Colon cancer involves the large intestine (colon), the lower part of the digestive tract, while rectal cancer specifically involves the last six inches of the colon. Together, they're often called colorectal cancers .
These cancers occur when cells lining your colon or rectum become abnormal and grow uncontrollably. Colorectal cancer  is the second leading cause of cancer-related death in the U.S., with about 50,000 deaths and 150,000 people diagnosed annually.
You May Not Have Symptoms
Early on, colorectal cancer generally has no symptoms. By the time people do have symptoms, the cancer is usually advanced and very hard to treat. Regular screening  with colonoscopies allows more cancers to be found earlier, when the disease is easier to cure.
The U.S. Preventive Services Task Force recommends colonoscopies  every 10 years starting at age 50 if you’re healthy and have no symptoms or risk factors. Once a polyp is found, it is recommended that you have a colonoscopy every 3-5 years. Some patients need to have a colonoscopy before they are 50, depending on various risk factors.
There are 4 basic tests for colon cancer: a stool test (to check for blood); sigmoidoscopy (inspection of the lower colon; colonoscopy (inspection of the entire colon); and double contrast barium enema. All 4 are effective in catching cancers in the early stages, when treatment is most beneficial.
A colonoscopy  allows your doctor to detect growths, polyps, inflammation and ulcers in your colon. During this procedure, your doctor uses a thin, flexible, hollow, lighted tube called a colonoscope with a tiny video camera on the end to search for polyps or other abnormalities. Your doctor may remove small polyps or take small tissue samples for closer examination.
Obviously, the more your doctor is able to see, the more polyps she can find and remove.
A New “Eye” on Colon Cancer Prevention
The Brooklyn Hospital Center  is the only hospital in New York to offer the Third Eye® Retroscope® device, a breakthrough technology in the fight against colorectal cancer.
Operating like a car’s rearview mirror, the Retroscope is inserted through a standard colonoscope to give your doctor a backward view of your colon. This view often reveals lesions hidden behind folds where they can’t normally be seen, helping your doctor find up to 23-25% more pre-cancerous polyps than a standard colonoscope alone.
Sushil Duddempudi, MD, Director of Interventional Endoscopy , has performed hundreds of these procedures and can be reached at (718) 852-8375 to schedule a colonoscopy.