Early Detection of Colon Cancer
by Joseph D. Tabora, M.D.
This article starts below.
Colon cancer is one of the few cancers that can be detected before symptoms develop. Checking for occult blood in the stool, having a barium study, and undergoing a flexible sigmoidoscopy or colonoscopy are steps you can do to nip colon cancer in the bud.
Natural history of colon cancer
Cancer of the colon often starts as a polyp (adenoma), a non-cancerous growth that looks like a small mushroom attached to the inside surface of the colon. When left alone over several years, polyps degenerate to cancer (carcinoma). The degeneration is called the adenoma-carcinoma sequence.
Once carcinoma is present, it grows rapidly, spreads to the lymph nodes near the colon, and eventually spreads to distant organs like the liver, lungs and bone.
Symptoms of colon cancer
Because of the function of the colon, early-stage cancer of this organ produces no obvious symptoms. As the colon normally accommodates bulky stool throughout its length, a small polyp or a beginning cancer the size of a 25-centavo coin will not affect its function and will not produce pain or massive bleeding. These small lesions may bleed a little as stool brushes over them. This hidden (occult) blood in the stool may be detected by a special stool examination.
As the cancer grows bigger, it may lead to anemia (the cancer bleeds frequently), weight loss (cancer cells compete for nutrition), and change in bowel habits (the cancer obstructs the free passage of stool).
In its advanced stage, it may produce abdominal enlargement, vomiting of fecaloid fluid and inability to pass stool. It may also produce a mass in the liver and lungs.
Prevent advanced colon cancer
Because of the absence of dramatic symptoms in the early stage, colon cancer almost always gets diagnosed in its advanced stage. Fortunately there are tests that can be done to detect colon cancer in its early stage: fecal occult blood test, proctosigmoidoscopy, flexible sigmoidoscopy, barium study and colonoscopy. The appropriate test for you will be assessed by your physician.
Who should be screened
- Adults 50 years old and above
- Adults younger than 50 years old with a family history of colon cancer
Our best chance against colon cancer is still early detection. Those at risk stand to gain the benefits of early detection and treatment.