It is estimated that 1 in 10 people aged 50 and over have one or more polyps in the colon. A polyp is a benign growth that develops in the mucous membrane. In the vast majority of cases, a polyp always remains benign. Only a small portion turns into a malignant tumor over time and causes colon cancer. A polyp does not always have to cause complaints. However, sometimes it causes persistent abdominal pain, diarrhea, constipation and blood in the stool. Many of our organs are lined with mucous membrane on the inside. This mucous membrane has an important protective function. It captures pathogens, such as bacteria, viruses and fungi, and transports them to places where they can be rendered harmless. However, the mucous membrane is sometimes also a good breeding ground for the growth of unwanted cells. This is, for example, the case with polyps.
Source: Rsabbatini, Wikimedia Commons (CC BY-2.5)
A proliferation of mucous membrane cells
Polyps can in principle arise in any organ that is lined with mucous membrane on the inside. Preferred sites, however, are the colon, stomach and nasal cavity. Sometimes, for unknown reasons, a proliferation of mucous membrane cells occurs. A polyp may then be the result (see image). A polyp can look like a ball, a mushroom or a square knot and varies in size from a few millimeters to a few centimeters. In some people, many polyps develop at the same time. In the vast majority of cases, a polyp always remains benign. However, a certain type of polyp (adenoma) can contain ‘troubled’ cells and eventually develop into a malignant tumor.
Abdominal pain, diarrhea, constipation and blood in the stool
Many people have one or more polyps in the colon without knowing it. A polyp does not always cause complaints. However, if a polyp is larger and partially narrows the intestine, it can lead to persistent abdominal pain, constantly feeling like you have to go to the toilet, alternating constipation and diarrhea and unexplained weight loss. A polyp can also damage the intestinal mucosa and an underlying blood vessel, causing bleeding. You will then see this blood in your stool. With a polyp in the rectum – the last part of the large intestine, your stool is mixed with bright red blood. The higher the polyp is in the intestines, the darker the blood is.
The influence of eating habits and lifestyle
It is often not clear why a polyp has developed in the colon. Eating habits and lifestyle do seem to play a role in this. Polyps are more common in people who eat a lot of animal fats and (red) meat. Excessive alcohol consumption, little exercise and being overweight also increase the risk of developing intestinal polyps. If these factors are present for years, this can lead to intestinal polyps later in life (after the age of 50).
Hereditary disorders as a cause
Occasionally, a hereditary condition causes one or more polyps in the intestine. An example of this is Lynch syndrome , also called Hereditary Non-Polyposis Colorectal Carcinoma (HNPCC). Due to a hereditary defect in the genes, people who suffer from Lynch syndrome develop one polyp in the large intestine. This polyp almost always develops into colon cancer. The risk of other forms of cancer (especially uterine cancer) is also increased with this condition. Of the total number of people suffering from colon cancer, Lynch syndrome is the cause of approximately 5%.
Familial Adenomatous Polyposis (FAP) is a hereditary condition in which hundreds of polyps occur in the colon due to a change in the DNA. Polyposis means ‘many polyps’. The polyps in FAP often arise between the ages of 10 and 20 and almost always cause colon cancer over time. FAP is the cause in about 1% of people with colon cancer. Later in life, people with FAP can also develop polyps in the small intestine and stomach. However, because there are far fewer of them and because they only develop later, the risk of small intestine cancer and stomach cancer is much smaller.
In MutYH-associated Polyposis (MAP), dozens of polyps develop in the colon before the age of 50 due to a mutation in a certain gene (MutYH gene). The number of polyps is generally much lower than with the hereditary condition FAP. The risk of colon cancer, although greatly increased, is also lower than with FAP. People who suffer from MAP can also develop polyps in the stomach.
The Peutz-Jeghers Syndrome is a rare hereditary condition in which several slowly growing polyps develop, mainly in the small intestine. However, the polyps can also occur in the colon, stomach and nose. The number of polyps varies per person. People with Peutz-Jeghers syndrome have a greater risk of (colon) cancer. Tumors often initially develop in the small intestine. However, later in life, tumors also often occur in other places in the digestive tract, the uterus, the ovaries, the breast and the lungs. In addition to polyps, Peutz-Jeghers syndrome also causes many pigment spots to develop at a young age on the face, hands and soles of the feet.
Examination in the hospital
If you go to the doctor with persistent intestinal complaints, he or she will often refer you to the hospital for further examination. This is certainly the case when there is blood in the stool. Polyps in the colon can be detected using an endoscopy, a CT scan or X-ray examination.
The doctor will usually opt for an endoscopy , a visual examination of the large intestine. A thin, flexible tube, with a camera and a light attached to it, is inserted into your colon through your anus. The inside of your large intestine can be clearly seen on a screen.
The doctor may also opt for a CT scan to examine the colon for any abnormalities. This examination is called a CT colonography and is a special X-ray examination that uses a CT scan. In this way, a good picture of the inside of the colon can be obtained, without the need for an internal examination. However, if a biopsy must be taken (a piece of tissue from the intestine) or the polyp must be removed, an endoscopy will still have to be performed. Finally, it may be decided to
examine the colon by means of X-rays , a so-called X-colon. The colon is then first filled with a contrast agent and then with air. This makes any abnormalities in the colon visible on the X-rays.
Removing polyp and healthy lifestyle
Polyps in the colon are always removed. Very occasionally, a benign polyp can develop into a malignant tumor. Most polyps can be removed immediately through a visual examination. Very large or flat polyps or polyps that have grown into the intestinal wall usually need to be removed via intestinal surgery. Depending on the type of polyp, the number of polyps, your age and any hereditary factors or underlying diseases or conditions, it may be necessary to return regularly for check-ups after the removal of the polyp. There is a chance that new polyps will form again at some point.
A healthy lifestyle can help prevent the development of (new) polyps. Eating lots of fruit and vegetables appears to have a positive influence on the condition of your colon. With a fiber-rich diet, drinking plenty of water and regular exercise, you keep your stool soft and flexible. This reduces the risk of intestinal problems. It is better not to eat too much red meat (beef, pork, lamb and goat meat) and processed meat (preserved by smoke, salt or chemicals). These types of meat seem to increase the chance of developing a polyp. Finally, it is important to maintain a healthy body weight, stop smoking and drink alcohol in moderation.
Bowel cancer population survey
The population screening for colon cancer will be introduced in 2013. All Dutch people between the ages of 55 and 75 will then be called upon every two years to submit a stool sample. If there are traces of blood in the stool, further investigation will take place. The aim is to further reduce the number of cases of colon cancer with this population survey.
Persistent abdominal pain, diarrhea, constipation, weight loss and blood in the stool can occur with various conditions. Some of them are innocent. However, it is important, especially if you find blood in your stool, to go to the doctor with these complaints. Colon cancer is almost always caused by abnormal intestinal polyps. By having polyps removed in a timely manner you may be able to prevent a lot of misery.
- Blood in the stool: the most common causes