Stress-Testing US Colorectal Cancer Screening Guidelines: Decennial Colonoscopy from Age 45 is Robust to Natural History Uncertainty and Colonoscopy Sensitivity Assumptions

Abstract

PurposeThe 2023 American College of Physicians (ACP) guidelines for colorectal cancer (CRC) screening are at odds with the United States Preventive Task Force (USPSTF) guidelines, with the former recommending screening starting at age 50 y and the latter at age 45 y. This article "stress tests" CRC colonoscopy screening strategies to investigate their robustness to uncertainties stemming from the natural history of disease and sensitivity of colonoscopy.MethodsThis study uses the CRC-SPIN microsimulation model to project the life-years gained (LYG) under several colonoscopy CRC screening strategies. The model was extended to include birth cohort effects on adenoma risk. We estimated natural history parameters under 2 different assumptions about the youngest age of adenoma initiation. For each, we generated 500 parameter sets to reflect uncertainty in the natural history parameters. We simulated 26 colonoscopy screening strategies and examined 4 different colonoscopy sensitivity assumptions, encompassing the range of sensitivities consistent with prior tandem colonoscopy studies. Across this set of scenarios, we identify efficient screening strategies and report posterior credible intervals for benefits of screening (LYG), burden (number of colonoscopies), and incremental burden-effectiveness ratios.ResultsProjected absolute screening benefits varied widely based on assumptions, but strategies starting at age 45 y were consistently in the efficiency frontier. Strategies in which screening starts at age 50 y with 10-y intervals were never efficient, saving fewer life-years than starting screening at age 45 y and performing colonoscopies every 15 y while requiring more colonoscopies per person.ConclusionsDecennial colonoscopy screening initiation at age 45 y remained a robust recommendation. Colonoscopy screening with a 10-y interval starting at age 50 y did not result in an efficient use of colonoscopies in any of the scenarios evaluated.HighlightsColorectal cancer colonoscopy screening strategies initiated at age 45 y were projected to yield more life-years gained while requiring the least number of colonoscopies across different model assumptions about disease natural history and colonoscopy sensitivity.Colonoscopy screening starting at age 50 y with a 10-y interval consistently underperformed strategies that started at age 45 y.

Keywords: cancer screening; colorectal cancer; robust decision making.

Figure 1

Birth cohort incidence risk ratio estimates by model. Shaded areas represent the posterior distribution of adenoma incidence risk ratios by cohort year and model. A gray vertical line crosses the 1940 birth cohort, used as a reference cohort. The horizontal black line at 1 represents the hypothesis of no change in adenoma initiation risk by birth cohort. The vertical gray line, set at 1940, represents the reference cohort against which all other cohorts are compared. The 2 panels present results for the 2 models calibrated independently to the same data. BC-10 and BC-20 refer to the models with a minimum age at adenoma initiation of 10 and 20 y, respectively.

Figure 2

Efficient screening strategies across model specifications. Each symbol represents 1 screening strategy, and the line connecting them approximates the efficient frontier. Shaded areas represent a 95% credible interval for estimates of life-years gained for each strategy. All efficient (i.e., nondominated) strategies are displayed in the graph with a label, and those are the ones that save the most life-years while using fewer colonoscopies. Strategies that are either dominated or extended dominated are omitted from this figure, except for strategies 45–75,10 (United States Preventive Task Force [USPSTF] recommended, represented by a circle if efficient or as a cross otherwise) and strategy 50–70,10 (American College of Physicians [ACP] recommended, represented by a square). A darker, shaded region underneath the frontiers encompasses a 3-day vertical distance to the frontier, which Knudsen et al. used to select “nearly efficient” strategies. Each panel presents 1 model specification.

Figure 3

Robustness of efficiency status by scenario for select strategies. The horizontal axis represents the efficiency status of each strategy, coded as E (efficient), eD (extended dominated), and D (dominated). Colors represent the probability that each strategy will have each efficiency status. Each facet represents 1 colonoscopy screening strategy (columns) for each model specification (rows). The results illustrate that the United States Preventive Task Force (USPSTF)–recommended strategy is sometimes efficient but never dominated, whereas the American College of Physicians (ACP) strategy is almost always dominated and never efficient.