Colorectal cancer screening for average‐risk adults: 2018 guideline update from the American Cancer Society

Abstract

In the United States, colorectal cancer (CRC) is the fourth most common cancer diagnosed among adults and the second leading cause of death from cancer. For this guideline update, the American Cancer Society (ACS) used an existing systematic evidence review of the CRC screening literature and microsimulation modeling analyses, including a new evaluation of the age to begin screening by race and sex and additional modeling that incorporates changes in US CRC incidence. Screening with any one of multiple options is associated with a significant reduction in CRC incidence through the detection and removal of adenomatous polyps and other precancerous lesions and with a reduction in mortality through incidence reduction and early detection of CRC. Results from modeling analyses identified efficient and model-recommendable strategies that started screening at age 45 years. The ACS Guideline Development Group applied the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria in developing and rating the recommendations. The ACS recommends that adults aged 45 years and older with an average risk of CRC undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) examination, depending on patient preference and test availability. As a part of the screening process, all positive results on noncolonoscopy screening tests should be followed up with timely colonoscopy. The recommendation to begin screening at age 45 years is a qualified recommendation. The recommendation for regular screening in adults aged 50 years and older is a strong recommendation. The ACS recommends (qualified recommendations) that: 1) average-risk adults in good health with a life expectancy of more than 10 years continue CRC screening through the age of 75 years; 2) clinicians individualize CRC screening decisions for individuals aged 76 through 85 years based on patient preferences, life expectancy, health status, and prior screening history; and 3) clinicians discourage individuals older than 85 years from continuing CRC screening. The options for CRC screening are: fecal immunochemical test annually; high-sensitivity, guaiac-based fecal occult blood test annually; multitarget stool DNA test every 3 years; colonoscopy every 10 years; computed tomography colonography every 5 years; and flexible sigmoidoscopy every 5 years. CA Cancer J Clin 2018;68:250-281. © 2018 American Cancer Society.

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“…Although there is very limited empirical evidence on screening outcomes in adults younger than 50 years (because of the traditional starting age of 50 years in research studies and clinical practice), the qualified recommendation that average‐risk adults begin screening at age 45 years is based on the prolonged trends in disease burden showing increases in CRC incidence and mortality in adults younger than 55 years and modeling analyses showing efficient strategies for CRC screening starting at age 45 years . The underlying evidence pertaining to rising incidence in adults younger than 55 years was discussed in detail in the guideline article and was summarized in last year's annual cancer screening update …”

“…In 2017, the USMSTF screening guideline stated that, “the scientific rationale for beginning screening earlier includes the higher overall incidence rates and younger mean age at onset of CRC in African Americans.” Over the years and recently, these recommendations have been put forth, justifiably in our judgment, based on the higher burden of disease; in each instance, the lack of evidence on screening outcomes in this group was noted. However, when the ACS Guideline Development Group was evaluating the evidence to determine whether a younger age to start screening should be recommended for blacks as well as American Indians and Alaska Natives, it became evident that the incidence rate of CRC for individuals younger than 50 years was no longer higher in blacks compared with whites . On the basis of this observation, the ACS evaluated simulations of CRC screening scenarios by age, sex, and ethnicity using 2 of the 3 Cancer Intervention and Surveillance Modeling Network models that also were used by the USPSTF but were modified to reflect the higher incidence observed in younger cohorts and expected to carry forward into the age groups targeted for screening .…”