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October 22, 2021 07:14pm
By Ashley Gallagher, Assistant Editor
Screening for colorectal cancer (CRC) should begin at age 45 for people of average risk, according to newly updated American Cancer Society guidelines.
Screening for colorectal cancer (CRC) should begin at age 45 for people of average risk, according to newly updated American Cancer Society guidelines. The recommendation reflects a lowering of the starting age for individuals of average risk, from age 50, and is based on data that indicate increasing rates of CRC in young and middle-aged populations.
The recommendations were recently published in the ACS journalCA: A Cancer Journal for Clinicians. “One of the most significant and disturbing developments in CRC is the marked increase in CRC incidence—particularly rectal cancer—among younger individuals,” wrote the authors. “While the causes of this increase are not understood, it has been observed in all adult age groups below the age when screening has historically been offered, and is contributing significantly to the burden of suffering imposed by premature CRC mortality.
In a press release announcing the update, the ACS said there is an expectation that screening will be regularly performed in adults age 45-49 as it has been recommended for those aged 50 and older. The recommendations also suggest:
Most studies have only included adults aged 50 and older, according to the ACS. Therefore, the change reflects a ‘qualified recommendation,’ due to less direct evidence of the balance of benefits and harms, or patients’ values and preferences, related to CRC screening in adults aged 45-49. The recommendation for regular screening in adults aged 50 years and older is designated as a ‘strong recommendation,’ on the basis of the greater strength of the evidence, as well as the overall benefit.
Recommended options for colorectal cancer screening include: fecal immunochemical test (FIT) annually; high sensitivity guaiac-based fecal occult blood test (HSgFOBT) annually; multi-target stool DNA test (mt-sDNA) every 3 years; colonoscopy every 10 years; CT colonography (CTC) every 5 years; and flexible sigmoidoscopy (FS) every 5 years.
The new guideline does not prioritize among screening test options. Given the evidence that adults vary in their test preferences, the guidelines development committee emphasized that screening rates could be improved by endorsing the full range of tests without preference. The ACS has also developed new materials to facilitate conversations between clinicians and patients that would help patients decide which test is best for them.
CRC incidence has declined steadily over the past 2 decades in people aged 55 and older, due to screening that results in removal of polyps, as well as changes in exposure to risk factors. However, there has been a 51% increase in CRC among those under age 50 since 1994. Death rates in this age group have also begun to rise in recent years, indicating that increased incidence rates do not appear to be solely the result of increased use of colonoscopy. A recent analysis found that adults born around 1990 have twice the risk of colon cancer and 4 times the risk of rectal cancer compared with adults born around 1950, who have the lowest risk.
While the colorectal cancer incidence rate among adults aged 45 to 49 is lower than it is among adults aged 50 to 54 (31.4 vs. 58.4 per 100,000), the higher rate in the 50-54 age group is partially influenced by the uptake of screening at age 50, which leads to an increase in the incidence rate, due to detection of prevalent cancers before symptoms arise. Since adults in their 40s are far less likely to be screened than those in their 50s (17.8% vs. 45.3%), the true underlying risk in adults aged 45-49 years is likely closer to the risk in adults ages 50 to 54 than the most recent age-specific rates would suggest. Importantly, studies suggest the younger age cohorts will continue to carry the elevated risk forward with them as they age.