Initiating regular screening at the recommended age and time interval is key to preventing and early diagnosis of colorectal cancer (CRC). An early CRC diagnosis improves survival. The American Cancer Society (2018) and the U.S. Preventive Services Task Force (2020) recommended that CRC screening should start at 45 instead of 50 years, in reaction to the growing incidence of CRC among younger people.
All major U.S. guidelines now endorse average-risk CRC screening at 45 years of age. However, there are concerns that endoscopic capacity may be strained, that low-risk persons may self-select for screening, and that calculations of the adenoma detection rate may be diluted.
A new study supports the recommendation that colonoscopies should start at age 45, not 50 years. In this study, researchers compared colonoscopy volumes and lesion detection rates in the U.S. healthcare system before (October 2017 to December 2018) and after (January 2019 to August 2021) the new guidelines were issued. They included 7,990 patients who had undergone colonoscopies from October 2017 through August 2021: 4,266 first-time colonoscopies and 3,724 re-screening colonoscopies.
Researchers found that:
- After the screening age for colonoscopy was lowered, younger people were more likely to undergo the procedure
- Among people ages 45 to 49, first-time screening rates increased from 3.5% in the period before guidelines were changed to 11.6% after they were updated
- First-time colonoscopies were still largely performed in patients ages 50 to 54 in both time periods, while re-screening colonoscopies showed a shifting trend toward older ages
- Patients ages 60 to 64 were the most likely to undergo re-screening during both time periods
They concluded that in our healthcare system in the early contemporary era of updated CRC screening guidelines, screening colonoscopy volume among 45- to 49-year-old patients has increased modestly, and lesion detection rates in 45- to 49-year-old patients have not decreased as might have been seen if low-risk persons were self-selecting for screening. The authors acknowledged that their findings were based on a single healthcare system and that national data will be important to assess the impact of the revised guidelines.
Kitty Chiu is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.