They are small fungal-like abnormalities of the intestine that can be flat or have a stem, they can be single or multiple.
They can vary from less than 2 millimeters to more than 50 millimeters in diameter. Polyps larger than 1 cm in diameter are at higher risk of being cancerous.
Risk factors include a family history of colon cancer or polyps .
There are some inherited disorders that are associated with the formation of polyps including:
- Gardner syndrome, a variant of adenomatous polyposis.
- The genetic condition of Peutz-Jeghers syndrome, a hamartomatous polyposis.
- Juvenile gastrointestinal polyposis.
- Adenomatous polyposis, a family disease.
- Lynch syndrome or hereditary colorectal cancer.
In most cases, colorectal polyps do not cause symptoms, however, they can cause intermittent bleeding or the passage of mucus with bowel movements. If they are large, they can block the passage of waste material.
Adenomas account for about 70 percent of all colorectal polyps removed as part of the colonoscopic examination.
Adenomas are present in 30 percent of all adults over the age of 50.
They occur most often in the rectum and sigmoid colon.
Adenomas are described as pedunculated when they grow on a stalk that connects the head of the polyp with the wall of the intestine and the planes are called sessile and grow directly on the wall of the intestine.
About 85 percent are tubular (they grow into microscopic tubes); 5 percent are hairy (forming finger-like projections, or fronds); and 10 percent are tubulovillous (intermediate structures that contain both growth patterns).
These polyps differ in their structure, texture, and microscopic characteristics; they also differ in their potential for cancerous change.
Invasive cancer develops in about 5 percent of all tubular polyps (also called adenomatous).
Villous polyps are less common, but about 40 percent of them become cancerous.
Cancer develops in about 22 percent of all tubulovillous polyps.
The most common colorectal types, called hyperplastic polyps or hyperplastic mucosal tags, are harmless. Many cancers of the large intestine are believed to arise from polyps.
Therefore, removing these growths (polypectomy), often through a sigmoidoscope or colonoscope, is one way to prevent colorectal cancer.
Because new polyps develop in almost half of all patients who have such growths removed, careful monitoring is necessary.
Causes of intestinal polyps
Siblings and parents of patients with colon polyps are at increased risk for colon cancer, especially when the polyp is diagnosed before age 60 or, in the case of siblings, when a parent has had colon cancer.
About 90 percent of all colon cancers arise from polyps in the colon.
If doctors can prevent polyps from developing in the first place, they could reduce the incidence of cancer.
In general, most doctors encourage people to eat a low-fat, high-fiber diet, eat more fruits, vegetables, chicken, and fish, and eat less red meat.
Smoking can also be a risk factor for colon cancer.
In some studies, greater body mass was associated with an increased risk of adenomas leading to colon cancer.
Symptoms of Intestinal Polyps
Many polyps are asymptomatic; the larger the injury, the more likely it is to cause symptoms. Rectal bleeding is the most common complaint.
The blood is bright red or dark red, depending on the location of the polyp, and the bleeding is usually intermittent.
Some polyps, particularly large villous adenomas, can secrete large amounts of mucus that are released through the rectum.
When a person’s symptoms suggest that there may be cancerous growths in the colon or rectum, the doctor will ask about the patient’s medical history and then perform a complete exam.
In addition to checking general health signs (temperature, pulse, and blood pressure), the doctor usually performs the following tests:
- Sigmoidoscopy: An internal exam of the lower large intestine (colon), using an instrument called a sigmoidoscope.
- Colonoscopy: An internal examination of the colon (large intestine), using an instrument called a colonoscope.
- Virtual colonoscopy.
- Barium enema.
Treatment of intestinal polyps
Polyps of the colon and rectum must be treated because they can become malignant later on.
Small polyps can be removed with an electrocautery trap passed through a rigid or flexible sigmoidoscope.
Large, sessile, soft, velvety lesions in the rectum are usually villous adenomas, and these tumors have a high malignant potential and must be completely removed.
Depending on your medical history, age, and risk factors, your doctor will recommend how often you might detect colon cancer.
Even how often you should perform the fecal occult blood test and how often you should have a flexible sigmoidoscopy, colonoscopy, or other tests.