Keeping a healthy lifestyle — by refraining from smoking, limiting alcohol intake, eating healthily, working out and maintaining a small waistline — can go a long way in preventing colorectal cancer, according to a new study.
Nearly a quarter of colorectal cancer cases could be prevented by adhering to these five lifestyle recommendations, said study researcher Dr. Anne Tjonneland, of the Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen.
"Bowel cancer is probably one of the cancers where lifestyle habits have the highest impact on risk," Tjonneland told MyHealthNewsDaily.
In the United States, the National Cancer Institute anticipates 51,370 deaths from colon and rectal cancers in 2010. Together, these cancers were second only to lung and bronchial cancer in the number of U.S. deaths from 2003 through 2007.
According to the Danish study, the risk of colorectal cancer can be lowered by being physically active for more than 30 minutes every day, having no more than seven drinks for a woman or 14 drinks for a man every week, not smoking, having a waistline smaller than 35 inches (88 centimeters) for women and 40 inches (102 cm) for men, and maintaining a healthy diet.
Even modest differences in lifestyle habits can have a substantial impact on colorectal cancer risk, Tjonneland said.
The study was published online today (Oct. 26) in the British Medical Journal.
Following the rules
The researchers surveyed 55,489 men and women between the ages of 50 and 64 over the course of nearly 10 years to learn about their lifestyle habits. By 2006, at the end of the 10-year period, 678 people had been diagnosed with colorectal cancer.
Researchers then compared how closely those with colorectal cancer and those without had adhered to the five lifestyle recommendations.
They found that if participants had adhered to all five lifestyle recommendations, 23 percent of the colorectal cancer cases could have been avoided. If all participants had followed just one of the recommendations, 13 percent of the colorectal cancer cases could have been avoided, the study said.
"What should be done as a next step would be to actually make people change their habits in an intervention study," Tjonneland told MyHealthNewsDaily.
The message isn't necessarily new, but the study itself is important because it looked at how lifestyle factors can act together to affect colorectal cancer risk, instead of looking at each factor on its own, said Dr. Jeffrey Meyerhardt, a colorectal cancer specialist at Dana-Farber Cancer Institute in Boston.
"It's been well-known that avoidance of obesity, increasing physical activity, certain dietary things, lack of smoking, reduction of alcohol are all things that can relatively reduce one's risk of developing cancer, but most papers individually look at each of these things," said Meyerhardt, who was not involved with the study.
Research published in 2000 in the journal Cancer Causes & Control found similar results. Harvard School of Public Health researchers found, in a study of 47,927 men ages 40 to 75, that those who adhered to a similar set of lifestyle recommendations had a lower colon cancer risk than those who didn't. And a 2009 study published in the journal Colorectal Disease found a correlation between body mass index and colorectal cancer risk.
Explaining the events
The reasons why following the recommendations can help prevent colorectal cancer are not certain, but it is known that high insulin and diabetes are risk factors for the disease, Meyerhardt said.
"Obesity and lack of activity leads to high insulin states, which can lead to growth of cancer cells," Meyerhardt said.
An American Cancer Society official noted, however, that the new study doesn't address whether lifestyle changes have more or less of an impact on people with a higher risk of developing colorectal cancer than on the average person.
The biggest risk factor for colorectal cancer is a family history of the disease, or a family or personal history of colon polyps, which are small clumps of cells that can turn cancerous, said , said Dr. Durado Brooks, director of Prostate and Colorectal Cancers at the society, who was not associated with the study.
"Regardless of lifestyle — you can do everything right — and you can still have significant chance" of developing colorectal cancer, Brooks said. "Getting screened for all adults starting at age 50, or earlier if they have risk factors, is the single most important thing that people can do."