Colon polyps, explained by a colorectal surgeon
What colon polyps are, why they matter, and how they are removed.
If a colonoscopy has turned up a polyp, the question you want answered is how serious it is, and that depends entirely on the type.
Most weeks in clinic, I sit with a patient whose colonoscopy turned up a polyp they did not expect, and the first question is almost always the same: should I be worried. The honest answer is that it depends on the type, and the type we confirm after the polyp has been removed and examined under the microscope.
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The reassuring part comes first, because it is the larger part.
Most colon polyps are harmless, cause no symptoms, and are found only because someone went looking.
Colon polyps are among the most common findings at routine colonoscopy. The majority are harmless, cause no symptoms, and most people who carry them would never know without screening. That part is reassuring, and I say it first.
A smaller share of polyps are precancerous, and over years some of those can progress to colorectal cancer. That is the reason we look for them, remove them, and base your follow-up interval on what the pathology shows.
What are colon polyps?
Colon polyps are abnormal growths that develop from the inner lining of the colon (the large intestine) or rectum. They form when cells in that lining divide more than they should, producing a small projection of tissue where the wall should be smooth.
They vary in shape and size. Some are flat against the lining, some sit on a broad base (sessile), and others hang from a stalk (pedunculated). A polyp can range from a couple of millimetres to several centimetres.
The polyp itself is a finding, not yet a diagnosis. What it means for you comes from the pathology after removal.
10 to 15
Possible progression time described by HealthHub
Some polyps can progress over many years. This is a possible timescale, not a safe waiting period. HealthHub describes it on its colorectal cancer facts page. A colonoscopy can find polyps and often remove them during the same procedure. Removal is the measured half of that argument: in the National Polyp Study (Winawer et al., New England Journal of Medicine, 1993), patients whose adenomas were removed at colonoscopy went on to a 76 to 90 percent lower incidence of colorectal cancer than the three reference groups tracked.
Source: HealthHub, Singapore
A polyp forms
Often without symptoms
Possible progression
May develop over many years
Complete removal
Removes that lesion
Types of colon polyps.
How serious a polyp is depends on what type it turns out to be. Clinical classification divides polyps into two broad groups, non-neoplastic and neoplastic, and the difference shapes your follow-up plan.
Non-neoplastic polyps
Non-neoplastic polyps are generally harmless and unlikely to become cancerous. The main types are:
- Hyperplastic polyps, a common variety, usually small and found in the lower colon, with very low cancer risk
- Inflammatory polyps, which occur in patients with Crohn’s disease or ulcerative colitis, and although they are not cancerous in themselves, they signal chronic inflammation that raises overall colorectal risk. Each form of inflammatory bowel disease has its own page: Crohn's disease and ulcerative colitis.
- Hamartomatous polyps, associated with rare genetic syndromes such as Peutz-Jeghers, typically single and harmless in children but higher risk when multiple
Polyps are often removed so tissue can be examined. The removal plan depends on their size, location and appearance, as well as the risks for the patient.
Neoplastic (precancerous) polyps
Neoplastic polyps carry malignant potential, which is the reason their detection and removal matter. They include:
- Adenomatous polyps (adenomas), the most clinically significant group, including tubular adenomas, tubulovillous adenomas, and villous adenomas
- Serrated polyps, including sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs)
| Type | Group | What it means |
|---|---|---|
| Hyperplastic | Non-neoplastic | A common variety; usually small and found in the lower colon; very low cancer risk. |
| Inflammatory | Non-neoplastic | Not cancerous in themselves; they occur with Crohn's disease or ulcerative colitis and signal chronic inflammation that raises overall colorectal risk. |
| Hamartomatous | Non-neoplastic | Associated with rare genetic syndromes such as Peutz-Jeghers; typically single and harmless in children, higher risk when multiple. |
| Adenomatous (adenomas) | Neoplastic | The most clinically significant group: tubular, tubulovillous and villous adenomas. Precancerous. |
| Serrated | Neoplastic | Sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs). Precancerous. |
10mm
One size criterion for an advanced adenoma
An adenoma measuring 10 mm or more is considered advanced. Histology can also make an adenoma advanced, so size alone does not determine follow-up.
Source: US Multi-Society Task Force on Colorectal Cancer, 2020
Classification matters because it dictates follow-up. The 2020 consensus of the US Multi-Society Task Force on Colorectal Cancer sets the next colonoscopy at 7 to 10 years after one or two small tubular adenomas, 3 to 5 years after three or four, 3 years after five to ten, and 3 years after any adenoma of 10 mm or more or any with villous features or high-grade dysplasia, against 10 years after a normal colonoscopy in someone at average risk (Gupta et al., Gastroenterology, 2020). These intervals assume a high-quality examination and complete removal in an average-risk adult. Your medical history and the findings may require a different plan.
Colon polyp symptoms, and why there usually are none.
The majority of colon polyps produce no symptoms at all, which is the principal reason regular colonoscopy screening in Singapore is worth the effort. Polyps are typically found because someone went looking, not because they made themselves known.
When symptoms do appear, they are more often associated with larger polyps, or polyps that have undergone significant change. The symptoms worth bringing to a consultation are:
- Rectal bleeding, or blood in your stool, which may appear as red streaks on toilet paper, or cause stools to look dark and tarry
- Persistent changes in bowel habits, including new constipation or diarrhoea
- Mucus in the stool in larger-than-usual amounts, particularly alongside other symptoms
- Unexplained fatigue or shortness of breath, which can point to iron-deficiency anaemia from slow, occult bleeding
- Lower abdominal pain or cramping, particularly if a larger polyp is causing partial obstruction
None of these symptoms are diagnostic on their own. They are reasons to have the colon properly assessed, not to assume.
What the test involves, and what the day looks like, is on the colonoscopy page.
Do colon polyps need to be removed?
Most polyps can be removed during colonoscopy, but the method and timing depend on the polyp and the patient. Larger or complex polyps may need a planned specialist procedure. Removed tissue is examined to help determine its type and the next steps.
Found at colonoscopy
Usually while looking for something else
Removal is planned
Often at the same sitting; some polyps need a separate procedure
Sent for pathology
Which is what names the type
Your interval is set
From what the pathology shows
Colon polyp removal is called polypectomy. The technique depends on the polyp’s size, shape and position, and whether it can be removed safely during that examination:
- A wire snare is commonly used
- Cold-snare techniques remove tissue without electrocautery
- Larger or complex lesions may need other endoscopic techniques or surgery after assessment
Every polyp removed is sent for pathology. The result is what determines what happens next.
After colon polyp removal: recovery and follow-up.
Colon polyp removal recovery is straightforward for most patients. Polypectomy at colonoscopy is a day procedure, and most patients return to light daily activities within 1 to 2 days. Mild bloating or cramping after the procedure is normal and settles quickly.
Restrictions on driving, heavy lifting and strenuous activity may last longer. Follow your discharge instructions. Seek urgent care for heavy bleeding, worsening abdominal pain, dizziness or fever.
1 to 2
Days back to light daily activities, for most patients
Polypectomy at colonoscopy is a day procedure. The picture changes if a larger polyp required endoscopic mucosal resection, or if laparoscopic surgery was needed. Recovery is longer in those cases, and the specific instructions your surgeon gives you take precedence over anything written here in general terms.
Source: Dr Sulaiman Bin Yusof, clinical practice
| What was done | What recovery looks like |
|---|---|
| Polypectomy at colonoscopy | A day procedure. Most patients return to light daily activities within 1 to 2 days; restrictions on heavy lifting and strenuous activity may last longer. |
| Endoscopic mucosal resection of a larger polyp | Recovery is longer. The specific instructions your surgeon gives you take precedence over general guidance. |
| Laparoscopic or open surgery | Recovery is longer in these cases too. Follow your treating surgeon's instructions. |
What to eat after colon polyp removal
Follow the food plan on your discharge sheet. The advice depends on the size and number of polyps removed and the technique used. If you are prescribed a low-fibre diet, ask how long to follow it.
Can polyps regrow after removal?
Complete removal is the aim. Residual tissue can remain after an incomplete removal, and new polyps can develop elsewhere. Follow-up checks for these possibilities.
In the CARE study (Pohl et al., Gastroenterology, 2013), 10.1% of neoplastic polyps removed at colonoscopy were incompletely resected, and the rate rose with polyp size and for sessile serrated polyps.
Follow-up depends on the number, size and type of polyps, confidence in removal, bowel preparation and your medical history. Your doctor will give you the next date after reviewing the findings.
The exact interval is determined by your pathology results, along with the number, size, and type of polyps removed. For some patients, a single hyperplastic polyp means we are back to the standard screening cycle. For others, a high-grade adenoma or multiple advanced polyps means a closer watch.
The questions patients ask after a polyp is found.
How serious are polyps in the colon?
Many polyps are not cancerous. Adenomas and some serrated lesions can develop into cancer over time (source: United Lincolnshire Hospitals, colonic polyps and aftercare, opens in a new tab). The type, size and other findings help determine the plan. Removed tissue is examined to help establish the diagnosis and follow-up.
At what age should I start screening for colon polyps in Singapore?
Average-risk colorectal screening in Singapore starts at age 50 (source: HealthHub, Singapore, screening for colorectal cancer, opens in a new tab). If a close relative has had colorectal cancer or polyps, discuss the relative's diagnosis and age at diagnosis with your doctor; your starting age and test may differ.
Are colon polyps hereditary?
Most are not. Most polyps develop sporadically over time, related to age, lifestyle, and chance. A meaningful minority are linked to inherited conditions, such as familial adenomatous polyposis (FAP) and Lynch syndrome. A family history of polyps or colorectal cancer may affect when and how often screening is advised, and is worth flagging when we plan your assessment.
Does every polyp have to be taken out?
Most polyps found at colonoscopy are removed so the tissue can be examined. Some need a different plan because of their size, position or appearance, or the risks of removal (source: European Society of Gastrointestinal Endoscopy, polypectomy guideline update 2024, opens in a new tab). A complex polyp may need a separate procedure or referral to an endoscopist with the required expertise; surgery is considered when appropriate. Your doctor will explain the plan and how any pathology result affects follow-up.
How long does recovery take after a polyp is removed?
Most patients return to light daily activities within one to two days after polypectomy at colonoscopy. Recovery can take longer after removal of a larger polyp or surgery. Restrictions on driving, heavy lifting and strenuous activity may last longer (source: United Lincolnshire Hospitals, colonic polyps and aftercare, opens in a new tab), so follow your discharge instructions.
What should I eat after colon polyp removal?
Follow the food plan on your discharge sheet (source: North Tees and Hartlepool NHS Foundation Trust, polypectomy aftercare, opens in a new tab). The advice depends on the size and number of polyps removed and the technique used. If you are prescribed a low-fibre diet, ask how long to follow it.
What percentage of colon polyps are cancerous?
Most polyps found at colonoscopy are not cancer. Some types can develop into cancer over time. Removal and examination of tissue help establish the diagnosis, but the method and timing depend on the polyp and the patient (source: European Society of Gastrointestinal Endoscopy, polypectomy guideline update 2024, opens in a new tab). Your doctor will explain the removal plan and follow-up.
Do I need another colonoscopy after polyps are removed?
Follow-up depends on the number, size and type of polyps, confidence in removal, bowel preparation and your medical history (source: US Multi-Society Task Force, follow-up after colonoscopy and polypectomy, 2020, opens in a new tab). Your doctor will give you the next date after reviewing the findings.
Related reading
Where this leads next.
The author
Dr Sulaiman Bin Yusof
Senior Consultant Colorectal and General Surgeon, with over 20 years in surgery.
In his own words
I am a Senior Consultant Colorectal and General Surgeon in Singapore, practising at Gleneagles, Mount Elizabeth Novena, Parkway East, Mount Alvernia, and Farrer Park. I perform the colonoscopy as part of a full assessment, remove polyps where found, send them for pathology, and set your follow-up interval based on the result.
He wrote this article and is responsible for its clinical content.
- Qualifications
- MBChB (Sheffield)
- M.Med (Surgery)
- FRCSEd (General Surgery)
- Fellowship
- Peter MacCallum Cancer Centre, Melbourne
- Previously
- Former Director of Endoscopy, Changi General Hospital
- Also
- Visiting Consultant, Changi General Hospital
Disclaimer: The information here is for general informational purposes only and does not replace consultation, diagnosis, or treatment by a qualified medical professional. Symptoms vary between individuals; if any of the warning signs above apply to you, seek a clinical evaluation.
Getting seen
Most polyps are harmless. The type is what decides, and only pathology can name it.
If you have been told you have polyps, or you are due a screening colonoscopy, consult a colorectal doctor in Singapore to have it properly assessed.
Contact us on WhatsApp to arrange a consultation.
+65 8491 1525