Does every polyp turn into cancer?

No. Most polyps do not have time to turn malignant within a person's lifetime, and small hyperplastic polyps of the sigmoid colon and rectum carry a very low risk. It is impossible to predict exactly which polyp will turn malignant, although the risk is judged by type, size, location and dysplasia, so adenomas and serrated lesions are removed rather than watched.

I was told my polyp is too large for colonoscopy and I need surgery. Is that right?

Not always. Size alone is rarely a reason for bowel resection: in experienced endoscopy centers many large benign lesions are removed without surgery after expert assessment. Surgery is needed when there are signs of deep invasion or endoscopic removal is impossible or unsafe. Before agreeing to a resection, it is worth getting the opinion of such a center.

The polyp was removed and the histology shows cancer. What next?

It depends on the pathology report. If the polyp was removed in one piece with clear margins and no adverse features, surveillance is often enough. If the tumor is at the margin, poorly differentiated, or there is vascular invasion or deep submucosal invasion, a bowel resection with lymph nodes is discussed, weighing its benefit and risk. The decision is made by the multidisciplinary team.

Is surgery mandatory in familial adenomatous polyposis?

In the classic form — usually yes: there are too many polyps to remove endoscopically, and without surgery cancer develops almost inevitably. In the attenuated form the approach may differ. The operation is preventive and is planned before the polyps turn malignant; its timing and extent — removal of the colon or of the whole large bowel — are decided individually, based on the number and size of the polyps, including those in the rectum.

How often should colonoscopy be done after polyp removal?

The interval depends on the number, size and structure of the removed lesions. After a large polyp removed in pieces, early follow-up is needed so that no residual tissue is missed; after one or two small low-risk adenomas some patients need only routine screening. The exact schedule is set by the doctor from the histology report.

Colon polyps: when colonoscopy is enough and when surgery is needed

Most colorectal cancers start from a polyp that grows over years. Removing a polyp in time substantially lowers the risk of cancer. In most cases a colonoscopy is enough for this, without surgery. A surgeon is needed for a smaller group of patients: when a lesion cannot be removed endoscopically in a safe way, when cancer with a risk of lymph node spread is found in a polyp that has already been removed, or when there are hundreds of polyps because of a hereditary syndrome.

Kateryna Valikhnovska, MD, surgical oncologist, during a laparoscopic operation — The laparoscopic stage of an operation: the lights are dimmed because the surgeon works from the camera image on the monitor.

What counts as a precancerous condition

Not every polyp is dangerous: small hyperplastic polyps in the sigmoid colon and rectum carry a very low risk of turning malignant. Precancerous lesions are those from which cancer can develop:

adenomas — tubular, tubulovillous and villous; the risk of malignant change is higher in large adenomas, those with a villous structure and those with high-grade dysplasia;
serrated lesions — sessile serrated lesions and traditional serrated adenomas; often flat, located on the right side and easy to miss at colonoscopy;
laterally spreading tumors — not a separate histological type but a growth pattern: flat lesions that spread along the bowel wall and can cover several centimeters;
hereditary polyposis syndromes — above all familial adenomatous polyposis: hundreds or thousands of adenomas grow in the large bowel, and without treatment cancer develops almost inevitably.

Lynch syndrome stands apart — an inherited predisposition to cancer of the bowel and other organs. There are few polyps, but malignant change can happen faster, so after genetic confirmation a dedicated colonoscopy surveillance program is needed.

Are there symptoms

Usually not. Most polyps do not hurt and do not interfere with bowel movements, so they are found at colonoscopy — either for screening or for another reason. Large lesions can cause blood or mucus in the stool and a change in bowel habits, and occult bleeding can lead to iron deficiency anemia.

A positive fecal occult blood test is a reason for colonoscopy even if you feel well. The absence of complaints says nothing about the absence of polyps.

Tests needed

A complete colonoscopy with good bowel preparation — examination up to the cecum; with poor preparation small and flat lesions are easy to miss, and the examination has to be repeated.
Assessment of the lesion by the endoscopist — size, shape, location and surface pattern under enhanced imaging: these are the features used to suspect cancer and to choose how to remove the lesion.
Histology — after removal the whole polyp is examined. Whether to biopsy a large lesion before planned endoscopic removal is decided by the endoscopist: an unnecessary biopsy can cause scarring and make removal harder.
CT, and pelvic MRI for rectal lesions — if cancer is suspected or confirmed.

If hereditary polyposis or Lynch syndrome is suspected, genetic counseling is added to the plan — it determines the extent of surgery and the testing of relatives.

When endoscopic removal is enough

Most polyps are removed during colonoscopy, without any incisions. Small ones with a snare, large flat ones by endoscopic mucosal resection (EMR), and lesions suspected of superficial invasion in one piece (including by endoscopic submucosal dissection, ESD) so that the pathologist can assess the margins.

In experienced endoscopy centers many even large benign lesions are removed endoscopically after expert assessment. So if surgery is offered only because of the size of a polyp, it is worth getting the opinion of such a center: a bowel resection is a bigger operation with a higher risk than endoscopic removal.

Surgery is needed when:

there are signs of deep invasion into the bowel wall, in which case endoscopic removal would not be radical;
the lesion cannot be removed endoscopically in a safe way because of its location, size or scarring from previous attempts;
cancer with adverse features is found in a polyp that has already been removed — see below;
familial adenomatous polyposis or another syndrome is diagnosed in which there are too many polyps for endoscopic control.

When cancer is found in a polyp

Sometimes a polyp is removed endoscopically and the histology shows cancer that has grown into the submucosa. The key question then is whether the tumor could have spread to lymph nodes, which an endoscope does not remove. The answer comes from a detailed pathology report:

whether the tumor was removed completely: whether it is present at the resection margin, including the deep margin, or closer to it than acceptable;
the grade of differentiation of the tumor;
whether there is tumor in lymphatic or blood vessels;
the depth of submucosal invasion and the degree of tumor budding.

If there are no adverse features and the polyp was removed in one piece with clear margins, surveillance is often enough. If there are — surgical resection of the corresponding bowel segment with its lymph nodes, as for cancer, is discussed, weighing the risk of lymph node involvement against the risk of the operation itself and the patient's condition. If the polyp was removed in pieces, the margins cannot be assessed, and the decision takes this into account. The final plan is set by the multidisciplinary team.

How the operation is performed

When cancer is confirmed — including in a polyp already removed — or reasonably suspected, the extent is the same as for cancer: a section of bowel is removed together with its mesentery and lymph nodes. If the lesion is considered benign but cannot be removed endoscopically, the extent is decided individually: hidden invasive cancer cannot be ruled out before full histology, and lymph nodes are needed for accurate staging. Before surgery the site of the lesion is often marked endoscopically with a special dye so that it can be found during the operation.

In familial adenomatous polyposis the operation is preventive: the large bowel is removed before the polyps turn malignant. Either the colon is removed and the small bowel is joined to the rectum (ileorectal anastomosis), or a proctocolectomy is performed — removal of the colon and rectum with a pouch made from the small bowel and joined to the anal canal. The choice depends on the involvement of the rectum, the genetic variant, age and the possibility of further surveillance. The timing of surgery is decided individually, based on the number and size of the polyps.

When the location of the lesion and previous operations allow, the operation is done laparoscopically — through a few small incisions.

A surgeon needs to know not only how to operate but also when an operation is not needed. If a polyp can be removed endoscopically, that is the better path for the patient.

Kateryna Valikhnovska, MD, surgical oncologist

Recovery after surgery

After endoscopic removal most patients return to normal life within a few days; the risk of complications — bleeding and perforation — depends on the size, location and method of removal, and warning signs (blood in the stool, abdominal pain, fever) should be reported to the doctor at once.

After a bowel resection care follows the enhanced recovery after surgery (ERAS) protocol: early mobilization, early return to eating, controlled pain relief. After removal of the whole large bowel for polyposis, bowel movements become more frequent; the body adapts gradually over months, helped by diet and medication.

Follow-up

Whether and when a follow-up colonoscopy is needed depends on the number, size and histology of the lesions and the quality of the first examination: after a large polyp removed in pieces, early follow-up is scheduled so that no residual tissue is missed, while after small low-risk adenomas some patients can simply return to routine screening. The schedule is set by the doctor.

In familial adenomatous polyposis surveillance is lifelong: after surgery the remaining rectum or the pouch is monitored, as well as the duodenum, where adenomas also form — upper endoscopy includes an examination of the major papilla. The patient's relatives are offered genetic counseling and testing for the variant found in the family.

What to bring to the consultation

the colonoscopy report with a description and, if possible, photos of the lesion;
the histology report of the removed polyp — with the margins, grade, vascular invasion and depth of invasion if cancer was found;
the tissue blocks and slides — for review in another laboratory;
CT or MRI discs, if these have already been done;
information about cancer and polyps in the family — who, at what age, which site.

If some documents are missing, that is no reason to postpone the consultation — some of the tests can be done on site.

The consultation is free of charge. How it goes and how long it takes is described on the page “Oncologist Consultation”.