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Early Detection Saves Lives

Colon cancer is the second most deadly, but one of the easiest to detect. In its earliest stages, it’s also one of the most curable.

Who is at Risk for Colon Cancer?

In general, colon cancer is not a young person's disease. In fact, more than nine out of 10 patients are over 50. However, some people have inherited conditions that make them vulnerable to colon cancer at a much younger age.

For instance, people with familial adenomatous polyposis -- a rare condition in which hundreds of polyps form in the colon -- can develop colon cancer in their 20s. If left untreated, almost everyone with this problem will develop cancer by age 40.

Research reported in Science indicates that a mutation of a gene called BLM, most often found in people of Ashkenazi Jewish ancestry, may double or triple a person's risk of colorectal cancer. Scientists emphasize, however, that the causes of colorectal cancer are complex, and the gene mutation is only one possible factor.

If you've had colon cancer before, you're an obvious target for another bout of the disease. You're also more likely to develop the cancer if you have a history of polyps, Crohn's disease, or ulcerative colitis.

Although researchers are not yet sure how big a role genes may play in colorectal cancer, you might have an increased risk if a close family member has the disease.

About 20 percent of all patients have a family history of the disease. Your risk is increased if a first-degree relative (i.e., parents who had cancer before age 60, or a sister or brother) has had colon cancer.

According to the American Cancer Society, having diabetes increases your risk of developing colorectal cancer by 30 percent.

Heavy smokers may also be especially vulnerable to colorectal cancer, in addition to lung cancer and heart disease. A study of more than 17,000 Swedish twins published in the International Journal of Cancer found that longtime smokers were three times more likely than nonsmokers to develop colorectal cancer.

If you're a woman with a history of ovarian, uterine, or breast cancer, you also run a slightly increased risk of getting colorectal cancer.

If you're overweight, losing those extra pounds can help reduce your risk of colon cancer. A government study of over 13,000 people, published in the American Journal of Epidemiology, found that those with a body mass index (BMI) between 24 and 26 had an 86 percent greater risk of colon cancer when compared to those with a BMI of 22 or less. (BMI is a standard measurement to determine if a person's weight is appropriate to his height, and a BMI of 30 is considered obese.)

Can Colorectal Cancer Be Prevented?

Regular colon screening and removal of polyps will provide powerful protection against colon cancer. The American Cancer Society estimates that 90 percent of all colorectal cancer cases and deaths could be prevented by the timely use of screening tests, along with changes in diet and physical activity.

If you're younger than 50, but have had polyps, inflammatory bowel disease, or someone in your family has had colorectal cancer, you should ask your doctor for a screening before you reach that age.

Once you turn 50, the American Cancer Society suggests you follow one of the following screening test options:

• An annual fecal occult blood test (FOBT) plus flexible sigmoidoscopy every 5 years (the two tests in combination are more effective than either alone)
• A flexible sigmoidoscopy every 5 years
• An annual fecal occult blood test (FOBT)
• Colonoscopy every 10 years
• Double-contrast barium enema every 5 years

Any of these options can help catch problems before they get too serious -- check with your doctor to determine the best option for you.

A study reported at a meeting of the American Association for Cancer Research suggested that a simple baby aspirin may be an effective weapon against colon cancer for patients who have had precancerous polyps or colon cancers surgically removed.

In the study of over 1,100 people, patients who took a baby aspirin a day reduced their risk of developing further precancerous polyps by 20 percent, while patients with colon cancer reduced their risk of recurrence by 40 percent.

Interestingly, the study found that a baby aspirin -- 81 milligrams -- was more effective than a standard aspirin, which is 325 milligrams. However, doctors don't advise a daily aspirin for everyone over 50 and the National Cancer Institute emphasizes that it is not clear whether aspirin lowers the risk of cancerous tumors.

In fact, aspirin and other anti-inflammatory drugs like naproxen and ibuprofen carry their own risks, including heart attack, stroke, and bleeding in the stomach and intestines.

Researchers are also studying several vaccines that could help prevent colorectal cancer from coming back after treatment. Vaccines are currently available only in clinical trials.

Estimates vary, but there is no doubt that smoking is linked to colon cancer. So if you smoke, you have another good reason to quit.

As far as diet goes, eating lots of fruits and vegetables and limiting the amount of red meat you eat will lower your risk of colon cancer. The American Cancer Society (ACS) recommends eating five or more servings of fruits and vegetables a day, and eating whole grains rather than processed ones. Since obesity is also linked to colorectal cancer, the ACS says you should eat healthy, keep your weight down, and exercise regularly.

Limiting alcohol consumption is also a good idea for high-risk individuals. One French study of subjects who already had at least one colon polyp found that those who were heavy drinkers (those who consumed an average of 117 grams of alcohol a day for an average of 22 years) were likely to develop further precancerous polyps and colon cancer. (To get an idea of how much alcohol 117 grams is, 100 grams equals about 6 to 8 cans of beer, 6 to 8 glasses of wine, or 6 to 8 shots of hard liquor.)

The message to take home is simple: If you're a target for colon cancer or over age 50, get screened. If everybody followed that advice, a major killer would quickly lose its power.

What are the Symptoms of Colorectal Cancer?

Even as it grows and spreads, colorectal cancer is often a silent disease. Many people never suspect a problem until they undergo a routine screening test.

When colon cancer does cause symptoms, they are often easy to overlook. Many patients simply have constipation or diarrhea or bouts of both (symptoms that resemble those of a non-cancerous disorder known as irritable bowel syndrome).

Other possible symptoms include bleeding from the rectum, blood in the stools, stomach cramps, and strong urges to have bowel movements when it's not necessary.

What is Colorectal Cancer?

Colorectal cancer is a cancer found in the colon or rectum. Like all forms of cancer, colorectal cancer gets its start when cells begin dividing uncontrollably. The cells then form tumors that can spread to other parts of the body.

Most colorectal cancers arise from small growths called polyps. Polyps come in two types, hyperplastic and adenomatous. Hyperplastic polyps are tiny and have no potential to turn cancerous. But adenomatous polyps can be dangerous, depending largely on size. Growths less than 5 millimeters across almost never cause trouble, but growths more than 2 centimeters across have a 50-50 chance of becoming cancerous within 10 to 15 years.

Not all polyps are cancerous, but if they're adenomatous, they should still be removed and sent to the pathology lab for study.