Intestinal Polyps | Polyps, Symptoms, and Their Impact on Colon Cancer Risk

A predisposition to developing colorectal polyps can be partly hereditary. However, these hereditary polyposis conditions account for only a small percentage of all diagnosed cases of colorectal polyps.

Most colorectal polyps tend to occur in the second half of life. They are likely the result of random mutations in the tissues of the colon wall (sporadic occurrence).

Experts suspect that diet and lifestyle play a role in the development of colorectal polyps. There is also evidence of a familial clustering of these polyps.

Risk factors for the development or malignant transformation of colorectal polyps include

• a diet low in fiber and high in fat,
• lack of physical activity,
• being overweight, and
• smoking and alcohol consumption.

However, proving a clear causal relationship—as opposed to a mere association—between these factors and the occurrence of colorectal polyps is complicated. Links between

• being overweight, a sedentary lifestyle, and long-term smoking on the one hand, and
• the risk of adenomas, on the other hand,

have been convincingly demonstrated. Furthermore, there is a link between the risk of colorectal polyps and other diseases. These include, in particular, diabetes and inflammatory bowel diseases.

Small colorectal polyps are almost always completely asymptomatic. Larger polyps can lead to blood in the stool—which usually goes unnoticed—and/or noticeable mucus in the stool.

As the polyps grow larger, irregularities in bowel movements (diarrhea or constipation) as well as abdominal pain may occur.

Colonic polyps can be reliably diagnosed through a colonoscopy. In Germany, health insurance companies cover preventive colonoscopies for the early detection of colorectal cancer for

• men aged 50 and older and
• women aged 55 and older

every ten years and is covered even without a specific medical indication. A fecal occult blood test is recommended annually starting at age 50 and is covered by health insurance. A positive result should prompt a colonoscopy for further evaluation.

If symptoms occur or there is an increased family risk, a colonoscopy is covered by health insurance at any age. Possible symptoms include, for example,

• visible blood in the stool,
• unexplained abdominal pain,
• noticeable changes in bowel habits.

During a colonoscopy, a flexible colonoscope is inserted into the colon through the anus. The scope contains a light source and a camera that continuously transmits images of the colon wall to a monitor.

For a colonoscopy, the bowel must be as completely empty as possible. To achieve this, the patient prepares by taking a highly effective laxative, which effectively cleanses the bowel.

The examination of the entire intestinal mucosa, from the rectum to the junction between the large and small intestines, takes about 25 minutes. The procedure is usually performed under light sedation or general anesthesia. This procedure carries very low risk.

If a colon polyp is detected during the colonoscopy, it is removed immediately whenever possible. Depending on the size and shape of the polyp, various techniques are available for this purpose. Generally, the necessary instruments are advanced through the colonoscope’s tube to the intestinal wall. The following video explains the principle: 

Pedunculated polyps are usually removed by placing a wire loop around the stalk and tightening it. This method is also called snare polypectomy. An electric current passing through the wire cuts the polyp away from the intestinal wall and simultaneously cauterizes (seals) the wound.

Sessile polyps (non-pedunculated, flat, and broad-growing polyps) can also be removed with a wire loop. However, this often has to be done in several pieces. The risk of either failing to remove the polyp completely or causing significant damage to the intestinal wall is relatively high.

In recent years, improved methods for removing sessile colorectal polyps have become available: endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). In both procedures, the sessile intestinal polyp is lifted away from the intestinal wall by injecting saline solution or another specially formulated injection solution beneath it.

In EMR, the abnormal tissue is then grasped with a snare and removed. In ESD, the polyp is incised around its perimeter with a special blade inserted through the endoscope and then detached.

For large polyps, the alternative to ESD is surgical removal. The procedure can be performed using a minimally invasive approach (keyhole surgery/MIC) or through traditional open surgery.

Removal of colorectal polyps using an electric snare during a colonoscopy © phonlamaiphoto | AdobeStock

After the removal of the colorectal polyp(s), a thorough microscopic examination of the tissue is performed. If a polyp is found to be neoplastic (i.e., with the potential for malignant transformation) and already exhibits more or less pronounced changes compared to the characteristics of normal tissue, follow-up colonoscopies are scheduled at regular intervals.

This ensures excellent conditions for the timely diagnosis and removal of any additional polyps.

The risk of recurrence of adenoma-type colorectal polyps is reduced, depending on

• the type, size, and number of polyps removed during the initial procedure,
• the degree of dysplasia detected in the biopsy, and
• the removal technique (in pieces or as a whole)

is estimated at 10 to 20 percent. Recurrent adenomas can also be removed without complications in over 90 percent of cases.

The development of colon polyps is influenced by age, genetic predisposition, and lifestyle.

No, many colon polyps are benign, but some types can become malignant.

Colonoscopy is the most important procedure for diagnosing colon polyps and for screening.

Yes, new colon polyps can develop. That’s why follow-up exams are important.

A balanced diet, exercise, and screening help reduce the risk of colorectal polyps.