Deaths from Colon Cancer Can Be Reduced
Colon cancer ranks as the second most common cause of cancer-related deaths in the US, but lifestyle changes and early interventions can significantly reduce the mortality rate, say HSPH researchers.
"Given what we know about risk factors and prevention methods, colon cancer should not be a major cause of death in the US," said Edward Giovannucci, assistant professor in the Department of Nutrition.
Risk
factors for colon cancer have been well established, he said. Approximately
five percent of colon cancer patients possess a genetic predisposition
to the disease, but the overwhelming majority of risk factors stem from
other sources.
Diet plays a key role in colon cancer prevention, and recent findings may surprise consumers who have been taught that high-fiber diets decrease risks of colon cancer incidence. In the 1960s, researchers first described a correlation between fiber and colon cancer after observing groups in Africa who ate a lot of fiber and presented low incidence rates of colon cancer. The researchers suggested that the correlation may be attributed to the fact that fiber moves stool more quickly out of the bowel. Intuitively, the theory made sense, said Giovannucci, but experts didn't conduct prospective epidemiological studies until the last 10 years.
Folate intake may prove much more important than fiber in reducing colon cancer risk, he said. Giovannucci and fellow HSPH and HMS researchers reported in the October 1, 1998 issue of Annals of Internal Medicine that the folic acid in multivitamins might substantially reduce the risk for colon cancer if taken over several years.
If tumors in the colon form, aspirin seems to arrest their growth rate, said Giovannucci. Cells produce compounds called prostaglandins that promote cell division in the colon. Aspirin may inhibit prostaglandins so that the cell division slows or stops, but to achieve the effect, people most likely would have to start taking the aspirin at age 40 and not stop.
Giovannucci said that a steady diet of aspirin can cause unpleasant and dangerous side effects in some people such as bleeding in the stomach. "Is it worth taking aspirin every day to achieve the same benefit as one or two colonoscopies?" he asked. "Maybe. Some people may prefer aspirin over a colonoscopy." He added that the hypothesis is not proven, but animal studies offer compelling support.
March is National Colorectal Cancer Awareness Month.
