Understanding, diagnosing and treating a condition that affects up to 20% of the adult population: polyps.
One of the most common conditions affecting the large intestine, which comprises the colon and rectum, polyps are anomalous growths that develop from the intestine’s internal lining. While some are flat, others have a stalk. Although most polyps are harmless, certain polyps may turn cancerous.
Most polyps are asymptomatic, and can be detected during a colon examination (more on this later). Some polyps in the rectum can be found during a rectal examination, when the doctor inserts a finger through the anus and feels the polyp. Some polyps can cause bleeding, mucous discharge, a change in bowel habits or, rarely, abdominal pain.
Types of polyps
The two most frequently occurring types of polyps are adenomatous polyps and hyperplastic polyps.
- Adenomatous polyps These can advance to cancer. Usually reported as low, moderate or severe dysplasia (abnormal growth of cells or tissues), these can turn cancerous following severe dysplasia.
Adenomatous polyps can also be categorised as tubular adenoma, villous adenoma or tubulovillous adenoma, with villous adenoma carrying a higher risk of cancer. Also, the larger the polyp, the higher the risk of cancer; reports reveal that up to 50% of polyps measuring more than 2cm are cancerous.
- Hyperplastic polyps These were previously thought to never turn malignant. However, recent studies have suggested that there is an increased cancer risk when a large number of hyperplastic polyps are accompanied by one large hyperplastic polyp.
Diagnosis and treatment
Polyps are diagnosed either by colonoscopy, barium enema or CT colonoscopy. As there is no way to predict the cancer potential of a polyp, all polyps should be removed. Most can be removed during colonoscopy, either by catching and cutting them with a wire loop or destroying them via cauterisation. Occasionally, when a large polyp cannot be removed via the methods mentioned above, surgery is required.
In some cases of large flat polyps, the doctor may adopt a more conservative approach and leave behind a bit of polyp tissue rather than risk cutting or burning a hole in the colon. Under these circumstances, it is safer to leave some of the polyp tissues at the edges and complete the removal at a later date.
A polyp does not recur following complete removal. However, new polyps will develop in up to 30% of people who have had them. Patients with polyps need repeated colonoscopy to detect and treat new ones.
Based on the type and nature of the polyps, the doctor will advise the patient on appropriate follow-up protocols. Most involve colonoscopy at a subsequent date and stool occult blood tests between colonoscopy sessions.