The statistics are staggering. Colon cancer is the second leading cause of cancer death in industrialized countries and the most common fatal cancer in nonsmokers. In 2005, the American Cancer Society estimated 145,290 new cases of colon cancer were diagnosed in the USA and 56,290 Americans died from colorectal cancer. In Rhode Island, 650 people were diagnosed with this terrible disease. The numbers for 2006 are expected to be similar.

This translates to more than 150 Americans dying from colon cancer every day. Each married couple has a 1 in ten chance that either spouse will be diagnosed with colon cancer. The health care cost of colon cancer has been estimated to exceed $5 billion per year.

The great tragedy is that most of these cancers can be detected early when curable or even prevented with proper screening. The good news is that prevention and early detection and intervention can reduce colon cancer death by more than 90%.

However, most people are reluctant to talk about this deadly disease. With the diagnosis of public figures such as President Ronald Reagan, and baseball players Eric Davis and Daryl Strawberry, awareness about colon cancer began to increase. Katie Couric, motivated by her husband's death from colon cancer, shed light on this awkward subject on the Today Show and many witnessed her colonoscopy on television. President Bush's colonoscopy in the summer of 2002 also focused attention on proper screening to prevent colon cancer.

Most colon cancers develop from benign polyps. Polyps are growths that arise from the cells that form the lining of the colon (also called the large intestine). The development from normal cells to polyps to cancer generally occurs over many years and results from an accumulation of genetic alterations in the DNA of the cells that line the colon. These genetic alterations or mutations allow the cells to grow in an uncontrolled fashion leading to polyp formation.

If these polyps are left alone, some can grow larger and accumulate enough mutations to progress into colon cancer. The cancer can cause symptoms such as bleeding, altered bowel movements, pain and fatigue (from anemia). Unfortunately, by the time someone has symptoms, the cancer may have spread outside the intestine to the liver and lymph nodes making a surgical cure more difficult.

Polyps, in general, do not cause symptoms. Fortunately, polyps can be detected and removed early before they have a chance to grow into colon cancer. The risk of polyps and colon cancer increases with age and most patients diagnosed with colon cancer are over age 50.

Other risk factors include a family history of colon cancer or polyps, sedentary lifestyle, smoking, and high fat intake. Exercise, calcium, aspirin, and folic acid all appear to decrease colon cancer risk.

Recent studies showing the superior effectiveness of colonoscopy compared to other screening methods in detecting and preventing colon cancer have led many health plans and Medicare to provide coverage for this important test.

Prior to these studies, screening in average risk individuals relied on less effective tests like testing the stool for blood (hemoccult or guiac cards), sigmoidoscopy which can evaluate only the lower third of the colon, or barium enema which is less accurate in detecting polyps and cancers than colonoscopy.

Colonoscopy involves taking laxatives the day before the procedure to cleanse the bowel of stool. The preparation is very important because if the colon is not cleaned out enough, polyps and other lesions can be missed. On the day of the procedure, a short acting sedative is given through an iv (this is called conscious sedation - not general anesthesia), and a qualified physician inserts a fancy tube with a light (a colonoscope) into the rectum and colon. This allows the physician to see the inside lining of the entire colon and remove any polyps encountered. The actual procedure takes under an hour and is done as an outpatient. Because of the sedation, patients aren't allowed to drive that day but generally feel fine shortly after the procedure and can resume normal activities the next day. Most patients experience no discomfort and joke the laxative preparation was the worst part. Because colonoscopy is an invasive procedure, there are rare risks including bleeding and perforation (causing a hole in the colon that requires surgery). Fortunately these risk in recent studies are less than 1 in a thousand and even lower with more experienced colonoscopists. Although colonoscopy is currently the best screening test available, it cannot prevent 100% of colon cancers (however, again, most experts believe it can prevent more than 90%).

There are also new technologies for screening including "virtual colonoscopy" and stool DNA testing in development. These are still generally unproven and being evaluated and are not yet widely available nor, in the vast majority of cases, covered by insurance. With CT colography ("virtual colonoscopy"), high-resolution, 2- and 3-D images of the colon are obtained after a patient's scanning by a Helical CT scan. Current drawbacks include: it is not accurate for small or flat polyps; if a polyp is detected, a full colonoscopy to remove the polyp is still required; a laxative bowel prep is required; most patients experience some discomfort (especially younger, healthier patients) because of air put into the colon prior to taking images of the colon with the CT; and the costs are high and most insurance companies don't provide coverage for CT colography yet. There is also no data on the risks associated with radiation exposure from CT colography.

The American College of Gastroenterology currently recommends screening colonoscopy every ten years beginning at age 50 for average risk individuals as the preferred screening strategy to prevent colon cancer. For patients with higher risk factors such as a family history of colon cancer or a previous personal history of polyps, earlier and more frequent screening with colonoscopy is recommended. For African Americans the recommendation is to begin screening at age 45.

The most import message to take home from this sixth annual "March is Colon Cancer Awareness Month" is that colon cancer is preventable with proper screening. Waiting for the signs and symptoms of colon cancer results in a diagnosis made too late for a cure in about 50% of patients.

For more information about the benefits of colon cancer screening and the options available, speak to your doctor. National guidelines and additional information can be found online at websites including: the American Cancer Society (www.cancer.org), the American College of Gastroenterology (www.acg.gi.org), National Digestive Disease Information Clearinghouse (www.niddk.nih.gov), the Cancer Research and Prevention Foundation of America (www.preventcancer.org), US Preventative Service Task Force/Agency for Health Care Policy and Research: Colon Cancer Screening (http://www.ahrq.gov/clinic/uspstf/uspscolo.htm) and the National Colorectal Cancer Research Alliance of the Entertainment Industry Foundation (www.eif.nccra.org).

We welcome your comments on the issues and concerns that Dr. Shah has raised. You may address your comments to Maureen@ricancercouncil.org and we will post them appropriately on our website.

IT IS EASIER TO PREVENT CANCER THAN TO TREAT IT.

If you found this information helpful, please consider making a donation to the Rhode Island Cancer Council so we may continue adding content to our website and providing valuable services to Rhode Island residents. Please click the Donate icon to the left to make a donation via credit card or your PayPal account.

See also: