Brief overview: Intestinal polyps
- What are intestinal polyps? Mucosal growths that protrude into the intestine.
- Are intestinal polyps dangerous? In principle no, but there is a risk of degeneration into colorectal cancer.
- Frequency: One third of all people over 60 years of age have intestinal polyps.
- Symptoms: Very rare, mostly incidental finding during colonoscopy, possibly mucous or bloody stool, possibly stool changes.
- Diagnosis: Usually by means of colonoscopy
- Treatment: Removal of intestinal polyps (polypectomy), usually during colonoscopy
Intestinal polyps: What are intestinal polyps?
Intestinal polyps are mucosal structures that protrude into the cavity of the intestine. They may sit flat on the intestinal mucosa, be connected to it by a style, or take on a “shaggy” shape.
Polyps are very common in the colon and rectum. They can be made of different tissues. Most often, they arise from glandular tissue of the intestinal mucosa. In this case, the intestinal polyps are called adenomas. Adenomas are benign structures, but they can turn into malignant cancerous tissue.
About 70 percent of intestinal polyps are adenomas!
Types of intestinal polyps
Doctors distinguish between intestinal polyps that often form anew in the intestine without any apparent cause (neoplastic intestinal polyps such as an adenoma) and polyps that are caused, for example, by inflammation (non-neoplastic intestinal polyps). The latter also include hamartomatous polyps. They arise from scattered germ cells and are usually congenital intestinal polyps.
If the upper mucosal cells multiply, doctors also speak of hyperplastic intestinal polyps. They are usually small. Adenomas are typically larger. If intestinal polyps develop from fat tissue cells, they are called lipomas. Under certain circumstances, a polyp may already be degenerated – in which case it is colon cancer.
Intestinal polyps: Symptoms
Many people ask themselves the following questions: How do I notice intestinal polyps? Are there any special symptoms? Polyps in the intestine usually do not cause any symptoms. Instead, doctors discover them by chance during a colonoscopy.
Take advantage of cancer screening! Colorectal polyps usually remain asymptomatic, but in many cases increase the risk of colorectal cancer!
Blood in the stool
Altered bowel movements
Under certain circumstances, affected persons also have mucous stools. Diarrhea and abdominal cramps are also possible symptoms in isolated cases. In a few cases, intestinal polyps cause constipation.
Intestinal polyps: Causes and risk factors
Intestinal polyps are much more common in the Western world than in Asian countries, for example. Therefore, it is believed that the Western lifestyle promotes the development of intestinal polyps. This includes high-fat and high-sugar foods, alcohol consumption and nicotine.
Lack of exercise is also likely to play a role in the development of colon polyps. Furthermore, genetic factors have a major influence.
Development of intestinal polyps
The mucous membrane of the colon renews itself regularly. In the process, old mucosal cells are broken down and new cells multiply. They then form the new mucosa. This is a continuous process.
During reproduction, small errors (mutations) can occur in the genetic material. Natural repair mechanisms of the body usually correct these errors. Now and then, however, certain mutations alter the growth characteristics of the mucosal cells.
Colorectal polyps: Genetic factors
Sometimes the tendency to form polyps in the intestine can be inherited. Doctors distinguish a genetic predisposition without a detectable cause from actual hereditary diseases. In this case, intestinal polyps grow much earlier in life. The risk of developing colorectal cancer is also increased.
Intestinal polyps in familial adenomatous polyposis (FAP)
In rare familial adenomatous polyposis (FAP), polyps grow from glandular tissue throughout the intestine (adenomatous intestinal polyps). A hereditary genetic mutation is the cause. In some cases, however, the mutations occur newly.
Affected individuals usually have some intestinal polyps in their teens. In FAP, however, there are often polyps elsewhere, such as in the stomach. Complaints are rather rare. Then abdominal pain, diarrhea, weight loss, flatulence or bloody-mucous stools are possible.
If left untreated, they almost always develop into colon cancer. People who have relatives with this condition should have their bowels checked regularly. In addition, relatives should get tested for FAP as part of genetic counseling.
Experts recommend that people with suspected FAP have an annual recto-sigmoidoscopy (“small” colonoscopy) from the age of ten!
In FAP, irregular tooth structures or changes in retinal pigmentation in the eye also occur. If affected individuals have tumors in bones (such as osteomas) and other tissues (e.g. epidermoid cysts), physicians refer to this as Gardner syndrome, a special form of FAP.
The risk of developing thyroid cancer is also slightly increased. In addition to intestinal polyps, about 80 percent of FAP patients also have thyroid nodules. Growths in the liver are also possible.
MUTYH-associated polyposis (MAP).
In MUTYH-associated polyposis (MAP), an inherited genetic defect is also the cause of early and frequent colon polyps. However, the disease is milder than FAP, fewer polyps develop, and they develop later in life.
The genetic defect is inherited in an autosomal recessive manner. This means parents can carry the mutated gene without being sick. If the father and mother each pass on a mutated gene, there is a risk that the offspring will develop the disease. Affected individuals have an 80 to 100 percent risk of developing colorectal cancer once in their lifetime.
Cronkhite-Canada syndrome
In the rare Cronkhite-Canada syndrome, intestinal polyps occur throughout the gastrointestinal tract. Brownish spots also appear on the skin. Finger and toenails may change in structure, and the hair on the head may fall out.
There is no specific treatment for Cronkhite-Canada syndrome. However, it sometimes responds to defense-suppressive therapy (immunosuppression).
Birt-Hogg-Dube syndrome
In Birt-Hogg-Dube syndrome, numerous intestinal polyps occur in the colon, which can very often develop into colon cancer. Additionally, tumors of the skin, kidneys, and lungs occur.
Hamartomatous polyposis syndromes
A hamartomatous syndrome can present with tumors in almost any part of the body. They arise from scattered germinal tissue. These are cells from embryonic development. These cells are not structured like the normal intestinal mucosa.
If intestinal polyps occur as part of such a syndrome, the risk of colorectal cancer is increased. In most cases, the disease occurs at a young age. Examples of hamartomatous intestinal polyps are:
- Peutz-Jeghers syndrome: diagnosed around age 35; polyps often found in the small intestine; risk of colorectal cancer about 40 percent, increased risk of pancreatic cancer, breast cancer, or ovarian cancer; often pigmentary abnormalities in the mouth area
- Familial juvenile polyposis: familial clustering in about one third; risk of colorectal cancer about 20-70 percent
Examinations and diagnosis
The first point of contact, for example, in the event of bowel movement problems, is the family doctor. He usually also schedules colorectal cancer screening. For this, he or she will refer you to a gastrointestinal specialist (gastroenterologist).
Taking your medical history (anamnesis)
The doctor first asks a few questions to get clues about his patient’s intestinal health:
- Do you suffer or have suffered from constipation, diarrhea, or irregular bowel movements?
- Have you noticed that your stool is bloody or mucousy?
- Is there any intestinal disease in your family?
- Have you lost weight unintentionally in recent weeks or months?
Physical examination
This is followed by the physical examination. Using a stethoscope, the doctor can listen to bowel sounds. Then he or she palpates the abdomen for possible indurations. An ultrasound machine can sometimes be used to visualize intestinal polyps in the rectum.
The doctor can also palpate intestinal polyps in the rectum. To do this, he inserts a finger into the anus. This so-called digital rectal examination (DRU) is also common for prostate cancer screening in men. The doctor may also find signs of bleeding through bloody stool residue on the glove.
Colonoscopy
Pathologists then examine the tissue. In doing so, they identify exactly which intestinal polyp is present. Adenomas can be divided into three subtypes. Depending on the type, the risk of the intestinal polyp developing into cancer varies:
- Tubular adenoma: most common form (60-65 percent), tubular growth, in the reflection one sees the intestinal polyps as hanging on a stalk on the intestinal wall, degeneration risk about four percent
- Villous adenoma: relatively rare (5-10 percent), broad-surfaced, looking like a lawn on examination, about half of these intestinal polyps degenerate into colorectal cancer
- Tubulovillous adenoma: about 20-25 percent of adenomas, mixed form of tubular and villous intestinal polyps
Abdominal CT/ MRI
If a colonoscopy is not possible, doctors can resort to a virtual colonoscopy. In this case, they take cross-sectional images using computed tomography (CT) or magnetic resonance imaging (MRI). However, usually only colon polyps larger than one centimeter can be seen.
Video capsule endoscopy
Prevention
Colon polyps and colon cancer are not rare diseases. For everyone in Germany, health insurance companies pay for preventive examinations after a certain age:
- From age 50: annual stool test for hidden (occult) blood (immunological stool test (iFOBT)
- Men over 50, women over 55: colonoscopy every ten years, in case of abnormalities the interval to the next colonoscopy is shortened
- If colonoscopy is refused: every five years small colonoscopy only up to the S-shaped bowel section and annual stool tests for occult blood
If colon polyps accumulate in the family, physicians recommend colonoscopy more frequently and earlier. Exactly how often depends on the type of hereditary colon polyp or colon cancer.
If first-degree relatives (children, parents or siblings) have an adenoma before the age of 50, those affected should have a colonoscopy ten years before the age at which the intestinal polyp appeared in the relative.
Talk to your relatives! This is the only way to better assess the risk of colorectal polyps and ultimately colorectal cancer!
If you subsequently suspect a family history or even a hereditary disease, talk to a trusted physician about it. He or she can refer you to specialists. Sometimes a visit to a genetic counseling service is also advisable.
Treatment
Since an intestinal polyp can turn into cancer, the doctor removes it – usually in the course of a colonoscopy (polypectomy). How exactly he removes the intestinal polyp ultimately depends on its size:
The doctor usually removes intestinal polyps smaller than five millimeters using biopsy forceps. For larger intestinal polyps, he uses an electric snare.
If the intestinal polyps sit broadly on the mucosa, snare removal is hardly possible. Then the doctor performs a colonoscopy with a small operation (transanal endoscopic microsurgery, TEM).
Large polyps sometimes need to be removed with surgery through the abdominal wall. In rare cases, surgeons remove a whole one. People who have genetic polyposis and are at very high risk for colorectal cancer sometimes have colon surgery as a precaution.
Course of the disease and prognosis
A polyp is actually a benign intestinal tumor. However, if it persists for a long time, it can develop into colon cancer. On average, it takes five to ten years for an adenoma to develop into colorectal cancer (adenoma-carcinoma sequence).
The larger the colon polyps are, the greater the risk of colorectal cancer.
Tips for colorectal polyps
- Exercise: Regular physical activity helps to keep your body fit. It also helps prevent intestinal polyps and intestinal cancer.
- Preventive care: You should also take advantage of the preventive examinations offered. Health insurance companies cover the costs at certain intervals. Ideally, you should contact your family doctor for this.
- Control: If the doctor has removed intestinal polyps, you should ideally follow the advice of your attending physician. If necessary, he or she will recommend that you have a check-up colonoscopy earlier than after the usual ten years.
- Pre-existing conditions: Pay special attention if your family has a history of colorectal polyps. Many intestinal polyps, but also chronic inflammatory bowel diseases such as ulcerative colitis or other malignant tumor diseases in the family ultimately also increase your risk of colorectal cancer.
