4 Signs Your Colon Polyps May Be Cancerous
Key takeaways:
Colon polyps are growths within the colon. Most polyps are not dangerous, but some can turn into colon cancer over time.
The best way to know if you have colon polyps is to have a colonoscopy. Preventive screening is particularly important because colon polyps often don’t cause symptoms.
Removal is the definitive treatment for colon polyps, and it can prevent you from developing colon cancer. In many cases, your provider can remove polyps during a colonoscopy.
Finding out you have a colon polyp can be a scary experience. Fortunately, most colon polyps are noncancerous (benign). But you shouldn't ignore them. If left untreated, some polyps can turn into cancer over time.
In most cases, a surgeon can find and remove colon polyps during a colonoscopy. Then a specialist can carefully inspect the polyp tissue to make sure there’s no cancer.
What is a colon polyp?
A polyp is an abnormal growth of tissue. It can occur anywhere within the gastrointestinal (or digestive) tract. Colon polyps are growths inside the lining of the colon. When they develop, polyps can grow to be different sizes and shapes.
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The shape or histology (how the tissue looks under a microscope) will determine the type of polyp you have. Your provider can assess the shape of the polyp at the time of removal. But the histology of the polyp isn't known until after a pathologist inspects the tissue. You’ll get the pathology results of your exam within 1 to 2 weeks of your colonoscopy.
What are the different types of polyps?
There are two major types of polyps based on shape: sessile and pedunculated. Sessile polyps are flat and grow along the inner lining of the colon wall. Pedunculated polyps grow on a short stalk, like a mushroom. This can cause these types of polyps to protrude inside the colon.
After examining the polyp under a microscope, the pathologist can further classify the polyp. Polyps may be one of the following:
Adenomatous: Adenomatous polyps, or adenomas, are growths that look much like normal colon tissue. But these polyps are precancerous and should be removed.
Hyperplastic: These polyps are benign growths and do not typically become cancerous.
What causes polyps in the colon?
Experts aren’t entirely sure what causes colon polyps to grow. But some people are at increased risk. Risk factors for colon polyps include:
Smoking
Heavier body weight
Heavy alcohol intake
High-fat diet (including lots of red meat)
Low-fiber intake
History of inflammatory bowel disease (IBD)
Genetics can also play a role in the growth of colon polyps. If you have a family history of colon polyps, be sure to visit your healthcare provider for a checkup.
What are the symptoms of colon polyps?
Most people with colon polyps have no symptoms and don’t know they have them. But if you have symptoms — like rectal bleeding, blood in your stools, or other bowel changes — you should see your provider.
What are the signs that polyps may be cancerous?
The only way to be sure that a colon polyp has cancer is to remove the polyp and look at it under a microscope. But a colonoscopy may show some signs that there may be cancer.
Here are the top four signs that your polyps may be cancerous.
1. Large size
The size of your polyp matters. The bigger the size of the polyp, the greater the chance there’s cancer hiding within the mass. This is especially true if they’re 1 cm in size or larger. But small polyps can also contain cancer. A microscopic exam is the definitive way to know if there’s cancer.
2. Fixed or depressed
Polyps that are fixed or depressed in the center may be an ominous sign. A fixed colon polyp is one that’s stuck to the lining of the colon and unable to move. It’s more likely to be malignant. A depressed polyp may also have an increased risk of a deeper cancer, even when it’s a smaller size. A fixed or depressed polyp may be difficult (or impossible) to remove during the colonoscopy.
3. Blockage of stool
If a polyp becomes too large, it can cause the colon to have a narrower passageway. This can lead to a blockage of stool. If you have polyps that prevent feces from passing, you may have symptoms of constipation.
4. Bleeding
If the outer lining of the polyp is very fragile, it may bleed. This may be a sign of a cancerous polyp. If you have a bleeding polyp, you’ll either have blood in your stools or tar-like, black stools.
How long does it take for polyps to turn into cancer?
Colon cancer grows quite slowly. Once a polyp develops within the colon, it can take up to 15 years for it to turn into cancer. For this reason, colon cancer is preventable. And once you completely remove the polyp, there’s no risk of it turning into cancer.
After removal, it’s very rare for a polyp to come back. But at least 30% of people develop new polyps. This is why it’s so important that you follow up using the timeline your healthcare provider sets.
If you have multiple polyps, your provider may suggest that you repeat the colonoscopy in 3 to 5 years. This will depend on the pathology of the polyps you had removed.
How do you treat colon polyps?
Removal is the definitive treatment for colon polyps. A colonoscopy is the best test for identifying colon polyps. In most cases, your provider can remove the polyps during the procedure.
If your polyps are big, your healthcare provider may recommend that you see a surgeon. It may be necessary to discuss polyp removal using a bigger and more invasive procedure.
What happens if you don’t treat polyps?
If you don’t remove your colon polyps in a timely manner, you run the risk of complications. Leaving the masses in place may give precancerous polyps time to turn into cancer. Other risks include bleeding polyps or large polyps that block your stool from passing.
How do you get checked for colon polyps?
In most cases, screening for colon polyps is like checking for colon cancer. The current guidelines recommend screening for people between the ages of 45 to 75 years old. This is if you have an average risk of developing colon cancer. If you have a higher risk for colon cancer, screening may happen sooner.
There are several options for screening techniques. Stool studies can check for bleeding that may be due to colon cancer or polyps. Tests can also treat and remove colon polyps or cancers. The most common screening methods include:
Stool-DNA (FIT-DNA): This test picks up blood or abnormal DNA that could be due to a large polyp or cancerous growth. You may do this screening every 3 years.
Fecal immunochemical (FIT) test: A FIT test uses antibodies to detect blood in the stool. It’s a yearly screening.
Fecal occult blood test: This test uses chemicals to detect blood in the stool. It’s usually done yearly.
Flexible sigmoidoscopy: This test uses a thin camera to look at the lower part of the colon and rectum. It’s performed every 5 to 10 years with a yearly stool test.
Colonoscopy: This looks at every part of the colon and rectum and is the gold standard for diagnosing colon polyps and colon cancer. It’s due every 10 years, or more often if necessary.
Your provider will help you figure out which test is best for you. Your medical history and risk factors will help to guide this decision.
The bottom line
While colon polyps can cause worry, most of the time they are benign and not dangerous. But some polyps do have the ability to become cancerous over time. They also rarely have symptoms. That’s why it is so important to have a colonoscopy if you meet the screening requirements. If you’re concerned you may be at risk for polyps, talk to your provider for further guidance.
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References
American Cancer Society. (2017). Understanding your pathology report: Colon polyps (sessile or traditional serrated adenomas).
American Cancer Society. (2020). American Cancer Society Guideline for colorectal cancer screening.
American Cancer Society. (2020). Can colorectal polyps and cancer be found early?
American Society for Gastrointestinal Endoscopy. (n.d.). Understanding polyps and their treatment.
American Society of Colon and Rectal Surgeons. (n.d.). Polyps of the colon and rectum.
Bujanda, L., et al. (2010). Malignant colorectal polyps. World Journal of Gastroenterology.
Centers for Disease Control and Prevention. (2022). Colorectal cancer screening tests.
Meseeha, M., et al. (2022). Colon polyps. StatPearls.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Symptoms and causes of colon polyps.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Treatment for colon polyps.
Shaukat, A., et al. (2020). Endoscopic recognition and management strategies for malignant colorectal polyps: Recommendations of the US Multi-Society Task Force on colorectal cancer. Gastroenterology.
Zeitz, M. P. (2010). Colon polyps. American College of Gastroenterology.
