Effects of screening for colorectal cancer: Development, documentation and validation of a multistate Markov model

Clin Transl Gastroenterol

Cardoso

Guo

et al. 2021

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INTRODUCTION: The performance of colorectal cancer (CRC) screening programs depends on the adherence to screening offers. However, identical adherence levels may result from varying patterns of the population's screening behavior. We quantified the effects of different adherence patterns on the long-term performance of CRC screening for annual fecal immunochemical testing and screening colonoscopy at 10-year intervals. METHODS: Using a multistate Markov model, we simulated scenarios where, while at the same overall adherence level, a certain proportion of the population adheres to all screening offers (selective adherence) or the entire population uses the screening offers at some point(s) of time, albeit not in the recommended frequency (sporadic adherence). Key outcomes for comparison were the numbers of prevented CRC cases and prevented CRC deaths after 50 simulated years. RESULTS: For screening with annual fecal immunochemical testing at adherence levels of 10%–50%, ratios of prevented CRC cases (CRC deaths) resulting from a sporadic vs a selective pattern ranged from 1.8 to 4.4 (1.9–5.3) for men and from 1.7 to 3.6 (1.8–4.4) for women, i.e., up to 4–5 times more CRC cases and deaths were prevented when the population followed a sporadic instead of a selective adherence pattern. Comparisons of simulated scenarios for screening colonoscopy revealed similar patterns. DISCUSSION: Over a lifelong time frame, large numbers of irregular screening attendees go along with much larger preventive effects than small numbers of perfectly adhering individuals. In clinical practice, efforts to reach as many people as possible at least sporadically should be prioritized over efforts to maximize adherence to repeat screening offers.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Strongly Divergent Impact of Adherence Patterns on Efficacy of Colorectal Cancer Screening: The Need to Refine Adherence Statistics

Clin Transl Gastroenterol

Cardoso

Guo

et al. 2021

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“…Differences in risk reduction estimates likely result from two factors. First, COSIMO was developed for the German screening-eligible population, 14 thereby reflecting correspondingly higher absolute lifetime CRC risks than, for instance, in the US population. 29,30 Higher absolute risks may imply greater benefits of screening, which is also mirrored in the larger absolute numbers of LYG in our study compared to modeling for the US population.…”

Section: Findings In Contextmentioning

confidence: 99%

Model based evaluation of long‐term efficacy of existing and alternative colorectal cancer screening offers: A case study for Germany

Hoffmeister

Brenner

2021

Intl Journal of Cancer

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For individuals willing to minimize their lifetime risk of colorectal cancer (CRC), the most effective screening approach remains unclear. Here, we sought to compare the long-term performance of existing and alternative CRC screening offers in a case study for Germany. Applying the perspective of a perfectly adhering man or woman at average risk, we used COSIMO, a validated Markov-based multistate model, to simulate the effects of current CRC screening offers in Germany. These include ageand sex-dependent offers for fecal immunochemical testing (FIT) or screening colonoscopy, which may be used twice starting at age 50 in men and age 55 in women.For comparison, we modeled screening colonoscopies at ages 50, 60 and 70, screening colonoscopies at ages 50 and 60, followed by biennial FITs and conventional FITbased strategies at varying intervals. We found that the highest reductions in lifetime risks of developing (76%-84%) and dying from CRC (82%-90%) were achieved by three colonoscopies, followed by annual FIT screening and strategies combining both modalities. In men, additional screening from age 70 onwards reduced the risk of dying from CRC by another 9% units and resulted in 32 to 39 additional life-yearsgained per 1000 individuals. Among women, three colonoscopies outperformed current screening offers in all outcomes, at little risk of screening-related complications.In summary, several FIT-and colonoscopy-based offers yield comparably high CRC risk reductions, including approaches combining both modalities. German screening offers may be optimized by lowering the eligibility age for screening colonoscopy for women, along with additional offers for the elderly.

“…For this study, we used the previously developed and validated Markov-based Co lorectal Cancer Multistate Si mulation Mo del (COSIMO) to simulate effects of screening for CRC in a hypothetical German population [8]. Briefly, COSIMO simulates the natural history of CRC based on the process of precursor lesions developing into preclinical and then clinical cancer in a hypothetical population for a predefined number of years.…”

Section: Methodsmentioning

confidence: 99%

Making colonoscopy-based screening more efficient: a ‘gateopener’ approach

Cardoso

Niedermaier

et al. 2021

Preprint

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Objectives To assess the potential of an innovative approach to colonoscopy-based screening for colorectal cancer (CRC), by use of a single, low threshold fecal immunochemical test (FIT) as a "gateopener" for screening colonoscopy. Design Simulation study using COSIMO, a validated Markov-based simulation model, in a hypothetical German population. Setting Modelled scenarios included either direct invitation to screening colonoscopy or mailing a single ("gateopener") FIT along with an invitation to colonoscopy contingent on a FIT value above a low threshold yielding a 50% positivity rate (e.g., every other pre-test will be positive). The main analyses focused on scenarios assuming identical colonoscopy uptake, resulting from higher adherence to the gateopener FIT than to primary use of colonoscopy and avoidance of colonoscopy in those with below-threshold FIT values. Participants Hypothetical cohorts of 100,000 previously unscreened men and women using screening at different ages and with varying levels of adherence. Interventions Screening colonoscopy without and with preceding gateopener FIT. Main outcome measure Detected and prevented CRC cases and deaths within 10 years. Results Across all ages and both sexes, use of screening colonoscopy contingent on a positive gateopener FIT yielded approximately doubled cancer detection rates as compared to conventional screening. In those spared from undergoing screening colonoscopy due to a negative FIT pretest, numbers needed to screen were 10-times higher as compared to those for individuals with a positive FIT, peaking in more than 2500 and more than 3800 (hypothetically) needed colonoscopies to detect one case of cancer in 50-year-old men and women, respectively. At identical levels of colonoscopy use, gateopener screening resulted in 51-53% and 63-68% more prevented CRC cases and deaths, respectively. Conclusions By directing colonoscopy capacities to those most likely to benefit from it, offer of screening colonoscopy contingent on a "gateopener" low-threshold FIT would substantially enhance efficiency of colonoscopy screening.