In addition to reducing the risk of developing colorectal cancer, regular physical activity and maintenance of a healthy body weight may improve survival among individuals diagnosed with colorectal cancer. These results were published in the journal Gut.
In 2005, the American Cancer Society estimates that there will be 145,000 new colorectal cancer diagnoses in the U.S. and 56,000 colorectal cancer deaths. In both men and women, colorectal cancer is the third most commonly diagnosed cancer. It follows lung and prostate cancer for men and lung and breast cancer for women. Colorectal cancer develops in the large intestine, which includes the colon (the longest part of the large intestine) and the rectum (the last several inches).
Physical inactivity and obesity are known to increase the risk of developing colorectal cancer, but there is little information about whether these factors also influence survival with colorectal cancer.
To explore the link between body size and physical activity and survival with colorectal cancer, researchers in Australia analyzed data from the Melbourne Collaborative Cohort Study. Between 1990 and 1994, this study enrolled 41,528 study subjects. The current analysis includes the 526 subjects who were diagnosed with colorectal cancer between the time of study enrollment and 2002. Information about body size and physical activity was collected at the time of study enrollment (before cancer diagnosis).
During a median of 5.5 years of follow-up, 208 deaths occurred among the 526 subjects with colorectal cancer. Eighty-seven percent of these deaths were due to colorectal cancer.
- After accounting for age, sex, and cancer stage, subjects who exercised had a 27% reduction in risk of death from colorectal cancer.
- The benefit of exercise was especially apparent for subjects with stage II or III cancer: In this group, subjects who exercised had a 51% reduction in risk of death from colorectal cancer.
- Risk of death from colorectal cancer increased with increasing body fat and increasing waist circumference.
The researchers conclude that a greater amount of fat in the waist and lack of regular physical activity before a colorectal cancer diagnosis result in worse colorectal cancer survival.
Reference: Haydon AMM, MacInnis RJ, English DR et al. Effect of Physical Activity and Body Size on Survival After Diagnosis With Colorectal Cancer. Gut. 2006;55:62-67.