Colon and rectal polyps are small clumps of cells that can form on the lining of the rectum or the colon (AKA the large intestine). Polyps are usually either flat (AKA sessile polyps) or look like mushrooms with a short stalk (AKA pedunculated polyps). Polyps can vary in size from a quarter inch to several inches in diameter.
Most colorectal polyps are benign growths, meaning they do not impact the function of the colon or a person’s health and are unlikely to lead to colorectal cancer. However, some types of polyps can develop into colon cancer if not discovered early and removed.
Polyps — even those that may develop into cancer — usually don’t cause noticeable symptoms, which means many people who have colon polyps aren’t aware they have them. That’s why it’s important to have regular colon cancer screenings after age 45, especially if you’re in a group with increased risk factors for developing polyps or have a family history of colon cancer.
Polyps are rare in young people, but become much more common with age. According to the American Society for Gastrointestinal Endoscopy, more than 40% of people over age 50 have precancerous polyps in their colon.
There are several colon polyps types, including:
Hyperplastic polyps, which are usually small and rarely become cancerous
Adenomatous polyps, which are growths of glandular tissue cells that can potentially become cancerous if not removed. Around 70% of polyps are adenomatous
Sessile Serrated polyps, which are rarer than other types of polyps and may become cancerous if not treated
Villous Adenoma account for about 15% of polyps found during colon cancer screenings, and have a high risk of becoming cancerous.
Inflammatory polyps (AKA pseudopolyps) are usually found in patients with inflammatory bowel disease (IBD). Not considered true polyps, they are created by the body’s reaction to chronic inflammation of the bowel
Most colon polyps don’t cause noticeable symptoms, which means people may not know they have polyps unless they are discovered during a screening. However, in certain cases, patients may experience symptoms related to polyps. These symptoms may include:
Chronic constipation or diarrhea
Having stools that are tarry, black or include visible blood, which may indicate bleeding in your colon
Anemia or iron deficiency caused by internal bleeding
Chronic fatigue
Abdominal pain due to a blockage caused by a large polyp
In the U.S., polyps are common in adults. According to the National Institutes of Health, it’s estimated that between 15 and 40 percent of adults have colorectal polyps, with polyps more commonly seen in men than women. However, because polyps generally produce few noticeable symptoms, many of those with polyps may not know they have them. A small percentage of colon polyps develop into colorectal cancer, which makes screening for polyps and colorectal cancer after age 45 especially important.
Most polyps found during screenings are benign, meaning they probably won’t become colorectal cancer. However, certain types are considered “precancerous polyps.” Those who have them have a higher risk of developing colon cancer.
Hyperplastic polyps are generally not considered precancerous. However, doctors usually remove hyperplastic polyps when they find them during colon cancer screenings to reduce the risk to patients as much as possible.
Villous Adenoma account for about 15% of polyps found during colon cancer screenings, and have a high risk of becoming cancerous.
Adenomas are the most common type of precancerous colon polyp discovered during colorectal cancer screenings. It’s believed that only about 5% of adenomas eventually develop into colorectal cancer, but there’s currently no test to determine which polyps will. For the adenomas that do become cancerous, how fast they develop into cancer depends on the patient. An adenomatous colon polyp can take up to 7 years or more to go from pre-cancerous to cancerous.
Sessile serrated polyps are another potentially pre-cancerous type of colon polyp. These polyps are slightly flattened, and have a saw-toothed appearance when seen under the microscope (which is why they’re called “serrated”). While potentially dangerous, they are much less likely to become cancerous than adenomas.
It’s unclear why some people develop colon polyps while others of similar age, diet and habits don’t. Currently, there’s no known way to definitely prevent colon polyps. However, there are certain factors that are believed to increase your risk of having colon polyps. These may include:
Being older than 45
Being overweight or obese
Having diabetes
A personal or family history of polyps
A family history of colon cancer
Smoking and other forms of tobacco use
Having certain medical conditions that impact the colon, including ulcerative colitis or Crohn’s disease
Having certain inherited disorders, including Familial adenomatous polyposis (FAP), Gardner syndrome, Juvenile polyposis, Lynch syndrome and Peutz-Jeghers syndrome
Colon polyps are usually found during screening tests for colon cancer. The tests to detect polyps include:
Colonoscopy, which is a visual examination of the colon and rectum to look for (and often remove) polyps. During a colonoscopy — which is usually performed while the patient is sedated — a long, flexible camera called a colonoscope is inserted through the rectum and guided through the colon, allowing physicians to see the entire lining of the colon and check it for polyps. If any smaller polyps are found, they can usually be removed during the colonoscopy
Sigmoidoscopy, which is an exam similar to a colonoscopy that only looks at the sigmoid colon, which is the part of the colon closest to the rectum and anus
Fecal immunochemical tests (FIT), which are newer, non-invasive screening tests that are performed through patient-submitted stool samples. These samples are then examined for the presence of hidden blood, which may be related to colon cancer.
Most polyps, including those that can eventually develop into colorectal cancer, produce no noticeable symptoms that might alert you that you to see a doctor. Given that, regular screening for polyps and colon cancer is essential to detect colon polyps before they can become cancerous. According to the Centers for Disease Control and the U.S. Preventative Services Task Force, all Americans should begin colorectal cancer screening at age 45 and continue regular screening through age 75. Adults age 75-85 should talk to their doctor about how frequently they should be screened.
The most common treatment for colorectal polyps is immediately removing them. Polyp removal can often be done during a colonoscopy in which polyps are discovered if the polyps are small. If a patent is found to have adenomatous polyps — the type of colonic polyps that are most at risk to develop into colorectal cancer — new polyps are likely to appear in the future, so regular screenings every few years are often recommended. In rare cases in which polyps discovered during a colonoscopy are considered very likely to turn into cancer or are too large to be removed during the procedure, the physician may recommend a colectomy, which is surgery to remove part of the colon that has polyps.
There’s no known way to definitely prevent yourself from developing colon polyps. However, there are certain lifestyle changes you can take that are believed to reduce your risk of developing polyps and colon cancer. These include:
Eat a diet low in fat and high in fruits, vegetables and fiber
Quit smoking or using tobacco
Don’t drinking alcohol in excess
Get regular exercise and take steps needed to maintain a healthy body weight
Get routine colon cancer screening beginning at age 45