From the Guidelines
The recommended screening interval for computed tomography (CT) colonography for average-risk patients is every 5 years. This interval is appropriate for asymptomatic individuals aged 50 years and older who have no personal history of adenomatous polyps, colorectal cancer, inflammatory bowel disease, or family history of colorectal neoplasia. CT colonography is a less invasive alternative to traditional optical colonoscopy that uses low-dose radiation to create detailed 3D images of the colon and rectum. The 5-year interval is based on the natural history of colorectal polyp development and the high sensitivity of CT colonography for detecting clinically significant polyps (6 mm or larger) 1. If polyps are detected during CT colonography, patients will typically need to undergo a follow-up optical colonoscopy for polyp removal and may require more frequent surveillance based on the findings. Patients should be aware that CT colonography requires bowel preparation similar to conventional colonoscopy, and that the procedure involves radiation exposure, though at relatively low doses.
Some key points to consider when recommending CT colonography for average-risk patients include:
- The American College of Radiology (ACR) and the American Cancer Society (ACS) recommend CT colonography every 5 years for average-risk adults aged 50 years and older 1.
- The U.S. Multi-Society Task Force on Colorectal Cancer (MSTF) also recommends CT colonography every 5 years for average-risk adults aged 50 years and older 1.
- CT colonography has been shown to be effective in detecting clinically significant polyps and reducing the risk of colorectal cancer 1.
- However, CT colonography is not without risks, including radiation exposure and the potential for false-positive results, which can lead to unnecessary follow-up procedures 1.
Overall, the 5-year screening interval for CT colonography is a reasonable and evidence-based recommendation for average-risk patients, taking into account the benefits and risks of the procedure.
From the Research
CT Colonography Screening Interval
The recommended screening interval for computed tomography (CT) colonography for average-risk patients is not explicitly stated in the provided studies. However, the studies provide information on the effectiveness and recommendations for colorectal cancer screening.
- The US Preventive Services Task Force recommends screening for colorectal cancer starting at age 50 years and continuing until age 75 years 2.
- The U.S. Multi-Society Task Force on Colorectal Cancer suggests average-risk CRC screening begin at age 45 and recommends individualized decision-making for individuals ages 76 to 85 3.
- A study on CT colonography found that it is a sensitive and specific screening test for detecting polyps 10 mm or larger in average-risk patients 4.
- Another study discusses the growing interest in CT colonography as a screening option for colorectal cancer, but does not provide specific recommendations for screening intervals 5.
- A review of screening and diagnosis for colorectal cancer mentions the addition of CT colonography to the list of screening options, but does not provide information on recommended screening intervals 6.
Screening Recommendations
The studies provide the following recommendations for colorectal cancer screening:
- Screening for colorectal cancer is recommended for average-risk, asymptomatic adults aged 50 to 75 years 2.
- Average-risk CRC screening should begin at age 45 3.
- The decision to screen for colorectal cancer in adults aged 76 to 85 years should be individualized 2, 3.
- Screening is not recommended after age 85 3.