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David Baxter PhD

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CRC Screening to Start at Age 45: ACG Update

Pam Harrison, Medscape
March 8, 2021

Colorectal cancer (CRC) screening is now recommended for average-risk individuals starting at age 45 years, according to the American College of Gastroenterology's (ACG's) updated guidelines.

The starting age was previously 50 years except for Blacks, for whom the starting age was lowered to 45 years in 2005.

The new guidance brings the ACG in line with recommendations of the American Cancer Society, which lowered the starting age to 45 years for average-risk individuals in 2018.

However, the US Preventive Services Task Force, the Multi-Specialty Task Force, and the American College of Physicians still recommend that CRC screening begin at the age of 50.

The new ACG guidelines were published in March in the American Journal of Gastroenterology. The last time they were updated was in 2009.

The ACG says the move was made in light of reports of an increase in the incidence of CRC in adults younger than 50.

"It has been estimated that [in the United States] persons born around 1990 have twice the risk of colon cancer and 4 times the risk of rectal cancer compared with those born around 1950," guideline author Aasma Shaukat, MD, MPH, University of Minnesota, Minneapolis, Minnesota, and colleagues point out.

"The fact that other developed countries are reporting similar increases in early-onset CRC and birth-cohort effects suggests that the Western lifestyle (especially exemplified by the obesity epidemic) is a significant contributor," the authors add.

The new ACG guidelines emphasize the importance of initiating CRC screening for average-risk patients aged 50 to 75 years.

Now, however, it suggests that the decision to continue screening after age 75 should be individualized. It notes that the benefits of screening are limited for those who are not expected to live for another 7 to 10 years. For patients with a family history of CRC, the guideline authors recommend initiating CRC screening at the age of 40 for patients with one or two first-degree relatives with either CRC or advanced colorectal polyps.

They also recommend screening colonoscopy over any other screening modality if the first-degree relative is younger than 60 or if two or more first-degree relatives of any age have CRC or advanced colorectal polyps. For such patients, screening should be repeated every 5 years.

For screening average-risk individuals, either colonoscopy or fecal immunochemical testing (FIT) is recommended. If colonoscopy is used, it should be repeated every 10 years. FIT should be conducted on an annual basis.

This is somewhat in contrast to recent changes proposed by the American Gastroenterological Association (AGA). The AGA recommends greater use of noninvasive testing, such as with fecal occult blood tests, initially. It recommends that initial colonoscopy be used only for patients at high risk for CRC.

For individuals unwilling or unable to undergo colonoscopy or FIT, the ACG suggests flexible sigmoidoscopy, multitarget stool DNA testing, CT colonography, or colon capsule. Only colonoscopy is a single-step test; all other screening modalities require a follow-up colonoscopy if test results are positive.

"We recommend against the use of aspirin as a substitute for CRC screening," ACG members emphasize. Rather, they suggest that the use of low-dose aspirin be considered only for patients aged 50 to 69 years whose risk for cardiovascular disease over the next 10 years is at least 10% and who are at low risk for bleeding.

To reduce their risk for CRC, patients need to take aspirin for at least 10 years, they point out.

Quality Indicators​

For endoscopists who perform colonoscopy, the ACG recommends that all operators determine their individual cecal intubation rates, adenoma detection rates, and withdrawal times. They also recommend that endoscopists spend at least 6 minutes inspecting the mucosa during withdrawal and achieve a cecal intubation rate of at least 95% for all patients screened.

The ACG recommends remedial training for any provider whose adenoma detection rate is less than 25%.

Screening Rates Dropped During Pandemic​

The authors of the new recommendations also point out that despite public health initiatives to boost CRC screening in the United States and the availability of multiple screening modalities, almost one third of individuals who are eligible for CRC screening do not undergo screening.

Moreover, the proportion of individuals not being screened has reportedly increased during the COVID-19 pandemic. In one report, claims data for colonoscopies dropped by 90% during April. "Colorectal cancer screening rates must be optimized to reach the aspirational target of >80%," the authors emphasize.

"A recommendation to be screened by a PCP [primary care provider] — who is known and trusted by the person — is clearly effective in raising participation," they add.

Shaukat has served as a scientific consultant for Iterative Scopes and Freenome. Other ACG guideline authors have relevant financial relationships, which are reported in the original publication.

Am J Gastroenterol. 2021;116:458-479. Full text
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