The good news is, colon cancer rates are declining slightly. The American Cancer Society provided historical data and graphs online (see References). Their estimates for 2010 include 102,900 new cases of colon cancer and 39,670 new cases of rectal cancer in the United States, along with 51,370 deaths from these sites. Men and women are at approximately equal risk.
A European study reported lifestyle changes, including weight management and physical activity, are important factors in reducing the risk. For males, achieving optimum weight offers the greatest benefit for prevention of colon cancer. For females, increased physical activity provides the greatest benefit. Thus the authors suggested a sex-specific strategy for colon cancer prevention.
A study from the University of Alabama reports African-Americans have worse outcomes, with higher death rates, than caucasians. Suggested explanations include differences in access to health care, exposure to risk factors, cancer stage at diagnosis, socioeconomic status, and tumor characteristics. The researchers performed a study of obesity and comorbidity (the presence of other diagnosed illnesses) as risk factors for mortality from colon cancer in 496 patients who underwent surgery, to see if these factors may explain the racial differences.
Surprisingly, obesity was associated with higher survival rates. Underweight patients had the highest death rates of any group classified by body mass index. Thus, obese individuals are more likely to develop colon cancer in the first place, but less likely to die from it. The authors noted that underweight patients in this study were older and had more illness from other causes. Thus, low body mass index may indicate poor health in general and less ability to recover from cancer. It is less clear why obesity is better than “optimum” weight.
For patients with stage I or II disease, comorbidity increased the risk of death from any cause. This was expected since other illnesses influence overall health.