American College of Gastroenterology Updates Its CRC Screening Guidelines

March 2021 brought 21 updated recommendations and guidelines from the American College of Gastroenterology (ACG) regarding colorectal cancer (CRC) screening.

While the American Cancer Society recommends CRC screening for those aged 45 and up, the ACG recommends regular CRC screening for those aged 50-75, which follows the current recommendations set by the U.S. Preventive Services Task Force and the Multi-Speciality Task Force. For those aged 76 and beyond, the ACG recommends that the decision to screen for CRC be dependent on the health status and lifestyle of each individual, as the risks of CRC screening can outweigh the benefits depending on the individual’s situation. 

The recommendation to start screening at age 50 is only for those at average risk for CRC. For those who have a family history of CRC or advanced polyps and are therefore at a two-fold increased CRC risk, the ACG recommends screening starting at the age of 40 or 10 years before the youngest affected relative—whichever comes first. 

The various CRC screening options include:

• Stool-based tests like fecal immunochemical test (FIT) and multitarget stool DNA (mtsDNA)
• Blood-based tests like Septin 9
• Direct visualization like colonoscopy, flexible sigmoidoscopy, CT colonography, and colon capsule

The ACG recommends that colonoscopy and FIT should be the primary CRC screening methods. While advising against the Septin 9 blood test due to its low CRC detection sensitivity, the ACG does recommend the other screening methods outlined above for individuals who do not want to undergo a colonoscopy or FIT. It is important to note that all non-colonoscopy screening methods require a follow-up colonoscopy in the case of a positive result.  

In terms of chemopreventive methods, multiple long term studies have indicated that aspirin can reduce CRC incidence and mortality. However, these studies showed mixed results and did not break down the results by individual CRC screening history, so the ACG recommends against the usage of aspirin as a substitute for traditional CRC screening methods. 

Recommendations for Improving the Quality of Colonoscopy Screening 

Of all the screening methods, a direct visualization test like the colonoscopy is the most commonly performed procedure in the U.S. However, the colonoscopy does come with a main drawback: the results of the test are dependent upon the colonoscopist. The Adenoma Detection Rate (ADR), defined by “the fraction of persons aged 50+ who have one or more adenomas detected and removed,” is a good indicator of colonoscopy performance quality. Several studies have identified a link between colonoscopists with higher ADR rates and a reduction in CRC in their patients. Therefore, the ACG recommends remedial training for colonoscopists with an ADR of <25%.

The ACG further recommends that colonoscopists spend at least six minutes inspecting the mucosa before the scope is withdrawn from the anus, as a withdrawal time of six minutes or more increased the detection of neoplastic lesions and reduced the risk of post-colonoscopy CRC (PCCRC). An additional indicator of colonoscopy quality is the cecal intubation rate (CIR), which is defined as “the passage of the colonoscope tip into the cecal caput.” It is recommended that colonoscopists achieve a CIR of at least 95%, as studies have shown that a low CIR is associated with an increased risk of PCCRC.

Recommendations for Increasing Awareness About CRC Screening

As CRC remains the third leading cause of cancer in the U.S. among men and women, screening outreach is essential to increase participation in CRC screening. Studies have found that various screening outreach methods like brochures, invitations, reminders, patient navigation, patient reminders, clinical interventions, and clinical reminders were associated with increased CRC screening rates. Additionally, having primary care providers involved in screening outreach methods increased patient participation in CRC screenings. Therefore, the ACG recommends all the above to increase screening participation. 

To improve adherence to follow-up colonoscopies after positive non-colonoscopy results, the ACG recommends mail and phone reminders, patient navigation, and provider interventions.

The Colon Cancer Foundation implemented various campaigns this March to increase CRC screening participation in honor of National Colon Cancer Awareness Month. One of the most notable was the #GiveaCrapChallenge, where CCF partnered with Squatty Potty and DuClaw Brewing Company to screen 100 people for colon cancer. Participants traded a stool sample via a FIT kit for a limited edition, six-pack brew sample from DuClaw. These types of innovative screening outreach methods can increase participation in CRC screening, allowing for earlier detection of CRC.

Early detection can significantly reduce the incidence and mortality of CRC. Though there are currently no randomized clinical trials that compare the various CRC screening intervals in terms of the number of life-years gained, the Cancer Intervention and Surveillance Modeling Network, through various studies, recommends the following:

• Annual FIT
• Colonoscopy every 10 years
• mtsDNA test every 3 years
• Flexible sigmoidoscopy every 5-10 years
• CT colonography every 5 years
• Colon capsule every 5 years