the survivors who least followed the Recommendations.
And consistently following the Recommendations both before and after diagnosis linked to lower risk of dying from both colorectal cancer and any cause.
People’s dietary habits after their cancer diagnosis did not appear to have an effect on mortality. The findings point to physical activity as being a potential driver for increased survival, the authors write.
Participants in the highest scoring group of the post-diagnostic lifestyle score reported, on average, over three times higher post-diagnostic physical activity compared to those in the lowest scoring group when scored with BMI, says study author Stephanie Smith-Warner, PhD, of the Harvard T.H. Chan School of Public Health. That is roughly equivalent to walking briskly 7 hours every week versus 2.1 hours. For the post-diagnostic lifestyle score without BMI, physical activity amounts roughly equated to 7.6 hours of brisk walking per week among the group with the highest lifestyle score versus 1.6 hours among those with the lowest score.
“This large variation in post-diagnostic physical activity level may have contributed largely to the difference in survival we observed with increasing adherence to the WCRF/AICR Cancer Prevention Recommendations in our study,” says Smith-Warner.
This study was a relatively large one but it has several limitations, including the use of self-reported data, and the study could not control for treatment. Also, many participants were excluded from the analysis because they were missing post-diagnostic lifestyle data. These participants had shorter survival times, were older and had more advanced tumors, making these findings more applicable to those with good prognosis at the time of diagnosis, the authors write.
More research is needed to better understand how diet and lifestyle factors affect colorectal cancer survival. As more people are surviving and living longer after a cancer diagnosis, the research promises to expand. And the importance of general good health applies to cancer survivors as well. The same AICR Cancer Prevention Recommendations that focus on a healthy lifestyle can also lower risk of heart disease and other chronic conditions.
For survivors who can and are ready to move toward a healthier lifestyle, join AICR’s Healthy10 Challenge, a free interactive 10-week program.
The study was funded by the National Cancer Institute.
This article was originally published by the American Institute for Cancer Research on August 17. It is republished by permission.