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What populations are susceptible to this disease?

Researchers have identified several risk factors that increase a person’s chance of developing colorectal cancer. A family history of colorectal cancer: Relatives of colorectal cancer patients are also at increased risk for developing this disease. Some of these families may have a colorectal cancer syndrome such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC). Colorectal cancer may also seem to run in some families that do not have one of these syndromes. Accurate identification of people with these syndromes is important because their doctors will recommend specific measures to prevent cancer or find it as early as possible, when treatment is most successful. Some doctors recommend that all people with colorectal cancer have an evaluation of their family history of the disease.

Familial colorectal cancer syndromes: The following conditions make it more likely that a family member could develop cancer. Familial adenomatous polyposis (FAP) is a hereditary condition that greatly increases a person’s risk of developing colorectal cancer. People with this syndrome typically develop hundreds of polyps in the colon and rectum. Cancer nearly always develops in one or more of these polyps between the ages of 30 and 50 if preventive surgery is not done. Like FAP, Gardner’s syndrome results in polyps and colorectal cancers that develop at a young age. It can also cause benign (not cancerous) tumors of the skin, soft connective tissue, and bones. Hereditary nonpolyposis colon cancer (HNPCC) develops in people at a relatively young age without first having many polyps. Women with this condition also have an increased risk of developing cancer of the endometrium (lining of the upper part of the uterus).

Recent research has found an inherited tendency to develop colorectal cancer among some Jews of Eastern European descent. Like people with FAP, Gardner’s syndrome, and HNPCC, their increased risk is due to an inherited mutation (change in DNA). This DNA change occurs much more commonly than the three other colorectal cancer syndromes, and is present in about 6% of American Jews. Additional research is needed to determine the extent to which this change increases risk. So far, there appears to be a relatively small increase in risk, much less than that caused by FAP, Gardner’s syndrome, or HNPCC.

Approximately 20 epidemiologic studies have found that people who regularly use aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) have 40% to 50% lower risk of colorectal cancer and adenomatous polyps.

There are other risk factors, such as a strong family history of colorectal cancer, which people cannot control. Even when people have a history of colorectal cancer in their family, they may be able to prevent the disease. They should ask their doctors for information and advice about prevention and early detection. For example, people with a family history of colorectal cancer may benefit from starting screening at a younger age and having screening tests done more often than people without this risk factor. Genetic tests can help determine which members of certain families have inherited a high risk for developing colorectal cancer. Most doctors recommend that people with familial adenomatous polyposis (FAP) start colonoscopy during their teens and have their colon removed during their twenties to prevent cancer from developing. The risk for people with hereditary nonpolyposis colon cancer (HNPCC) is not as great as for those with FAP. Ashkenazi Jews with the I1307K APC mutation have a slightly increased colorectal cancer risk, but do not develop these cancers at a very young age.

Among men and women, colorectal cancer is the third most common cancer diagnosed in Americans. About 93,800 new cases of colon cancer (43,400 men and 50,400 women) and 36,400 new cases of rectal cancer (20,200 men and 16,200 women) will be diagnosed in 2000.

What is the role of diet in the prevention of this disease?

A diet that consists mostly of foods that are high in fat, especially from animal sources, can increase the risk of colorectal cancer. Physical inactivity; people who do not get at least a moderate degree of physical activity have an increased risk of developing colorectal cancer. Obesity; being very overweight increases a person’s colorectal cancer risk. Having excess fat in the waist area increases this risk more than having the same amount of fat in the thighs or hips. Researchers suggest that the excess fat changes metabolism in a way that increases growth of cells in the colon and rectum, and that fat cells in the waist area have the largest impact on metabolism. Diet suggestions would include choosing most of your foods from plant sources and limiting intake of high-fat foods such as those from animal sources. A diet with five servings of fruits and vegetables every day and six servings of other foods from plant sources such as breads, cereals, grain products, rice, pasta, or beans. Many fruits and vegetables contain substances that interfere with the process of cancer formation. According to one estimate, deaths from cancers of the colon, prostate, pancreas, and breast may be reduced a whole 50% if everyone would adopt a diet that supports good health.

Is diet used in the management of the disease?

Nutrition recommendations usually stress eating

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