Serrated Polyposis syndrome

Serrated Polyposis syndrome

Serrated Polyposis syndrome (SPS) is defined by the occurrence of multiple serrated polyps in the colon and is associated with an increased risk of bowel (colorectal) cancer.

Serrated polyps are different from common adenomatous polyps, although these can also be present. They also tend to be flat (sessile), making them more difficult to see during a colonoscopy. They have had different names over the years such as hyperplastic polyps, metaplastic polyps, sessile serrated adenoma and serrated adenomas.

Serrated Polyposis syndrome is defined by the World Health Organisation (WHO) as occurring when there is:
  • either at least 5 serrated polyps proximal to the sigmoid colorectum with 2 or more greater than 10mm in size
  • or more than 20 serrated polyps of any size distributed throughout the colorectum.
Serrated Polyposis is associated with a lifetime risk of risk of colorectal cancer of 15 to 35% in the absence of colonoscopy screening. For comparison, the population risk of colorectal cancer is 6 to 12% lifetime. Also, in SPS the cancers may occur at a younger age.

Genetic testing in Serrated Polyposis syndrome

The genetic cause of SPS is not yet know. Research is ongoing. Genetic testing to exclude other causes of hereditary colon cancer or hereditary polyposis is usually recommended, especially if there is mixed polyposis or colon cancer at a young age.

Management of Serrated Polyposis syndrome

For individuals who have been diagnosed with SPS:

  • Ccreening colonoscopy to remove all polyps greater than 5 mm performed every 3 to 6 months.
  • Then, the colonoscopies are done every 1 to 3 years depending on polyp load.
  • If there are so many polyps that they can't all be removed safely, a colectomy may be recommended.

The likelihood of a colon cancer developing when this screening is followed is <1%.

Low dose aspirin has been shown to reduce the risk of polyps forming. Patients should consider 100mg enteric coated aspirin or half a usual aspirin for at least 2 and a half years from age 50. Because aspirin can cause bleeding, patients should discuss the risks and benefits with their GP before starting aspirin.

Close relatives (parents, brothers and sisters and children) of individuals with SPS are at increased risk of polyps and colon cancer. They should also start colonoscopy screening at age 40. The colonoscopies can be done every 5 years, unless polyps are detected. If polyps are present, the screening should be personalised.

Does this sound like you or your family?

Has Serrated Polyposis syndrome been detected in you or a blood relative?

Make an appointment with Dr Hilda High at Sydney Cancer Genetics. It is a confidential opportunity to discuss your personal and family history of cancer. Genetic testing can be organised and will be bulk billed if you meet the Medicare testing criteria.