Polyps

Introduction

A polyp is defined as an overgrowth of tissue which protrudes from a lining anywhere in the body. Polyps in the colon are usually of two different types – those that appear as a bump in the lining of the colon, or those that are flat or sessile. Colorectal polyps are very common with approximately one in seven people having them. In most cases they are not cancerous, however they may develop into cancer, although this often takes a long period of time (years).

Symptoms

Most polyps do not produce any symptoms at all. If they are large, they may cause rectal bleeding, mucous in bowel motions, or a change in bowel habit.

It is not unusual for polyps to be found in the course of examination for other reasons.

Causes

Colorectal polyps form due to DNA or gene changes within the cells of the lining of the bowel. This causes overactivity of the cells, resulting in the formation of polyps. Polyps can occur at any age, however is more common over the age of 50. Polyps are not inherited from family members, unless they are associated with rare inherited bowel cancer syndromes, such as Familial Adenomatous Polyposis Syndrome (FAP).

Tests & Diagnosis

Faecal occult blood testing (FOBT) kits may yield a positive result in the presence of moderate to large sized polyps. As mentioned previously however, most polyps are often discovered incidentally as part of an examination for other reasons. The most sensitive method of detecting colorectal polyps is a colonoscopy.

Treatment

When detected at colonoscopy, all polyps should be removed where possible and sent for testing as there is no way of telling whether a polyp is cancerous or not during the examination (even though the risk of a cancerous polyp is relatively small). Where a polyp has been found to be pre-cancerous, another colonoscopy will be required to check that further polyps have not re-developed in the bowel. More information on the removal of polyps on our section on polypectomy.