HNPCC is the most common type of hereditary colorectal cancer, and results from inherited mutations in genes involved in DNA mismatch
FAP results from inherited mutations in the adenomatous polyposis coli (APC) gene. People with FAP tend to develop numerous colorectal
polyps, and polyps may occur as early as the preteen years.
All people with a family history of colorectal cancer should discuss their history with their physician in order to identify the optimal approach to surveillance and prevention. Screening may need to begin at a very early age for some people.
Inflammatory Bowel Disease (IBD): The two major types of inflammatory bowel disease—ulcerative colitis and Crohn’s disease—substantially increase the risk of colorectal cancer. An estimated 10-15% of deaths among people with IBD are due to colorectal cancer.
Diet: Many aspects of diet have been studied in relation to colorectal cancer, often with mixed results. Dietary factors that have been reported to increase the risk of colorectal cancer include red meat and alcohol.
Obesity: Obesity has consistently been linked with an increased risk of colon cancer in men.
Smoking: Studies of the link between tobacco and risk of colorectal cancer have been inconsistent. A pooled analysis of the Women’s Health Initiative studies found an increased risk of rectal cancer among smokers, but no increased risk of colon cancer.7,8 Some previous studies, however, have reported a link between smoking and colon cancer.
We may not be able to completely eliminate our risk of developing colorectal cancer, but there are steps that we can take to reduce our risk.
Diet: Eating a diet rich in fruits, vegetables, and whole grains may reduce the risk of colorectal cancer in addition to providing other health benefits. Since red meat and alcohol may increase the risk of colorectal cancer, these should be consumed in moderation (if at all). Finally, since obesity may increase the risk of colorectal cancer, it’s important to eat a diet that allows you to achieve or maintain a health body weight.
Exercise: Studies suggest that regular physical activity reduces the risk of colon cancer. Developed for the general population (and not specifically for cancer survivors), the guidelines recommend that adults engage in at least 30 minutes of moderate-to-vigorous physical activity on five or more days per week. A longer duration of exercise (45 to 60 minutes) may provide additional benefits. Moderate-intensity activity includes brisk walking and cycling on level terrain. Vigorous activity includes cycling or walking up hills and jogging.
Detection and Treatment of Precancerous Polyps: In the case of colorectal cancer, however, screening can sometimes prevent the development of cancer by identifying precancerous polyps. Removing these polyps can prevent the later development of cancer. Colorectal cancer screening tests are described in more detail below.
Nonsteroidal Anti-inflammatory Drugs (NSAIDS): NSAIDS are used to reduce inflammation and pain; they include drugs such as aspirin and ibuprofen. Studies have suggested that NSAIDS reduce the risk of colorectal cancer.
Calcium/Vitamin D: Calcium may provide a modest colorectal cancer benefit. One study showed that patients taking 1200 mg of calcium daily demonstrated a 20% reduction in colorectal adenoma formation and a 45% reduction in advanced adenoma formation.
Preventive surgery: Preventive surgery may be recommended for some people at very high risk of colorectal cancer, such as those with FAP. Surgery is performed to remove the colon (and sometimes the rectum and other organs as well) before cancer develops.