(National) December 28, 2006 - Colon cancer is the third most common cancer in the country. Slightly more men than women get it.
But a new study shows men who exercise, even moderately, can make a difference in preventing colon cancer.
59-year-old John Knudson used to be too busy to exercise until a routine colonoscopy showed small growths, called polyps, on his colon.
"The concern was cancer, the polyps themselves weren't a problem, but you know I was aware of the potential of getting cancer from it," said Knudson.
After 40, men are at higher risk for colon cancer. Polyps increase that risk because they can become malignant. But so, too, can normal cells that divide too quickly in the folds of the colon.
"If there too many proliferating cells, too many abnormally growing cells, can eventually become a polyp that can eventually become a cancer. So you want to stop that process early before it even becomes a polyp and certainly before it becomes a cancer," says Epidemiologist Dr. Anne McTiernan.
McTiernan, of Fred Hutchinson cancer research center, studied 102 healthy men. All were at higher risk for colon cancer. Half the participants, including John, worked out six days a week, one hour a day, for a year. The other half remained sedentary. Biopsies of colon tissue before and after the study showed exercise was beneficial.
"It was sort of more dramatic than I thought it might be," said Knudson.
Men who didn't exercise continued to show proliferating cells. The active men significantly reduced the number of fast-growing cells.
"We found four hours a week was really the cut-off, which is a little more than half an hour to 45 minutes a day of exercise," said McTiernan.
John continues running and being screened. He's run one marathon and plans on more.
Men in this study had a family history of colon cancer or a previous diagnosis of polyps. If you have these risk factors, experts suggest you get screened early and carefully.
It is recommended you get your first colonoscopy ten years before the age your family member got their colon cancer.