Medical Oncologist
CION Cancer Clinics
Serrated polyposis syndrome: what it is and what happens next | CION Cancer Clinics
Serrated polyposis syndrome is diagnosed when colonoscopy finds many serrated polyps, a type that can slowly turn into bowel cancer. It raises your risk and your close relatives' risk, but unlike most polyposis conditions it is rarely caused by a single inherited gene fault. This page explains how it is diagnosed, what is known about its causes, and what regular checks look like. At CION Cancer Clinics, our oncologists plan screening and care for families with an inherited cancer syndrome, explained in plain words.
NG
Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
17+specialists on panel
15,000+patients treated
35+centres across Telangana & AP
4.8★ / 800+Google rating
On this page
- What is serrated polyposis syndrome?
- What causes serrated polyposis?
- What happens after the diagnosis?
- The words you will meet, in plain language
- How is it different from other polyposis syndromes?
- Four things families tell us, and what is actually true
- What this page cannot tell you
- Common questions about serrated polyposis
The short answer
What is serrated polyposis syndrome?
Serrated polyposis syndrome is diagnosed when colonoscopy finds many serrated polyps in the large bowel. These polyps can turn into bowel cancer, so the condition raises your risk and calls for regular checks. Unlike most polyposis conditions, it is usually not caused by one known gene fault.
What a serrated polyp is
Under the microscope, these polyps have a saw-tooth edge, which gives them their name. Small ones in the last part of the bowel, the rectum, are very common and usually harmless. Others, called sessile serrated lesions, are flat and pale. They sit higher up in the bowel, are easy to miss, and can slowly become cancer.
How the diagnosis is made
Doctors follow World Health Organization rules, and there are two routes. The first is at least five serrated polyps above the rectum, each at least five millimetres across, with two of them a centimetre or more. The second is more than twenty serrated polyps of any size across the whole bowel, with at least five above the rectum. Polyps from all your colonoscopies are added together, so the diagnosis is often made over time.
The diagnosis rests on counting polyps. A gene test is not needed to make it.What lies behind it
What causes serrated polyposis?
For most people the honest answer is that nobody knows. These are the pieces that are understood.
Mostly unexplained
In most people with serrated polyposis, no single inherited gene fault is found. It seems to arise from several smaller influences acting together. That is also why the risk to relatives is raised but lower than in conditions caused by one strong gene.
Smoking
Smoking is linked to serrated polyps and to this syndrome. Studies so far suggest the link is real, though they cannot yet say how much stopping lowers the risk. Chewing tobacco and gutka have been studied far less, so the effect of these is not known.
A rare gene fault
A small number of families carry a fault in a gene called RNF43. When one is found, relatives can be tested for it directly. Those who do not carry it can then be spared the extra colonoscopies.
Other conditions that can look similar
Some inherited polyposis conditions can also produce serrated polyps. A gene test is often offered to rule them out.
Most often checked for
- MUTYH-associated polyposis
- Lynch syndrome, when a cancer is present
- Other rare polyposis genes
Not sure whether this applies to you?
Ask an oncologistWhat comes next
What happens after the diagnosis?
-
Clearing the bowel
Your gastroenterologist removes all the polyps that matter. This can take more than one colonoscopy, especially if some are large or flat.
-
A gene test to rule out other conditions
A blood test checks for MUTYH and other polyposis genes. A negative result is the usual outcome and does not change the diagnosis.
-
Regular colonoscopy
Once the bowel is clear, checks continue at intervals your gastroenterologist sets, usually shorter than for the general population.
-
Close relatives are advised
Brothers, sisters, parents and children have a raised risk of bowel cancer themselves. They are usually offered colonoscopy earlier than routine screening would start.
-
Surgery only if colonoscopy cannot keep up
An operation is considered when polyps are too many or too large to control, or when a cancer is found. For most people it is never needed.
On your report
The words you will meet, in plain language
- Hyperplastic polyp
- The commonest serrated polyp. Small ones in the rectum are usually harmless, but they are still counted towards the diagnosis.
- Sessile serrated lesion
- A flat serrated polyp, often in the right side of the bowel. This is the type most likely to turn into cancer if left.
- Dysplasia
- Cells that have started to look abnormal. It is a warning sign, not cancer, and it shortens the gap between checks.
- Proximal colon
- The first part of the large bowel, far from the back passage. Flat serrated polyps are more common here.
- Dye spray colonoscopy
- A colonoscopy where a harmless dye or special light is used to show flat polyps more clearly.
- First-degree relative
- A parent, brother, sister or child. These are the relatives most often offered earlier colonoscopy.
Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Side by side
How is it different from other polyposis syndromes?
Serrated polyposis
Most other polyposis syndromes
Usually no single gene fault is found
A gene fault is found in many families
Relatives are checked by colonoscopy, based on family history
Relatives can be tested for the family's exact fault
Most people are diagnosed as adults
Several begin in childhood or the teenage years
The diagnosis rests on counting polyps over time
The diagnosis can rest on a gene result
Commonly believed
Four things families tell us, and what is actually true
"Hyperplastic polyps are harmless, so mine do not matter."
A few small ones in the rectum usually do not. Many serrated polyps higher in the bowel are a different matter, and they are what this diagnosis is about.
"The gene test was negative, so my family is in the clear."
In serrated polyposis a negative gene test is the usual result. Close relatives still carry a raised risk and are usually advised to have colonoscopy earlier than routine.
"Once my bowel is cleared, I can stop having colonoscopies."
New polyps keep forming. Regular checks are what keep the cancer risk down, so they continue even after a clear result.
"Stopping smoking now will make no difference."
Smoking is linked to serrated polyps, and stopping is good for the bowel and the rest of the body. The exact benefit for this syndrome is still being studied.
Being straight with you
What this page cannot tell you
It cannot tell you whether you meet the criteria. That needs a gastroenterologist to add up the polyps across every colonoscopy and pathology report you have had. Reports from different hospitals often need to be read side by side. Some reports describe polyps only as hyperplastic or serrated without a size, and the specialist may need to ask the laboratory for more detail before deciding.
It cannot interpret a gene result
If a gene test finds a variant, what that specific variant means is a question for the counsellor who ordered the test. A result the laboratory cannot yet classify should not change your care on its own.
Who this does not apply to
One or a few small hyperplastic polyps in the rectum are very common, and they are not serrated polyposis. Most people with a single serrated polyp need only routine follow-up. Flat serrated polyps are easy to miss, so a good bowel preparation and an experienced endoscopist matter. If you live in a district, it can be worth travelling for these checks. Ask whether Aarogyasri or Ayushman Bharat covers them at your centre.
If you have several colonoscopy reports and are unsure what they add up to, bring them together to one specialist.Questions we are asked
Common questions about serrated polyposis
Is serrated polyposis inherited?
Sometimes it runs in families, but usually no single gene fault is found. Close relatives still have a raised risk of bowel cancer and of the syndrome itself. That is why they are offered earlier colonoscopy even without a gene result.
Do my brothers and sisters need a colonoscopy?
Usually yes, earlier than routine screening would start. Your gastroenterologist will suggest the timing based on your own findings and the rest of the family history. Children are usually advised in adult life.
Why test my genes if the result is usually negative?
To rule out other conditions, such as MUTYH-associated polyposis, that can look similar. Those conditions change what your relatives are offered. A negative result simply keeps the diagnosis as serrated polyposis.
How often will I need a colonoscopy?
After the bowel is cleared, checks continue at regular intervals that are shorter than for the general population. The exact gap depends on how many polyps are found each time. Your gastroenterologist will set it.
Does this mean I will get bowel cancer?
No. Your risk is raised, but regular colonoscopy finds and removes polyps before they turn into cancer. Most people who keep to their checks do not develop bowel cancer.
Will I need surgery?
Most people do not. Surgery is considered when colonoscopy cannot keep the polyps under control, or when a cancer is found. It is one option among several, discussed with a specialist team.
Why does the bowel preparation matter so much?
Flat serrated polyps are pale and easily hidden by stool. A poorly cleaned bowel can mean polyps are missed, and the test may need repeating. Follow the preparation instructions closely, even if they are unpleasant.
Where do I start?
Collect every colonoscopy and pathology report you have. Note who in the family has had polyps or bowel cancer. Take both to a gastroenterologist or genetic counsellor. The CION helpline can tell you who to see.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Sources
- Gut (British Society of Gastroenterology) — Guidelines for the management of hereditary colorectal cancer from the BSG, ACPGBI and UKCGG
- National Cancer Institute — Genetics of Colorectal Cancer (PDQ) - Health Professional Version
- NCCN — Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric
- NHS — Bowel polyps
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Juvenile polyposis syndrome explainedThe other polyposis condition in this group, for comparisonSurveillance in juvenile and serrated polyposisWhat regular colonoscopy involves over the yearsWhen polyposis needs surgeryThe uncommon situations where an operation is discussedSerrated polyposis syndrome and its geneticsRNF43 and why a gene is rarely found
Talk to us
Has a colonoscopy found many serrated polyps?
Tell us what your colonoscopy and pathology reports say and who else in the family has had polyps or bowel cancer. We will help you work out who should review them. One helpline serves every CION centre.