A polyp is any mass of tissue that comes from the bowel wall and sticks out into the open space inside the bowel. They may be attached by a broad base or by a narrow stalk and vary widely in size. There is usually more than one polyp at a given site. Polyps occur most often on the lining of the colon, the part of the lower bowel that connects to the rectum.
Most polyps don't cause symptoms. When there are symptoms, rectal bleeding is the most common complaint. Cramps, abdominal pain, or a blockage may occur. Occasionally, a polyp on a long stalk may fall through the anus.
Causes and Risk Factors
About 24 percent of patients who have cancer of the large bowel will also have polyps.
A condition called familial polyposis, in which 100 or more polyps carpet the colon and rectum, is genetic and results from a genetic mutation.
Rectal polyps can be felt during an examination by a doctor. Most often they are discovered when a patient undergoes endoscopy. Because rectal polyps are often multiple and may be present with cancer, a complete colonoscopy is necessary. Polyps can also be diagnosed using barium enema X-rays or double-contrast (pneumocolon) examination.
Polyps should be completely removed by surgery.
If a polyp is cancerous, how it is treated will depend on how deeply the cancer has invaded the polyp and how well differentiated the cancerous tissue is from the healthy tissue. In some cases, it may be necessary to remove a segment of the colon and rejoin the sections.
After treatment, it is usually recommended that a person have their colon inspected two times a year using a colonoscopy or a barium enema. Any new lesions discovered should be removed.
After two exams have shown no more new lesions, a follow-up colonoscopy can be done every two to three years.