By Dr Ananya Mandal, MD
There are several ways to prevent or at least reduce the risk of colorectal cancer. Although the exact cause of the cancer is unknown, certain lifestyle measures seem to reduce the possibility of the cancer. Some of the preventive measures include:
There are several studies that show that diet that is low in saturated fats and high in fibre diets reduce the risk of colorectal cancers. High fibre diets include those with at least five portions of fresh fruit and vegetables a day and whole grains. These also reduce the risk of other cancers and heart disease. Diet should also be low in red and processed meats to reduce the risk of colorectal cancers. Those who take more than 90 grams (cooked weight) of red and processed meat a day are advised to reduce it to less than 70gms per day.
Regular physical activity and exercise reduces the risk of developing colorectal cancers. It is recommended adults exercise for at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity (i.e. cycling or fast walking) every week.
Maintenance of healthy weight
Being overweight and obese increases the risk of colorectal cancer. Maintenance of healthy body weight helps in reduction of risks of colorectal cancer.
People who smoke are at a higher risk of colorectal cancer. They need to quit to reduce the risk of colorectal cancers.
Screening and monitoring
Screening for colorectal cancers is not a preventive measure that can stop the cancer but can help detect the cancer at early stages. This makes chances of success with treatment of the cancer better.
Most colorectal cancer arise from adenomatous polyps. These can be detected and removed during colonoscopy. There are several studies that show that colonoscopy would decrease by > 80% the risk of cancer death, provided it is started by the age of 50, and repeated every 5 or 10 years.
Guidelines under National Comprehensive Cancer Network suggests that good options for screening average risk individuals with negative family history of colon cancer and personal history negative for adenomas or Inflammatory Bowel diseases include:
Colonoscopy every 10 years (currently deemed Gold-Standard of care)
Flexible sigmoidoscopy every 5 years along with
Fecal occult blood testing annually or
Double contrast barium enema
Prevention with drugs
There are several phytochemicals, and other food components like calcium or folic acid (a B vitamin), and NSAIDs like aspirin that are known to reduce the risk of colorectal cancers. It is advised that Aspirin should not be taken routinely to prevent colorectal cancer because it can increase the risk of bleeding and kidney failure.
A clinical practice guideline of the U.S. Preventive Services Task Force (USPSTF) recommended against taking aspirin (grade D recommendation). The meta-analysis by the Cochrane Collaboration of randomized controlled trials published through 2002 showed that there is insufficient evidence that calcium supplementation prevents colorectal adenomatous polyps. An earlier study from National Cancer Institute also found that vitamin D was beneficial in preventing colorectal cancer.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)