Colon Polyps

Colon polyps are clusters of cells that form on the lining of the colon or rectum. While most colon polyps are harmless, some are malignant or may become malignant. It is important to have regular colon screenings and to have any existing polyps removed, particularly because colon polyps most often do not result in symptoms. Left undetected, they are more likely to become cancerous and colon cancer is more likely to be fatal when discovered at a later stage.

Types of Colon Polyps

There are three types of colon polyps:

  • Adenomatous
  • Serrated
  • Inflammatory

Approximately two-thirds of all colon polyps are adenomatous. Although only a small percentage of these are malignant, almost all malignant polyps are of this type. Small serrated polyps in the lower colon, known as hyperplastic polyps, are rarely malignant, but serrated polyps in the upper colon are more likely to be precancerous or cancerous. Inflammatory polyps are typically the result of a flareup of inflammatory bowel disease.

Risk Factors for Developing Colon Polyps

Certain factors increase an individual's risk of developing colon polyps. These factors include:

  • Being age 50 or older
  • Being African-American
  • Having a family history of polyps or colon cancer
  • Having uterine or ovarian cancer before the age of 50
  • Obesity, lack of exercise, smoking, excessive alcohol use
  • Having Type 2 diabetes
  • Having ulcerative colitis or Crohn's disease

Regular colon screenings are recommended for everyone 50 years of age or older. Those with a family history of colon cancer are usually instructed to begin screenings earlier and to have them more frequently than the general population.

Symptoms of Colon Polyps

Small polyps do not usually cause symptoms, but larger ones may cause some of the following:

  • Rectal bleeding
  • Bloody or discolored bowel movements
  • Constipation or diarrhea
  • Narrow stools
  • Pain, nausea or vomiting
  • Anemia

While such symptoms often have other causes, changes in bowel habits that last for over a week and stools that are streaked with red or black should always be reported. Patients may have rectal bleeding from hemorrhoids, suffer nausea from another, often benign, intestinal condition, or be anemic because of a nutritional deficiency, but colon polyps should always be ruled out as a cause.

Diagnosis of Colon Polyps

A number of tests may be administered to check for colon polyps. These include:

  • Digital rectal exam
  • Barium enema
  • Flexible sigmoidoscopy
  • Colonoscopy
  • Virtual or CT colonoscopy
  • Fecal blood test
  • DNA testing of stool

The colonoscopy, although it requires an unpleasant bowel preparation, has the advantage that almost any polyp detected can be removed during the same procedure. Once removed, the polyp is microscopically examined to determine what type of polyp it is and whether or not it is malignant.

Treatment of Colon Polyps

Usually, a colon polyp can be removed during a colonoscopy or sigmoidoscopy. If this is impossible due to the size or location of the polyp, minimally invasive surgery may be necessary. In the case of rare inherited conditions, patients may require a total proctocolectomy during which both the colon and rectum are removed to protect them from life-threatening malignancy.

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