From the Guidelines
Colonoscopy screening should begin at age 40 for individuals with a family history of colorectal cancer or advanced polyps in a first-degree relative, and at age 45 for average-risk individuals, with repeat colonoscopies every 10 years if results are normal, as recommended by the most recent guidelines 1. When considering colonoscopy screening in Ontario, it's essential to assess individual risk factors to determine the appropriate screening schedule.
- For average-risk individuals, screening should begin at age 45, with repeat colonoscopies every 10 years if results are normal.
- Those with a family history of colorectal cancer or advanced polyps in a first-degree relative should start screening at age 40 or 10 years before the youngest case in the family, whichever comes first, and repeat every 5 years.
- Individuals with personal history of adenomatous polyps typically need follow-up colonoscopies at 3-5 year intervals depending on the number, size, and type of polyps found, as outlined in the guidelines 1.
- Patients with inflammatory bowel disease should begin screening 8-10 years after disease onset and continue every 1-2 years.
- Those with hereditary syndromes like Lynch syndrome should start screening at age 20-25 and repeat every 1-2 years, according to the recommendations 1. The guidelines emphasize the importance of individualized screening recommendations based on risk factors, and healthcare providers should discuss the benefits, limitations, and potential harm associated with screening for colorectal cancer with their patients, as noted in the study 1.
- The most recent guidelines from 2017 1 provide the most up-to-date recommendations for colonoscopy screening, superseding earlier guidelines from 2008 1 and 2010 1.
- By following these guidelines, individuals can reduce their risk of developing colorectal cancer and improve their overall quality of life.
From the Research
Colonoscopy Screening Schedule in Ontario
The recommended colonoscopy screening schedule for individuals with average to high risk of developing colon cancer in Ontario is as follows:
- For average-risk individuals, screening is recommended between 50 and 74 years of age, with a biennial guaiac-based fecal occult blood test (gFOBT) or colonoscopy every 10 years 2, 3, 4.
- For individuals at increased risk, such as those with a family history of colorectal cancer, colonoscopy is recommended, with the frequency depending on the level of risk 2, 3, 5.
- For high-risk individuals with a positive family history of colorectal cancer or advanced colorectal polyp, screening should begin at age 40, with colonoscopy every 5-10 years 3, 5.
Risk Factors and Screening Intervals
The risk factors for colorectal cancer and the recommended screening intervals are:
- Family history of colorectal cancer: colonoscopy every 5-10 years 3, 5.
- Advanced colorectal polyp: colonoscopy every 5-10 years 3.
- Inflammatory bowel disease: surveillance colonoscopy at 8 to 10 years after diagnosis, followed by subsequent surveillance at 1 to 2 yearly intervals 6.
Screening Modalities
The recommended screening modalities for colorectal cancer are:
- Colonoscopy: every 10 years for average-risk individuals and every 5-10 years for high-risk individuals 2, 3, 4.
- Fecal occult blood test (FOBT): biennially for average-risk individuals 2.
- Fecal immunochemical test (FIT): annually or biennially for average-risk individuals 4.
- Computed tomographic colonography (CTC): every 5 years for all individuals 3.