The Effect of Lifestyle on Large Bowel (Colon and Rectal) Cancer

According to 2015 data, large bowel (colorectal) cancer is the third most common cancer type among both men and women in our country and the second most common cause of cancer death.

The most frequently mentioned risk factors for colorectal cancer development are age, family history, inflammatory bowel diseases and genetic syndromes. Research in recent years has shown that lifestyle factors such as low consumption of fiber-rich foods, vegetables and fruit, a high-fat diet, low physical activity and obesity also pose risks for colon cancer. Alcohol and tobacco use have likewise been associated with colorectal cancers. Almost everyone has now heard this information, so what should be done next?

How Should Physicians Counsel on Lifestyle Factors and Nutrition in Relation to Colorectal Cancer?

Current research seeks to establish how physical activity in patients diagnosed with and recovered from colon cancer affects disease outcomes, and ongoing studies investigate this further. Studies suggest dietary patterns such as a Western diet and high carbohydrate consumption increase recurrence risk after treatment and recovery. Some studies also show that aspirin and COX-2 inhibitors reduce colorectal cancer recurrence risk.

Certain lifestyle factors play a role in colorectal cancer outcomes. For example, a body mass index above 35 kg/m2 has been observed to increase recurrence risk and the risk of another primary cancer in colon cancer patients.

Similarly, increased recurrence and mortality risk has been associated with a Western diet involving high consumption of processed foods, fat and red meat.

A study of people with stage III colon cancer who had received treatment and recovered showed that exercising 6 hours or more weekly reduced recurrence risk and extended survival.

Experts speaking with patients noted that changing lifestyle can be difficult and that nutrition specialists, physiotherapists, exercise instructors and healthy living specialists can help. An important point to consider is that nutrition and lifestyle can help reduce the risk of other health problems in people recovering after colon cancer treatment.

For example, a cancer and nutrition study in Europe involving more than 500 000 participants showed that doubling consumption of fiber-rich foods could reduce colorectal cancer risk by 40%. Developed countries are observed to have higher consumption of red meat subjected to cooking or preservation processes.

Research has shown that red meat and processed meat products increase colorectal cancer risk. Based on the data, experts recommend limiting their consumption for colorectal cancer prevention.

In addition, 52 studies investigating the relationship between colorectal cancer risk and physical activity show a link between insufficient exercise and cancer. This mechanism accompanying exercise is related to reductions in fat tissue and body mass index, lower inflammation and insulin levels, and increased insulin sensitivity. Experts therefore recommend 75 minutes of vigorous or 150 minutes of moderate exercise weekly. They also recommend limiting sedentary behavior (such as time in front of television and computers).

To examine the effect of weight on colorectal cancer risk, research involving more than 7 million participants across 56 studies was conducted. Experts observed that each 5 kg/m2 increase in body mass index increased colorectal cancer risk by 18% . This association was seen more in colon than rectal cancer, particularly in men.

Nutrition and lifestyle are cultural rather than primarily medical matters. Physicians can and should, of course, make recommendations. People should learn and support healthy living. Worldwide, however, people supporting healthy lifestyles appear to choose them because of cultural norms rather than consulting their physicians. Educating our physicians on this topic is therefore important. This may allow us to contribute more effectively to the effort.