Colorectal Cancer Screening

March 13th, 2010Cancers, Colon Cancer, Health Screening1 comment

Colorectal cancer is very common. It is the second deadliest form of cancer among both men and women in the US.

Colorectal cancer is also the most common cancer in Singapore and about 1500 new cases are diagnosed every year. Yet the current rate of colorectal cancer screening is low. Only one in nine men aged between 50 and 70 has done a colonoscopy at least once. The figure is even lower for women at one in 13.

The Singapore Health Ministry rolled out a colorectal screening programme for Singaporeans over 50 years old to encourage more Singaporeans to screen for this cancer. Although the current survival rate of colorectal cancer has improved, the 5 year survival rate is still below the average of the OECD (Organization for Economic Cooperation and Development) countries. The low survival rate for colorectal cancer is because almost 60% of the cases are detected only in the advanced stage. It is therefore important for individuals who are above 50 years of age to go for screening.

Colon cancer is an abnormal cell growth of cells that line the inside of the colon. The colon is the last three feet or so of the human intestinal tract and is responsible for drawing fluid out of the stool before a bowel movement.

Colon cancer starts as polyps that grow on stalks or as flat patches in the colon. Over time, these polyps, which are not generally cancerous in and of themselves, will become cancerous and grow into the wall of the colon. Sometimes it spreads to other body areas, such as the liver and lungs.

If you have colon cancer, you might have no symptoms at all or you can have some of the following symptoms: pain in the abdomen, blood in the stool or black tarry stools, a change in your bowel habits or very narrow stool. You can lose weight unexpectedly if you have colon cancer. Remember that benign conditions of the colon and stomach can mimic colon cancer so you have to have a colonoscopy in order to tell if there are colon polyps or colon cancer in the large bowel.

The colonoscopy is a camera study that travels along the length of the colon, looking for areas of polyps, diverticuli or other abnormalities. If a polyp is found, it is removed through the colonoscope and then sent to the laboratory to be checked under the microscope. If cancer is found, the area of the colon that had the polyp may need further surgery if it didn’t look like the whole cancer was taken.

Screening should start at around age 50. Colonoscopies should be every 10 years and flexible sigmoidoscopy should be done every four years. Annual tests for fecal occult blood should be done to check for blood in the colon. Fecal occult immunochemistry screening tests are also done in some clinics, which test better for human blood. Rather than the flexible sigmoidoscopy, an air contrast barium enema should be done every five years.

Virtual colonoscopy may be an option. This is a CT scan of the colon that is an excellent screening test for colon cancer. It is currently not covered under insurance plans, however, and is very expensive to do. If a polyp is found on virtual colonoscopy, the individual needs to have a regular colonoscopy to have the polyps removed.