A polyp is an abnormal growth of tissue rising from the lining of the large intestine and protruding into the intestinal canal. Some polyps are flat, and others are attached to a stalk.
It is one of the most common conditions affecting the colon and rectum, and it occurs in 15-20% of the adult population. While some polyps are non-cancerous, the natural progression of certain polyps to cancer is well established. Some polyps,if left alone, may gradually progress to colorectal cancer.
Most polyps produce no symptoms and are often discovered incidentally. Some polyps can produce bleeding, mucous discharge, change in bowel habits etc. The only way to know is to undergo colorectal screening with colonoscopy.
An effective way to screening for polyps is to undergo a colonoscopy. This can be diagnostic and therapeutic (i.e. small polyps can be removed during endoscopy). Alternatives to screen the colon include barium enema, CT colonography, stool occult blood test, etc.
In colonoscopy, the doctor looks directly at the colon lining to inspect for polyps. This is performed with flexible instrument which is inserted into the colon via the anus, and permits inspection of the entire colon to the terminal ileum. The risks of colonoscopy include: colonic perforation (1:1000), bleeding, infection, etc. Colon perforation, if it occurs, would require emergency operation.
In barium enema, the doctor examines the colon indirectly using x-ray. X-rays are taken as the lining of the colon is coated with a barium solution. Polyps can be identified in the x-ray films. In CT Colonography, the lining of the colon is also inspected using x-rays in a specialized CT scanner.
No. While checking stools for microscopic blood is important, a negative test does not rule out the presence of polyps. It is best to have a complete colon inspection done as the presence of one polyp usually indicates the possibility of additional polyps.
There is no foolproof way of predicting the malignant potential of a polyp. As such, complete removal of all polyps is advised. Small polyps can be removed during colonoscopy, while larger polyps may require surgery.
Once a polyp is completely removed, its recurrence is very unusual. However, the same factors that allowed it to form are still present. New polyps will develop in at least 30% of patients with a history of polyps. Regular and more frequent examination of the colon and rectum is then recommended.
