Colon polyps are small growths that form on the inner lining of the colon or rectum. Most are harmless, but some types can develop into colorectal cancer over time. Because they rarely cause symptoms, many people have them without knowing. That is why regular screening is one of the most important things you can do for your long-term health.
What Are Colon Polyps?
Colon polyps are extra tissue that grows along the wall of the large intestine. Doctors do not fully understand what causes them. However, certain lifestyle and genetic factors can raise your risk of developing them.
Most polyps are benign, meaning they are not cancerous. However, a type called an adenomatous polyp can turn into cancer if left untreated. Finding and removing these polyps early is the best way to prevent colorectal cancer. In fact, Health Canada recognizes colorectal cancer as one of the most preventable cancers through screening.
Common Symptoms of Colon Polyps
Most colon polyps cause no symptoms at all. This is what makes them tricky — you can feel perfectly healthy and still have polyps growing in your colon. As a result, routine screening becomes essential for early detection.
Symptoms tend to appear only when polyps grow larger than one centimetre or become cancerous. The most common sign is rectal bleeding, which means seeing blood in or on your stool. The stool may appear bright red or darker in colour depending on where the bleeding occurs.
Less Obvious Warning Signs
Sometimes the bleeding is not visible to the naked eye. This is called occult bleeding, and it can only be detected through a stool test. Your family doctor can order this simple test as part of a routine checkup.
Colon polyps do not usually cause pain or changes in bowel habits. However, if a large polyp partially blocks the colon, you might notice cramping, constipation, or diarrhea. These symptoms are rare because polyps are typically found and removed before they reach that size. Furthermore, once cancer develops, more serious symptoms like significant weight loss or a persistent change in bowel habits may appear.
Who Is at Higher Risk?
Anyone can develop colon polyps, but certain factors increase your chances. Knowing your risk level helps you and your doctor decide when to start screening and how often.
You may be at higher risk if you:
Are over the age of 50
Have a family history of colon polyps or colorectal cancer
Have had polyps or colorectal cancer before
Eat a diet high in fat and low in fibre
Smoke or drink alcohol regularly
Are overweight or physically inactive
Have an inflammatory bowel condition such as Crohn’s disease or ulcerative colitis
If a first-degree relative — such as a parent or sibling — was diagnosed with colorectal cancer before age 60, your doctor may recommend starting screening at age 40. Talk to your family doctor about your personal and family history to determine the right plan for you.
How Colon Polyps Are Diagnosed
The only reliable way to find colon polyps — especially small ones — is through a colon examination. Several tests are available, and your doctor will recommend the most appropriate one based on your age, risk level, and health history.
Stool-Based Tests
A fecal occult blood test (FOBT) checks for tiny amounts of blood in your stool that you cannot see. It is simple, low-cost, and non-invasive. You collect a small stool sample at home and send it to a lab. Research has shown that regular FOBT testing reduces deaths from colorectal cancer.
However, a negative result does not rule out cancer entirely. Therefore, if your result comes back positive, your doctor will refer you for a colonoscopy to investigate further. Many provincial health plans in Canada cover this test as part of routine screening.
Flexible Sigmoidoscopy
This procedure lets a doctor examine the lower third of the colon using a thin, flexible tube with a camera. The doctor can take tissue samples (biopsies) and remove precancerous growths during the same appointment. Studies show that when combined with an occult blood test, flexible sigmoidoscopy can detect up to 76% of advanced polyps and cancers.
It does not examine the full colon, so it may miss polyps in the upper sections. In addition, it is typically recommended every five years for average-risk adults.
Colonoscopy
A colonoscopy is the gold standard for detecting colon polyps. It allows the doctor to view the entire colon and rectum. Any suspicious tissue can be biopsied or removed on the spot, making it both a diagnostic and a treatment tool.
For people at average risk, a colonoscopy is recommended every 10 years starting at age 50. If you have a family history of colorectal cancer in a first-degree relative diagnosed before age 60, screening should start at age 40. After one or more polyps are removed, your doctor may recommend a follow-up colonoscopy every five years. According to the Mayo Clinic’s overview of colon polyps, colonoscopy detects approximately 95% of precancerous adenomatous polyps larger than one centimetre.
Double-Contrast Barium Enema
This is an X-ray examination of the large intestine. A liquid called barium is introduced into the colon to make growths more visible on the X-ray. It can detect polyps throughout the entire colon and is more accurate than a stool test alone.
However, it is less reliable than colonoscopy. It detects about 83% of precancerous polyps larger than one centimetre, compared to 95% for colonoscopy. Furthermore, it cannot be used to take biopsies or remove polyps, so a colonoscopy is still needed if anything suspicious is found.
Virtual Colonoscopy
Researchers are also exploring less invasive options. A virtual colonoscopy uses a CT scan to create detailed images of the colon without inserting a scope. It is a promising non-invasive screening method. However, if polyps are found, a traditional colonoscopy is still required to remove them. Genetic testing is another area under active research for early colorectal cancer detection.
Colorectal Cancer Screening Guidelines in Canada
Screening for colon polyps and colorectal cancer saves lives. Canadian health experts recommend that all adults aged 50 and over with average risk get screened regularly. You are considered average risk if you have no personal or family history of colon polyps or colorectal cancer, and no current symptoms.
Recommended screening options for average-risk adults include:
Fecal occult blood test (FOBT) — every one to two years
Flexible sigmoidoscopy — every five years
FOBT combined with flexible sigmoidoscopy — every five years
Double-contrast barium enema — every five years
Colonoscopy — every ten years
If you are at higher risk, your doctor may recommend starting earlier or screening more frequently. For example, people aged 20 to 25 with a known family history of hereditary colorectal cancer syndrome may need a colonoscopy every one to two years. Most provincial health plans cover at least one form of colorectal screening. Check with your province’s health programme to find out what is available to you. You can also learn more through Healthline’s guide to colon polyps and screening.
When to See a Doctor
You should speak to your family doctor if you notice any blood in your stool, even if it seems minor. Blood in the stool is never something to ignore. Your doctor can order a stool test or refer you to a specialist for further investigation.
If you do not have a family doctor, a walk-in clinic can help get the process started. Many walk-in clinics in Canada can order a fecal occult blood test and refer you for a colonoscopy if needed. Do not wait for symptoms to appear — most colon polyps cause no warning signs at all.
If you are 50 or older and have not had a colorectal screening yet, now is the time to bring it up at your next appointment. Early detection of colon polyps is the single best way to prevent colorectal cancer from developing.
Always speak with a qualified healthcare provider before making decisions about your screening schedule or health concerns. This article is for informational purposes only and does not replace professional medical advice.
Frequently Asked Questions About Colon Polyps
Are colon polyps dangerous?
Most colon polyps are benign and pose no immediate danger. However, a type called adenomatous polyps can develop into colorectal cancer if they are not found and removed. Regular screening is the most effective way to catch and remove colon polyps before they become a serious problem.
What causes colon polyps to form?
The exact cause of colon polyps is not fully understood. Risk factors include age, a diet low in fibre and high in fat, smoking, obesity, and a family history of polyps or colorectal cancer. Some people also have genetic conditions that make them more likely to develop polyps at a younger age.
How are colon polyps removed?
Colon polyps are most commonly removed during a colonoscopy in a procedure called a polypectomy. The doctor uses small tools passed through the colonoscope to cut away the polyp. This is usually done at the same time as the screening, with no need for a separate surgery.
At what age should Canadians start screening for colon polyps?
Most Canadian health guidelines recommend starting colorectal screening at age 50 for adults at average risk. If you have a family history of colon polyps or colorectal cancer, your doctor may suggest starting at age 40 or even earlier. Talk to your family doctor about your personal risk to determine the right starting age for you.
Can colon polyps come back after removal?
Yes, colon polyps can return after being removed. That is why follow-up colonoscopies are recommended, typically every five years after one or more polyps have been found and removed. Maintaining a healthy diet, staying active, and not smoking can help reduce your risk of new polyps forming.
Is a colonoscopy covered by provincial health plans in Canada?
In most Canadian provinces, a colonoscopy is covered under the provincial health plan when it is medically necessary or recommended by a doctor. Coverage for routine screening may vary depending on your province and your individual risk level. Contact your provincial health programme or speak with your family doctor to confirm what is covered in your area.
Key Takeaways
Colon polyps are growths in the colon or rectum that usually cause no symptoms.
Some polyps, particularly adenomatous ones, can develop into colorectal cancer if not removed.
The most common symptom is blood in the stool, which should always be assessed by a doctor.
Screening options include fecal occult blood tests, flexible sigmoidoscopy, and colonoscopy.
Canadians at average risk should start colorectal screening at age 50; those at higher risk may need to start earlier.
Most provincial health plans cover at least one form of colorectal cancer screening.
Regular screening and early removal of polyps is the most effective way to prevent colorectal cancer.
Speak with your family doctor or visit a walk-in clinic to discuss the right screening plan for you.
