Colorectal cancer is currently the third most common tumor among men and the second most common among women in Germany. "Among other things, nutritional and lifestyle habits are responsible for this," explains Michael Hoffmeister from the German Cancer Research Center (DKFZ). "But everyone can reduce their risk of colon cancer by taking care to lead a healthy lifestyle."

This is impressively demonstrated by a study of more than 4,000 bowel cancer patients and 3,000 healthy control subjects. Hoffmeister and his colleagues from the DKFZ analyzed the effects of five lifestyle factors that can be influenced: smoking or non-smoking, high or low alcohol consumption, unhealthy or healthy nutrition, little or a lot of physical activity, and overweight or normal weight.

"The more healthy lifestyle factors the participants combined, the lower was their risk of developing bowel cancer," reports Hoffmeister. Thus, for example, participants who did not smoke, adhered to a healthy diet, and were physically active, had already a lower intestine cancer risk than participants who stuck with none of the five lifestyle factors to the healthy variant. Those who cultivated a consistently healthy lifestyle had the lowest risk of colon cancer.

The five lifestyle factors proved to be of about equal importance in colorectal cancer prevention. "It played a subordinate role whether it was the non-smoking, healthy diet, or physical activity that was heeded. With all variants, the study participants reduced their risk of colorectal cancer," adds Prudence Carr, the first author of the study. The relationship between lifestyle and colorectal cancer risk was also independent of the study participants' family history. It did not matter whether they had had a colonoscopy in the past or not.

"The recommendation to live a healthy lifestyle applies to everyone, regardless of their genetic risk of colon cancer. And, of course, not only the risk of colon cancer is reduced by a healthier lifestyle. At the same time, the risk of cardiovascular diseases and many other diseases decreases," emphasizes Hoffmeister.

In further studies, the DKFZ scientists would now like to investigate to what extent the risk of colon cancer can be reduced by several preventive measures—for example through a healthier lifestyle and the performance of preventive examinations—despite a slightly increased genetic risk.

Despite major advances in prevention and early detection, colorectal cancer remains one of the most common cancers worldwide. According to estimates by the German epidemiological cancer registries and the Centre for Cancer Registry Data at the Robert Koch Institute, 33,000 men and 26,000 women in Germany will develop colorectal cancer in 2018.

The paper was published in Gastroenterology.