Overview of colonic polyps
A colonic polyp is a minor growth of tissue that projects from the lining of a section of the large intestine known as the colon. Colonic polyps, which are polyps in the colon or rectum, are estimated to occur in at least 30 percent of adults age 50 and older in the United States.
Colonic polyps also occur in children with an estimated 6 percent affected, increasing to 12 percent in those who experience intestinal bleeding. Most colon or intestinal polyps are harmless, but some can turn into cancer. If they do, it may take many years before they become cancerous.
Types of colonic polyps
A colonic polyp is a development that develops in the large intestine. Different types of polyps carry different risk factors. Also, the size of the polyp is related to its possible severity. The most mutual types of polyps are hyperplastic and adenomatous polyps:
Hyperplastic polyps: Hyperplastic polyps, or inflammatory polyps, are usually harmless and are not a cause for concern with a low potential for malignancy. These polyps will rarely become cancerous.
Adenomatous polyps: Adenomas, or adenomatous polyps, are not cancerous, but they can become cancerous in the future. Larger adenomas are more likely to become cancerous. Doctors often recommend the removal of adenomas.
Malignant polyps: Malignant polyps are contained cancer cells. The best treatment for these polyps will depend on the severity of cancer and the person’s general health.
Symptoms of colonic polyps
95% of colonic polyps cause no symptoms or signs and are discovered during screening or surveillance colonoscopy. When symptoms or signs do occur, they may include:
- Red blood mixed with or on the surface of the stool
- Black stools if the polyp bleeds a lot and is located in the proximal colon (cecum and ascending colon)
- Iron deficiency anemia if bleeding has been slow and has occurred for a long time.
- Weakness, lightheadedness, fainting, pale skin, and rapid heart rate due to iron deficiency anemia
- The presence of invisible (hidden) blood in the stool that is tested when screened for colon cancer at doctor’s office visits (due to the tendency of polyps to bleed slowly, intermittently, and in small amounts, fecal occult blood tests are often used to screen for colon cancer).
- Rarely diarrhea when great villous polyps secrete fluid into the intestine
- Infrequently constipation if the polyp is very large and obstructs the colon
- Rarely intussusception, a condition in which a polyp drags the portion of the colon to which it is attached toward the most distal colon (ie, it telescopes into the most distal colon) and leads to the obstacle of the colon. This can cause all the signs and symptoms of intestinal obstruction, including abdominal pain and bloating nausea, and vomiting.
Causes colonic polyps
Doctors do not know the exact cause of colonic polyps, but polyps are the result of abnormal tissue growth. The body periodically develops new healthy cells to replace old cells that are damaged or no longer needed. The growth and separation of new cells are usually regulated.
In some cases, however, the new cells grow and divide before they are needed. This overgrowth causes polyps to form. Polyps can grow in any area of the colon.
Risk factors of colonic polyps
Factors that can contribute to colonic polyps or cancer include:
- Years: Most people with colon polyps are 50 years or older.
- Inflammatory bowel conditions: Such as ulcerative colitis and Crohn’s disease.
- Family history: You are more likely to develop colonic polyps or cancer if you have a parent, brother, or child with them. If many family members have them, your risk is even higher. In some people, this connection is not inherited.
- Race: African Americans have a higher risk of developing colon cancer
- Consumption of tobacco and alcohol
- Obesity and lack of exercise
- Type 2 diabetes is not well controlled
Hereditary disorders that cause colonic polyps include:
Lynch syndrome: Lynch syndrome, also called hereditary nonpolyposis colorectal cancer. People with Lynch syndrome tend to grow relatively few polyps in the colon, but these polyps can quickly become malignant. Lynch syndrome is the most common form of inherited colon cancer and is also related to tumors in the breast, stomach, small intestine, urinary tract, and ovaries.
Familial adenomatous polyposis (FAP): A rare disorder that causes hundreds or even thousands of polyps to develop in the lining of the colon beginning in adolescence. If polyps are not preserved, your risk of developing colon cancer is nearly 100 percent, usually before age 40. Genetic testing can help determine your risk for FAP.
Gardner syndrome: A variant of FAP that reasons polyps to develop throughout the colon and small intestine. You can also develop non-cancerous tumors in other parts of your body, including your skin, bones, and abdomen.
MYH-associated polyposis (MAP): A condition similar to FAP caused by mutations in the MYH gene. People with MAP frequently develop multiple adenomatous polyps and colon cancer at a young age. Genetic testing can help determine your risk for MAP.
Peutz-Jeghers syndrome: A condition that usually begins with the development of freckles all over the body, including the lips, gums, and feet. Then, non-cancerous polyps develop throughout the intestines. These polyps can become malignant, so people with this condition are at increased risk for colon cancer.
Serrated polyposis syndrome: A condition that principals to multiple serrated adenomatous polyps in the upper part of the colon. These polyps can become malignant.
Diagnosis of colonic polyps
A doctor can discover colonic polyps in several different ways, including:
- Colonoscopy: A process in which a long, thin, flexible tube is placed through the rectum into the large intestine. The tube has a camera that displays images on a screen and removes polyps.
- Sigmoidoscopy: A thin, flexible tube is injected through the rectum to examine the last third of the large intestine (sigmoid colon).
- Computed Tomography (CT): A radiology test that uses radiation to create images of the large intestine.
- Stool tests: You provide the laboratory with a sample of stool, which will be tested for blood or genetic changes that suggest polyps and cancer. If the test is positive, a colonoscopy is required.
If any of the latter tests are abnormal, a colonoscopy should be performed to look for polyps and remove them.
Treatments for Colonic Polyps
Through a colonoscopy or flexible sigmoidoscopy, your physician uses forceps or a wire loop to remove polyps. This is called a polypectomy. If the polyp is too large to take out this way, you may need surgery to eliminate it. Once it’s out, a pathologist examines it for cancer.
If you have a genetic disorder like familial adenomatous polyposis, your doctor may mention surgery to remove part or all of your colon and rectum. That’s the best way to stop colon cancer for people with these health problems.
If you have colonic polyps, there’s a good plan you’ll get more of them later on. Your doctor will recommend that you have more screening tests later on.
Complications of colonic polyps
Some colonic polyps can become cancerous. The sooner polyps are removed, the less likely they are to become malignant.
Prevention of colonic polyps
You can greatly decrease your risk of colonic polyps and colorectal cancer by having regular screenings. Certain lifestyle changes can also help:
Adopt healthy habits. Include plenty of fruits, vegetables, and whole grains in your diet, and decrease your fat intake. Limit alcohol consumption and stop smoking. Stay physically active and keep healthy body weight.
Consider your choices if you are at high risk. If you have a family past of colonic polyps, consider genetic counseling. If you have been diagnosed with an inherited disorder that causes colonic polyps, you will need regular colonoscopies beginning in adulthood.