The colonoscopy is not the only screening tool for colon cancer. If you're not familiar with the other procedures, it's not surprising. A report in the July 2009 issue of American Journal of Preventive Medicine reported that most primary care physicians don't discuss all the screening options for colon cancer endorsed by the American College of Gastroenterology (ACG) and usually just recommend colonoscopy.

Screening methods for colon cancer vary in effectiveness, safety, invasiveness and cost and the ACG just updated its recommendations in 2009. If it's time for your colon cancer screening, here's what you should know.

Sigmoidoscopy. A sigmoidoscopy is similar to a colonoscopy. Your physician examines the lower third of the colon (instead of the whole colon) with a lighted scope and camera. This procedure generally requires less bowel preparation and patients remain awake. If your physician finds polyps or abnormal tissue, he can remove them during the sigmoidoscopy, so it's a preventative as well as a screening tool. The National Cancer Institute reports sigmoidoscopy misses two-thirds of existing tumors in women, twice the number missed in men, so it's less effective.

Fecal Occult Blood Test (FOBT). Cancers or polyps in the colon may bleed and the FOBT detects tiny amounts of blood in your stool. The FOBT is only a screening tool and cannot prevent colon cancer. According to the National Cancer Institute, a FOBT every one to two years in 50 to 80-year olds helps reduce colon cancer deaths by 15 to 33 percent. The ACG recommends the newest version of the FOBT.

Double-contrast barium enema. Your physician will insert air and a liquid with barium and air into the rectum and colon. Barium is a silver-white metallic compound that shows up on X-ray images. This procedures misses small polyps and only detects 30 to 50 percent of cancers, so the ACG doesn't recommend it anymore.

Digital Rectal Exam (DRE). As part of a physical, your physician examines your lower rectum for abnormalities with a gloved finger.

Virtual colonoscopy. A virtual colonoscopy scans the interior surface of the colon and converts the pictures into two and three-dimensional images on a computer screen. A recent study showed that virtual colonoscopies are effective at detecting very small polyps.

Pill camera. Capsule colonoscopy, or swallowing a pill with a tiny camera, may be the future of colon cancer screening. Pilot studies suggest this procedure, which physicians now use to view the small intestine, has potential despite current limitations.