Optimizing colorectal cancer screening by race and sex: Microsimulation analysis II to inform the American Cancer Society colorectal cancer screening guideline

Abstract

BACKGROUNDColorectal cancer (CRC) risk varies by race and sex. This study, 1 of 2 microsimulation analyses to inform the 2018 American Cancer Society CRC screening guideline, explored the influence of race and sex on optimal CRC screening strategies.METHODSTwo Cancer Intervention and Surveillance Modeling Network microsimulation models, informed by US incidence data, were used to evaluate a variety of screening methods, ages to start and stop, and intervals for 4 demographic subgroups (black and white males and females) under 2 scenarios for the projected lifetime CRC risk for 40‐year‐olds: 1) assuming that risk had remained stable since the early screening era and 2) assuming that risk had increased proportionally to observed incidence trends under the age of 40 years. Model‐based screening recommendations were based on the predicted level of benefit (life‐years gained) and burden (required number of colonoscopies), the incremental burden‐to‐benefit ratio, and the relative efficiency in comparison with strategies with similar burdens.RESULTSWhen lifetime CRC risk was assumed to be stable over time, the models differed in the recommended age to start screening for whites (45 vs 50 years) but consistently recommended screening from the age of 45 years for blacks. When CRC risk was assumed to be increased, the models recommended starting at the age of 45 years, regardless of race and sex. Strategies recommended under both scenarios included colonoscopy every 10 or 15 years, annual fecal immunochemical testing, and computed tomographic colonography every 5 years through the age of 75 years.CONCLUSIONSMicrosimulation modeling suggests that CRC screening should be considered from the age of 45 years for blacks and for whites if the lifetime risk has increased proportionally to the incidence for younger adults. Cancer 2018;124:2974‐85. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.

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

“…To gain additional understanding of outcomes associated with different screening strategies (particularly starting age) for black and white adults, the ACS commissioned a modeling study by the MISCAN and SimCRC investigators (2 of the CISNET modeling groups) that extended the previous analysis conducted for the USPSTF. The objective was to assess the potential benefit (life‐years gained and CRC deaths averted) and the burden of different CRC screening strategies for black and white women and men . Subsequently, the GDG determined that recent evidence demonstrating a significant increase in CRC incidence among individuals younger than 55 years, which was attributable to a strong birth‐cohort effect, warranted a reevaluation of the optimal age to start screening in the average‐risk population.…”

“…Additional modeling analyses by the MISCAN investigators incorporated recent Surveillance, Epidemiology, and End Results (SEER) incidence data and evaluated screening outcomes for the general US population . Analyses of outcomes for race‐specific and sex‐specific groups by MISCAN and SimCRC, which initially were carried out under the assumption of stable incidence, were repeated to incorporate recent SEER incidence data …”

Cancer screening in the United States, 2019: A review of current American Cancer Society guidelines and current issues in cancer screening

“…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 …”

“…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 . When the models were refined with the updated incidence data, 2 microsimulation models predominately indicated that screening scenarios with a starting age of 45 years had more favorable efficiency ratios than scenarios in which screening started at age 50 years.…”

Cancer screening in the United States, 2018: A review of current American Cancer Society guidelines and current issues in cancer screening

“…The age of 45 years to initiate CRC screening in average‐risk adults is the most significant change from previous ACS CRC screening guidelines . The recommendation for an earlier starting age was based on the prolonged trends in disease burden showing increases in CRC incidence and mortality in persons under age 50 years and modeling analyses showing efficient strategies for CRC screening starting at age 45 years …”