Serrated polyposis syndrome (SPS)

How is SPS diagnosed and where does the name come from?

SPS polyps are normally diagnosed at colonoscopy, which is often carried out due to someone presenting to their GP with symptoms (such as persistent diarrhoea and/or bright red rectal bleeding). The polyps in SPS are termed “serrated” because of their appearance when examined under a microscope. Most serrated polyps are not cancerous, however, they may become cancerous if they are not monitored and treated when necessary.

What causes SPS?

Currently we do not know what causes SPS but think that there may be an inherited element because people can be affected at a young age and also because a family history of SPS or bowel cancer is found in some people with the condition. No genetic cause has been found but we are investigating this as one of our current research projects.

As there is no genetic blood test for SPS, the only way to determine if someone has SPS is to carry out a colonoscopy. Colonoscopy is the best test for detecting polyps in SPS as other methods of examining the colon (e.g. a CT scan) are not as accurate and cannot remove the polyps.

How is SPS treated?

Most people with SPS have their treatment with regular colonoscopy. A blue dye is often sprayed into the colon when looking for SPS polyps as they can be quite flat and the blue dye makes them easier to see. Polyps larger than 5mm will be removed. Sometimes more than one colonoscopy will be required at initial diagnosis to remove all the larger polyps from the colon and rectum.  The time interval between colonoscopies will depend on the number and size of the polyps found, as well as features of the polyp when assessed under a microscope. Usually patients are assessed every 1-2 years.

For some individuals, it may not be possible to safely control the polyps with colonoscopies and their consultant may recommend that an operation is performed. This is not common, however and a surgeon would discuss this further and provide further information. SPS only affects the large bowel and no other screening is required if you are diagnosed with the condition.

Should my family be screened?

We currently recommend that first degree relatives (siblings, parents and children) of an individual with SPS should be referred to their local genetics centre or to The Polyposis Registry for discussions about long term colonoscopic screening. This should start at the age of 25 years, or if older, from the time that their relative was diagnosed with SPS. It should be repeated every 5 years if normal and we would recommend colonoscopic screening withe dye spray to ensure that small or flat polyps are not missed. These recommendations may change as we learn more about this condition.