Colon cancer is the poster child for the lifesaving potential of preventive screening: these types of tumors are readily detectable and increasingly curable when caught early.

Trouble is, the very thought of a colonoscopy is enough to make most people a little queasy. That’s got a lot to do with why this preventable, treatable, and ultimately beatable disease is the third leading cause of cancer deaths in the United States.

That’s because the tumors in the colon begin as non-cancerous growths called polyps.

“Colon cancer is one of the few preventable cancers. The detection and removal of colon polyps can prevent colon cancer,” says Joanne A.P. Wilson, MD.

Early testing allows physicians to identify and easily remove these trouble spots before they develop into full-fledged cancer.

Screening is important not only because it is so effective, but also because colon cancer can be silent while it progresses -- these tumors may not produce any detectable symptoms until they’ve advanced to a life-threatening stage.

Fighting the Quease Factor

Colonoscopy -- the procedure Katie Couric underwent on The Today Show in 2000 -- has long been the gold standard for catching colorectal cancer, but the list of effective screening tests doesn’t begin and end there.

Duke oncologists suggest that men and women should have some type of screening generally starting at age 50: yearly testing to check for blood in the stool, a flexible sigmoidoscopy every five years, or a colonoscopy every 10 years. And when it’s your health at stake, once a decade isn’t too much to ask.

The American Cancer Society recommends that patients age 50 and older should have CT colonography (virtual colonoscopy) every five years.

Here’s a breakdown of the four major colon-cancer screening procedures:

Fecal occult blood tests analyze stool samples for blood, which may signal polyps or cancer. They involve placing small amounts of stool on special cards that are examined under a microscope. Most primary care physicians perform the tests. Eating too much vitamin C or iron could muddle the results, so you will need to regulate your diet in the days leading up to the test. How often? Every year.

Flexible sigmoidoscopy is a procedure in which a physician looks at the lower third of the colon and surrounding areas with a small, tube-like camera. Performed in a doctor’s office with minimal sedation, sigmoidoscopy will detect most colon cancers. However, if polyps are detected, a full colonoscopy might be in order. Complication risks are minimal. How often? Every three to five years.

Colonoscopy is no walk in the park, but it remains the best way to visualize the entire colon. It involves threading a luminous tube into and around the colon to detect abnormalities. The preparation can be cumbersome -- you need to clear your bowels beforehand, which usually involves a short-term liquid diet and taking heavy laxatives or other drugs. The risk of side effects is higher than in other tests, although still fairly low for most patients. How often? Every 10 years.

Virtual colonoscopy is a less invasive alternative to the standard procedure. Though it involves the same preparation protocol as traditional colonoscopy, the procedure itself uses a CT scan to produce pictures of the colon for analysis. Data on the accuracy of virtual versus normal colonoscopies have been mixed -- and, as with sigmoidoscopy, any irregularities mean you’ll also have to undergo a full colonoscopy. Still, the procedure carries less risk for complications and doesn’t involve IVs or sedation. How often? Every 10 years.

When the Test Is Positive

What if your screening reveals tumors in your colon? Removal of the tumors themselves can be done through laparoscopic surgical techniques, which means small incisions, reduced pain, and a speedy recovery time. Recent treatment advances are making surgical cure possible for more and more patients -- even those with advanced-stage cancers.

Michael Morse, MD, noted that when colon cancer spreads to the liver or lungs, Duke doctors are now able to shrink those tumors down and remove them. A host of new chemotherapy and biologic therapy agents has eased the treatment experience and improved survival rates of patients with more advanced forms of colon cancer. Physicians used to have just one chemotherapy drug at their disposal; they now have seven.

Hedging Your Bets: What You Can Do Now

Consistent, healthful diet and exercise habits paired with awareness of any changes in your body will always be your best tools to fight and detect colon cancer -- and most other cancers, as well.

• Keep it moving: Studies have shown that moderate exercise, in addition to all its other health benefits, can cut your risk of developing colorectal cancer by nearly 50 percent.
• Eat colorfully: Large population studies have shown that diets full of folate, calcium, and vitamin D are associated with lower rates of colon cancer.
• Be attentive: If you notice any irregularities in your bowel habits, blood in your stool, or abdominal pain, see your doctor immediately. If colon cancer is producing these symptoms, it already may be at an advanced stage.
• Know when to be screened: Begin periodic screening at age 50, or earlier if you have inflammatory bowel disease, certain genetic disorders such as Lynch syndrome, or a family history of polyps or colon cancer. If an immediate relative has been diagnosed with colon cancer, begin screening at least 10 years before you reach the age at which your relative was diagnosed.