Colorectal cancer (of the colon or rectum) is the third leading cause of cancer-related deaths in the U.S., although when caught early, colon cancer is highly curable.  The American Cancer Society (ACS) guidelines call for colon screening to begin at age 50 for both men and women-or earlier if there's a history of chronic inflammatory bowel disease or a strong family history of colon cancer. This usually involves an annual fecal occult blood test and a flexible sigmoidoscopy every five years. But cancer experts say the best screening method is colonoscopy, in which the whole colon is examined with a colonoscope, a long flexible tube with a small video camera attached on the end, which is inserted through the rectum into the colon. To ensure a painless procedure, an intravenous sedative is given to relax patients or if they prefer, they can also be put under a temporary general anesthesia.

However, many people often put off getting recommended colonoscopies because they're uncomfortable with the idea of the colonoscopy exam. Now, they may have another option. Recent clinical trials comparing the results from virtual colonoscopy, or computed tomographic (CT) colonography, and traditional colonoscopy have found that virtual colonoscopy is about as effective as traditional colonoscopy in spotting large precancerous polyps and colorectal cancer.

In a virtual colonoscopy, a CT scan of the colon and rectum is performed using X-rays to create two- and three-dimensional images, which the doctor can examine for polyps or other possible precancerous changes. However, the ACS warns that while virtual colonoscopies may give those at average risk for colon cancer an alternative to traditional colonoscopies, they aren't recommended for people at high-risk for colon cancer. For high-risk individuals-those with a strong family history of colon cancer-colonoscopy is still the gold standard in finding colorectal cancer early.

Another downside to virtual colonoscopies is that they're not as effective in picking up smaller, possibly precancerous polyps as traditional colonoscopies are and if abnormalities are found, patients will have to go back for a standard colonoscopy to remove suspicious lesions. Plus, virtual colonoscopies require the same amount of bowel preparation, including liquid diets and strong laxatives taken a day before the test, as traditional colonoscopy, which people often claim is more bothersome than the actual test.

The bottom line: Talk to your doctor about when you should start colorectal screenings and which type would be most beneficial for you.