When Should I Get A Colonoscopy?

(By Pei En Kwok, MD)

What is a Colonoscopy?
Colonoscopy  is a screening test used to look at the lining of your large intestines (colon) and rectum. A long flexible tube with a tiny video camera at the tip allows the doctor to visualize the inside of the colon and rectum. Sometimes if necessary, it can even be used to remove polyps and sample tissues from your colon.

Colonoscopy is the gold standard for colorectal cancer screening. With timely and appropriate screening, we are able to detect and prevent the occurrence of cancer.

Your First Colonoscopy.
The American Cancer Society recommends that people of average risk of colon cancer begin screening at 45 years old. If you remain in good health and do not have risk factors predisposing you to colon cancer, this will be done every 10 years until you are 75 years old.

After every colonoscopy, your doctor will review the results with you. For an average risk patient, the results of your colonoscopy will determine the timing of your next surveillance colonoscopy.

Negative Results
If there are no abnormalities found in the colon during a colonoscopy, it is considered negative.

In 10 years, if you are at average risk of colon cancer or if you have benign lesions (1-2 small adenomas or hyperplastic polyps).

In 1-7 years, depending on your personal risk factors: type, size and number of polyps (if any); your family history of colon cancer; your history of polyps in previous colonoscopies, if you have certain genetic syndromes or inflammatory bowel diseases.

Positive Results
Polyps are growths or protuberances into the lumen above colon mucosal lining. If polyps or abnormal tissues are found in the colon, it is considered positive. Most polyps are in and of themselves not cancerous, but some harbor the potential to evolve and can become precancerous. Once removed, these polyps will be sent to the pathology lab for analysis to determine if they are cancerous or not. You may need a colonoscopy sooner if you are found to have:

• sessile polyps (flat or dome shaped)
• more than 3 polyps
• large polyps (more than 1 cm/ 0.4 inches)
• incomplete removal of polyps
• cancerous polyps

Sometimes, if the quality of the bowel prep for your colonoscopy is not adequate, this can affect the quality of the view through the scope. Your doctor may recommend a repeat colonoscopy or a shorter time until your next colonoscopy.

People at High Risk of Colon Cancer

Personal or Family History
If you have an immediate family member (parent or sibling) with colorectal cancer, you should start screening at the age of 40 years old or 10 years before the youngest age at which your family member was diagnosed. You should have a screening colonoscopy every 5 years even with negative colonoscopy results.

Inflammatory Bowel Disease
Patients with IBD are 6 times more likely to develop colon cancer than the general population. If you were diagnosed with Crohn’s disease or Ulcerative Colitis, screening colonoscopy should start 8 years after diagnosis. This should be done every 1 to 3 years depending on the results of your previous colonoscopy and your personal risk factors.

Genetic Syndromes
There are several types of familial/ genetic syndromes associated with colorectal cancer. For example - familial adenomatous polyposis (FAP) or Lynch syndrome. If you were diagnosed with FAP, colonoscopy starts as young as at the age of 10-12 years old. If you were diagnosed with Lynch syndrome, colonoscopy should be done every 1-2 years starting at 20-25 years old. Genetic counseling and testing are proven to be beneficial as well. Specifics on each screening routine depends on which genetic syndrome you have and other health factors.

Talk to your healthcare provider to learn more about colorectal cancer screening. Your provider will determine the best personalized screening option and surveillance schedule for you.

Hear more about Colorectal Cancer from our Rectal Cancer Team: