The American College of Gastroenterology (ACG) now suggests that colorectal cancer screening begins at age 45 in average-risk people. Previously, the ACG recommended such early screening only for African Americans.
This conditional recommendation, based on low-quality evidence, accompanies the group’s strong and continued recommendation for screening people aged 50 to 75 years of average risk.
The new recommendation, an update to the group’s 2009 guidance, follows similar moves by the US Preventive Services Task Force in 2020 (draft recommendation) and the American Cancer Society in 2018.
The guideline authors note that the incidence of colorectal cancer is increasing in people under age 50 in the United States.
Summary Colorectal cancer (CRC) is the third most common cancer in men and women in the United States. CRC screening efforts are directed toward the removal of adenomas and sessile serrated lesions and the detection of early-stage CRC. The purpose of this article is to update the 2009 American College of Gastroenterology CRC screening guidelines. The guideline is framed by several key questions. We conducted a comprehensive literature search to include studies through October 2020. Inclusion criteria were studies of any design with men and women aged 40 years or older. Detailed recommendations for CRC screening in average-risk individuals and those with a family history of CRC are discussed. We also provide recommendations on the role of aspirin for chemoprevention, quality indicators for colonoscopy, approaches to organized CRC screening, and improving compliance with CRC screening. CRC screening must be optimized to allow for an effective and sustained reduction in CRC incidence and mortality. This can be achieved by achieving high rates of adherence, monitoring and quality improvement, following evidence-based guidelines, and removing barriers across the spectrum of care, from non-invasive screening to diagnostic and screening colonoscopy. The development of cost-effective, highly accurate, and non-invasive modalities associated with improved overall adherence to the screening process is also a desirable goal. |
Abbreviations: CRC: colorectal cancer. FIT: fecal immunochemical test.
The “ideal” screening test should be noninvasive, have high sensitivity and specificity, be safe, readily available, convenient, and affordable.
For the detection of CRC, there are multiple approved tests and strategies, each with its strengths and weaknesses. In some cases, the "best" screening test may be considered the one that is acceptable to the patient and is completed.
One approach to CRC screening is to divide it into 1-step (direct) testing (i.e., colonoscopy, which is diagnostic and therapeutic) or 2-step testing that requires a colonoscopy if positive, to complete the screening process. . All screening tests other than colonoscopy are 2-step tests.
A major limitation of non-colonoscopy-based CRC screening (eg, stool-based flexible sigmoidoscopy, CT colonography [CTC], or colon capsule [CC]) is that a positive test requires a follow-up colonoscopy . This 2-step testing approach represents a continuous screening process, requires strong systems-based support to complete the screening cascade, and is most effectively applied in organized screening (9).
In the United States, there are few select healthcare systems with scheduled and organized screening, and most screening is performed with a one-step opportunistic approach. Because the focus of the guideline is on providers practicing in the United States, the review highlights options for CRC screening currently in use, which primarily include colonoscopy and, in an organized setting, fecal immunochemical testing ( FIT).
Other 2-step tests, such as flexible sigmoidoscopy, multi-target stool DNA testing, CTC, and CC, are reserved for people who do not want or cannot have a colonoscopy or FIT, or those with a colonoscopy incomplete (CTC or CC). Comparative efficacy studies are lacking.
recommendations
- We recommend CRC screening in medium-risk individuals between the ages of 50 and 75 years to reduce the incidence of advanced adenoma, CRC, and CRC mortality. Strong recommendation; moderate quality evidence.
- We suggest CRC screening in average-risk individuals between the ages of 45 and 49 years to reduce the incidence of advanced adenoma, CRC, and CRC mortality. Conditional recommendation; very low quality evidence.
- We suggest that the decision to continue screening after age 75 be individualized. Conditional recommendation; very low quality evidence.
- We recommend colonoscopy and FIT as the primary screening modalities for CRC detection. Strong recommendation; low quality evidence.
- We suggest considering the following screening tests for people who cannot or do not want to undergo a colonoscopy or FIT: flexible sigmoidoscopy, multi-target stool DNA testing, CT colonography, or colon capsule. Conditional recommendation; very low quality evidence.
- We suggest against Septin 9 for CRC screening. Conditional recommendation, very low quality evidence.
- We recommend that the following intervals be followed for screening modalities: Fecal Immunochemical Test (FIT) every 1 year, Colonoscopy every 10 years. Strong recommendation; low quality evidence.
- We suggest that the following intervals be followed for screening modalities: Multi-target stool DNA testing every 3 years. Flexible sigmoidoscopy every 5 to 10 years CTC every 5 years, CC every 5 years. Conditional recommendation; very low quality evidence.
- We suggest starting CRC screening with a colonoscopy at age 40 or 10 years earlier than the youngest affected relative, whichever comes first, for people with CRC or advanced polyp in 1 first-degree relative (FDR) at age <60 years or advanced CRC or polyp at ≥2 FDR at any age. We suggest an interval colonoscopy every 5 years. Conditional recommendation; very low quality evidence.
- We suggest considering genetic evaluation with a greater burden of familial CRC (greater number and/or younger age of the affected family member). Conditional recommendation; very low quality evidence.
- We suggest starting CRC screening at age 40 or 10 years earlier than the youngest affected relative and then resuming average-risk screening recommendations for people with CRC or polyp advanced by 1 FDR at age ≥60 years. Conditional recommendation; very low quality evidence.
- In individuals with 1 second-degree relative (SDR) with CRC or advanced polyp, we suggest following average-risk CRC screening recommendations. Conditional recommendation; low quality evidence.
- We recommend that all endoscopists performing screening colonoscopy measure their individual cecal intubation rates (CIR), adenoma detection rates (RAM), and withdrawal times (WT). Strong recommendation, moderate quality evidence for ADR, low quality evidence for WT and CIR.
- We suggest that colonoscopists with ADRs below the minimum recommended thresholds (<25%) should undergo remedial training. Conditional recommendation, very low quality evidence.
- We recommend that colonoscopists spend at least 6 minutes inspecting the mucosa during removal. Strong recommendation, low quality evidence.
- We recommend that colonoscopists achieve a CIR of at least 95% in screening subjects. Strong recommendation, low quality evidence.
- We suggest low-dose aspirin in people ages 50 to 69 with a ≥10% risk of cardiovascular disease over the next 10 years, who are not at increased risk of bleeding, and are willing to take aspirin for at least 10 years to reduce risk. of CCR. Conditional recommendation; low quality evidence.
- We do not recommend the use of aspirin as a substitute for CRC testing. Strong recommendation, low quality evidence.
- We recommend organized screening programs to improve adherence to CRC screening compared to opportunistic screening. Strong recommendation; low quality evidence.
- We suggest the following strategies to improve screening compliance: patient navigation, patient reminders, physician interventions, provider recommendations, and clinical decision support tools. Conditional recommendation; very low quality evidence.
- We suggest the following strategies to improve adherence to follow-up of a positive screening test: mail and telephone reminders, patient navigation, and provider interventions. Conditional recommendation; very low quality evidence.
Conclusions Despite the availability of multiple screening modalities and several public health initiatives to boost CRC screening, nearly one-third of the eligible US population is not screened. CRC detection rates should be optimized to achieve the aspiration goal of >80%. Substantial reductions can be achieved by achieving high adherence rates and providing fail-safe systems to decrease barriers across the spectrum of care from a positive test without colonoscopy to a colonoscopy to complete the screening process. Recognizing the screening tools available for use in the correct settings for each population will increase compliance for different populations. Consistent with this goal, adoption of cost-effective, highly accurate, and non-invasive methodologies associated with reduced complications and barriers than more invasive methods may improve overall acceptance of the screening process. Fecal immunochemical testing (FIT) is a widely accepted, inexpensive, non-invasive 2-step CRC test and is optimal for programmatic screening and when systems are in place to guide patients toward colonoscopy. Colonoscopy is a 1-step CRC screening test, the final common route to a positive screening test without colonoscopy and the most appropriate screening test for people with a family history of CRC. The quality of CRC screening provision, by any method, must be monitored and improved to achieve reductions in CRC incidence and mortality. |
