Validation of Models Used to Inform Colorectal Cancer Screening Guidelines
MetadataShow full item record
Background: Microsimulation models synthesize evidence about disease processes and interventions, providing a method for predicting long-Term benefits and harms of prevention, screening, and treatment strategies. Because models often require assumptions about unobservable processes, assessing a model's predictive accuracy is important. Methods: We validated 3 colorectal cancer (CRC) microsimulation models against outcomes from the United Kingdom Flexible Sigmoidoscopy Screening (UKFSS) Trial, a randomized controlled trial that examined the effectiveness of one-Time flexible sigmoidoscopy screening to reduce CRC mortality. The models incorporate different assumptions about the time from adenoma initiation to development of preclinical and symptomatic CRC. Analyses compare model predictions to study estimates across a range of outcomes to provide insight into the accuracy of model assumptions. Results: All 3 models accurately predicted the relative reduction in CRC mortality 10 years after screening (predicted hazard ratios, with 95% percentile intervals: 0.56 [0.44, 0.71], 0.63 [0.51, 0.75], 0.68 [0.53, 0.83]; estimated with 95% confidence interval: 0.56 [0.45, 0.69]). Two models with longer average preclinical duration accurately predicted the relative reduction in 10-year CRC incidence. Two models with longer mean sojourn time accurately predicted the number of screen-detected cancers. All 3 models predicted too many proximal adenomas among patients referred to colonoscopy. Conclusion: Model accuracy can only be established through external validation. Analyses such as these are therefore essential for any decision model. Results supported the assumptions that the average time from adenoma initiation to development of preclinical cancer is long (up to 25 years), and mean sojourn time is close to 4 years, suggesting the window for early detection and intervention by screening is relatively long. Variation in dwell time remains uncertain and could have important clinical and policy implications.
Showing items related by title, author, creator and subject.
Clarifying differences in natural history between models of screening: The case of colorectal cancerVan Ballegooijen, M.; Rutter, C.; Knudsen, A.; Zauber, A.; Savarino, J.; Lansdorp_Vogelaar, Iris; Boer, R.; Feuer, E.; Habbema, J.; Kuntz, K. (2011)Background. Microsimulation models are important decision support tools for screening. However, their complexity makes them difficult to understand and limits realization of their full potential. Therefore, it is important ...
Comparative economic evaluation of data from the ACRIN national CT colonography trial with three cancer intervention and surveillance modeling network microsimulationsVanness, D.; Knudsen, A.; Lansdorp_Vogelaar, Iris; Rutter, C.; Gareen, I.; Herman, B.; Kuntz, K.; Zauber, A.; Van Ballegooijen, M.; Feuer, E.; Chen, M.; Johnson, C. (2011)Purpose: To estimate the cost-effectiveness of computed tomographic (CT) colonography for colorectal cancer (CRC) screening in average-risk asymptomatic subjects in the United States aged 50 years. Materials and Methods: ...
Gini, A.; Zauber, A.; Cenin, Dayna; Omidvari, A.; Hempstead, S.; Fink, A.; Lowenfels, A.; Lansdorp-Vogelaar, Iris (2018)Background & Aims: Individuals with cystic fibrosis are at increased risk of colorectal cancer (CRC) compared with the general population, and risk is higher among those who received an organ transplant. We performed a ...