Colorectal Polyps

Small Clumps on the Colon
Polyps Colon
By Dr. Tan Wah Siew
Colorectal polyps are growths that appear on the inner lining of the colon and rectum. They are fairly common and incidence increases with age.

Why is treatment of colorectal polyps important?

Polyps are precancerous lesions. Many studies have proven that colonoscopy and removal of polyps decreases the incidence of colorectal cancer. Countries with colorectal cancer screening programs have reported a significant drop in colorectal cancer cases and deaths. This is due to early detection of colorectal polyps with colonoscopy, the removal of which prevents the development of cancer.

Why do polyps develop?

The etiology is multi-factorial, with both environmental and genetic factors at play. These include:

  • Age

    The incidence of polyps increases with increasing age.
  • Lifestyle factors:

    • Diet high in fat, processed food and red meat
    • Diet low in fibre
    • Smoking
    • Obesity
  • Genetic factors

    Genetic factors increase the risk of development of colorectal polyps. An individual with a personal history of polyps, or a family history of colorectal polyps or cancer, is at higher risk of developing polyps.

Certain genetic conditions lead to development of polyps at a younger age. These genetic conditions include:

  • Familial adenomatous polyposis (FAP)
  • Peutz-Jeghers syndrome (this condition also has small bowel polyps)
  • Juvenile polyposis syndrome
  • MYH-associated polyposis (MAP)
  • Serrated polyposis syndrome

What symptoms do polyps cause?

Polyps do not usually cause symptoms, unless they have become quite large, in which case, they may cause:

  • Bleeding
  • Change in bowel habits
  • Abdominal pain
  • Iron deficiency anemia
  • Bowel obstruction
  • Develop into cancer.

What is the treatment for polyps?

The treatment of polyps involves performing a colonoscopy and removing the entire polyp. The removed polyp is then sent for histological examination to determine if it is benign, or if malignant change has already occurred. Depending on the number and size of polyps removed, a follow up colonoscopy will be recommended anywhere from 1 year to 5 years later. If there are cancer cells found in the polyp, surgery may be required (see section on Colorectal Cancer).

Transanal Endoscopic Resection of Rectal Polyps

Rectal polyps that are too large to be removed during colonoscopy, as well as early stage rectal cancers can be excised and removed via the anus. Traditionally, this was performed open. However, with the advent of transanal endoscopic equipment, transanal endoscopic resection allows rectal polyp removal to be performed under better vision and with improved accuracy.

During surgery, a special device that seals up the rectum and allows the maintenance of pneumo-rectum (where carbon dioxide is insufflated into the rectum) is inserted through the anus. This device also allows the insertion of instruments like a camera, grasping forceps and cutting devices. The pneumo-rectum and the high definition camera allow better vision, resulting in surgery performed with better accuracy.