Darmpolypen im Darm

What are intestinal polyps?

Intestinal polyps are small growths of the intestinal lining that can occur in the colon or rectum and protrude into the intestinal lumen. Most of these mucosal protrusions are benign and cause no symptoms. However, some intestinal polyps, especially adenomatous polyps , can develop into colorectal cancer over the years. This is precisely why it is so important to detect them early and remove them if necessary. Intestinal polyps are not uncommon – between 10 and 30% of people develop polyps in their intestines at some point in their lives.

Definition and types of polyps in the intestine

Intestinal polyps are mucosal protrusions that extend into the intestine and can occur in various shapes and sizes. They arise from abnormal cell growth in the intestinal lining and can be either benign or potentially malignant. There are several types of polyps that differ in their structure, origin, and potential for malignant transformation. The most common are:

  • Adenomatous polyps (adenomas): These polyps originate from glandular cells of the intestinal mucosa and are considered precancerous lesions because they can develop into colorectal cancer over time. There are three main types of adenomas: tubular, villous, and tubulovillous adenomas. The likelihood of malignant transformation increases with the size and the amount of villous components in the tissue.

  • Hyperplastic polyps: These polyps are usually small, have a low potential for malignant transformation , and frequently occur in the distal colon or rectum. They arise from increased cell proliferation but rarely lead to malignant change.

  • Serrated polyps: These polyps have a serrated appearance and can be divided into different subgroups. Sessile serrated adenomas (SSA) and traditional serrated adenomas (TSA) have a higher risk of developing into cancer, while hyperplastic serrated polyps are usually harmless.

  • Inflammatory polyps: These occur frequently in chronic inflammatory bowel diseases such as Crohn's disease or ulcerative colitis. These polyps are usually a consequence of persistent inflammation and do not themselves carry a high risk of malignant transformation, but can serve as a marker for an increased risk of cancer .

  • Hamartomatous polyps: These rare polyps arise from tissue malformations and often occur in the context of genetic syndromes such as Peutz-Jeghers syndrome or juvenile polyposis syndrome. Some of these polyps carry an increased risk of cancer .

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Why do intestinal polyps develop?

The development of colon polyps is influenced by various factors. Firstly, genetic predisposition plays a significant role – people with a family history of colon cancer or polyps have a considerably higher risk. Secondly , lifestyle and diet can also have an impact. Inflammatory bowel diseases can also increase the risk of developing colon polyps. A low-fiber diet, high consumption of red meat, smoking, and excessive alcohol consumption are considered contributing factors. Furthermore, studies show that lack of exercise and being overweight also increase the risk.

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Do colon polyps cause symptoms?

Colonic polyps often go unnoticed because they don't cause any symptoms. Symptoms only appear when they reach a certain size or bleed. Blood in the stool is a possible warning sign, sometimes visible, but often only detectable in a laboratory. Some people also notice changes in bowel habits —sudden diarrhea or persistent constipation without an apparent cause. Abdominal pain, bloating, or unexplained weight loss should also be taken seriously.

Are colon polyps dangerous?

Not every polyp develops into cancer, but certain types carry a higher risk . Adenomatous polyps can develop into malignant colorectal cancer over years if they are not removed in time. Approximately 5 to 10 percent of these polyps can become malignant within ten years. Since everyone has a higher probability of developing colorectal polyps with increasing age, taking advantage of colorectal cancer screening programs is crucial for protecting one's health.

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Diagnosis of colon polyps

The diagnosis of intestinal polyps is usually made through an endoscopic examination, most often via colonoscopy . This method allows the doctor to directly examine the lining of the intestine and identify any polyps. In certain cases, additional examinations such as CT scans, MRI scans, or capsule endoscopy may be necessary. Before the actual examination, a medical history and rectal examination are performed to gain an initial impression. A test for genetic alterations and occult blood in the stool, such as the ColoAlert stool test , can also provide indications of the presence of intestinal polyps. Since the likelihood of intestinal polyps increases with age, regular colonoscopies or stool tests are recommended as a preventative measure starting at age 50.

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When is the removal of intestinal polyps necessary?

If polyps are discovered during a colonoscopy , the doctor decides on the next steps depending on their type, size, and number . Small polyps can often be removed directly during the examination – a painless procedure that is usually performed on an outpatient basis. Larger polyps or those with an abnormal cell structure may require further examination or surgical removal. The removed tissue is then examined pathologically to determine the type of polyp.

Disease progression and prognosis of intestinal polyps

The course of disease associated with intestinal polyps depends heavily on their type and size. Small polyps often remain asymptomatic and are only discovered incidentally, while larger polyps can lead to bleeding or other complications. The prognosis is generally good if intestinal polyps are detected and removed early. Regular checkups are crucial to ensure that no new polyps develop and that existing polyps are treated promptly. This helps minimize the risk of malignant transformation and the development of colorectal cancer.

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Colorectal cancer screening: How can polyps be detected early to prevent colorectal cancer?

Since colon polyps often remain asymptomatic for a long time, regular checkups are the best protection. Experts recommend a colonoscopy from the age of 50, and even earlier if there is a family history of polyps or other risk factors.

Those who shy away from the traditional approach or want an initial assessment can opt for modern tumor DNA stool tests . These can detect even small amounts of blood and genetic changes in intestinal cells – often at a very early stage.

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Colon cancer prevention - How can colon polyps and colon cancer be prevented?

In most cases , colorectal cancer develops from initially benign polyps. These small growths in the intestinal lining are common in many people – often remaining undetected for a long time because they cause no symptoms. Early detection is therefore crucial, as polyps can transform into malignant tumors over the course of years.

The most effective form of colorectal cancer prevention is regular participation in screening examinations. The combination of a healthy lifestyle, a balanced diet, exercise, and targeted screening can significantly reduce the risk of colorectal cancer. Paying attention to your body's signals and taking advantage of available medical services can make a crucial contribution to your own health.

Because the earlier changes in the intestine are detected, the better the chances of recovery – often even before cancer develops.

Frequently Asked Questions

Are colon polyps always a precursor to cancer?

No, not all colon polyps develop into cancer. Many remain benign. However, some types of polyps, such as adenomatous polyps, have a higher risk of malignant transformation and are considered potential precursors to colon cancer.

Is it possible to detect polyps without a colonoscopy?

Generally not. Polyps usually don't cause any symptoms. Stool tests can indicate the presence of blood or genetic changes, but a definitive diagnosis and removal are only possible via colonoscopy.

What role does genetics play in polyp formation?

Genetics can play a significant role. Familial predispositions, such as Lynch syndrome or familial adenomatous polyposis (FAP), increase the risk of developing polyps early and more frequently. Genetic counseling can be beneficial in such cases.

About the author

Dr. med. Annette Buhlmann

Specialist in laboratory diagnostics

With over 20 years of experience in managing medical diagnostic laboratories, Dr. Annette Buhlmann brings a wealth of knowledge in human genetics, molecular genetics and general medicine.

Learn more on the author's page