Colon Cancer

Any adult can have colorectal cancers (cancers of the colon and rectum), but most of these cancers are found in people age 50 or older. People with a personal or family history of this cancer, or who have polyps in their colon or rectum, or those with inflammatory bowel disease are more likely to have colon cancer. Also, eating a diet mostly of high fat foods (especially from animal sources), being overweight, smoking and being inactive can make a person more likely to have colon cancer.

SCREENING AND PREVENTION - What you can do

Colon cancer almost always starts with a polyp. Testing can save lives by finding polyps before they become cancer. If pre-cancerous polyps are removed, colon cancer can be prevented. Eating a low-fat diet that is rich in fruits and vegetables may also make you less likely to have this cancer.

The American Cancer Society recommends one of the following testing options for all people beginning at age 50:

Tests that find polyps and cancer

• Flexible sigmoidoscopy every 5 years*, or
• Colonoscopy every 10 years, or
• Double-contrast barium enema every 5 years*, or
• CT colongraphy (virtual colonoscopy) every 5 years*

Tests that primarily find cancer

• Yearly fecal occult blood test (FOBT)**, or
• Yearly fecal immunochemical test (FIT)**, or
• Stool DNA test (sDNA), interval uncertain**

*If the test is positive, a colonoscopy should be done.

**The multiple stool take-home test should be used. One test done by the doctor is not adequate for testing. A colonoscopy should be done if the test is positive.

RISK FACTORS
A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lungs, larynx (voice box), mouth, throat, esophagus, kidneys, bladder, colon, and several other organs.

But risk factors don't tell us everything. Having a risk factor, or even several risk factors, does not mean that you will get the disease. And some people who get the disease may not have any known risk factors. The following are the risk factors for colon cancer:

• Age
  Younger adults can develop colorectal cancer, but the chances increase markedly after age 50; More than 9 out of 10 people diagnosed with colorectal cancer are older than 50.
• Personal history of colorectal polyps or colorectal cancer
  If you have a history of adenomatous polyps (adenomas), you are at increased risk of developing colorectal cancer. This is especially true if the polyps are large or if there are many of them.
• Personal history of inflammatory bowel disease
  Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is a condition in which the colon is inflamed over a long period of time.
• Family history of colorectal cancer
  Most colorectal cancers occur in people without a family history of colorectal cancer. Still, as many as 1 in 5 people who develop colorectal cancer have other family members who have been affected by this disease.
• Inherited syndromes
  About 5% to 10% of people who develop colorectal cancer have inherited gene defects (mutations) that cause the disease.
• Hereditary non-polyposis colon cancer (HNPCC)
  HNPCC, also known as Lynch syndrome, accounts for about 3% to 5% of all colorectal cancers.
• Racial and ethnic background
  African Americans have the highest colorectal cancer incidence and mortality rates of all racial groups in the United States. The reasons for this are not yet understood. Jews of Eastern European descent (Ashkenazi Jews) have one of the highest colorectal cancer risks of any ethnic group in the world. Several gene mutations leading to an increased risk of colorectal cancer have been found in this group. The most common of these DNA changes, called the I1307K APC mutation, is present in about 6% of American Jews.
• Lifestyle-related factors
  Several lifestyle-related factors have been linked to colorectal cancer. In fact, the links between diet, weight, and exercise and colorectal cancer risk are some of the strongest for any type of cancer.