Simulation of colorectal cancer screening: what we do and do not know and does it matter

Colonoscopy Colorectal Cancer Screening Programme in Southern Iraq: Challenges, Knowledge Gaps and Future Potential

Data on current colorectal cancer screening practices in Iraq are limited. This study aimed to better understand the current colorectal cancer screening practice and perceived barriers. The project also aimed to use UK expertise to introduce Bowel Cancer Screening Programme (BCSP) in Basra, Iraq. The study consisted of two parts: A pre-visit online survey of clinicians to test the project's feasibility. A public survey was conducted to understand and gauge the general knowledge and perceived barriers to having colorectal cancer screening. The second phase included a short visit to Basra and the delivery of a multidisciplinary meeting for bowel screening colonoscopists. Fifty healthcare providers completed the survey. Basra has no established bowel cancer screening programme, let alone the country. Opportunistic colonoscopy surveillance is done on an ad hoc base. A total of 350 individuals completed the public survey. The survey showed that more than 50% of participants were not familiar with the concept of a BCSP and less than 25% were aware of "red flag" symptoms of bowel cancer. The short visit to Basra included a roundtable discussion and delivered a training workshop for screening colonoscopists using UK training materials in conjunction with the Iraqi Medical Association. Feedback from the course was extremely positive. Several potential barriers were identified to participate in BCSP. The study highlighted potential barriers, including a lack of public awareness and insufficient training resources to be addressed in future screening programmes. The study has identified several potential areas for future collaboration to support the development of a BCSP centre in Basra.

Critical Analysis of Markov Models Used for the Economic Evaluation of Colorectal Cancer Screening: A Systematic Review

BACKGROUND

The economic evaluation of colorectal cancer screening is challenging because of the need to model the underlying unobservable natural history of the disease.

OBJECTIVES

To describe the available Markov models and to critically analyze their main structural assumptions.

METHODS

A systematic search was performed in eight relevant databases (MEDLINE, Embase, Econlit, National Health Service Economic Evaluation Database, Health Economic Evaluations Database, Health Technology Assessment database, Cost-Effective Analysis Registry, and European Network of Health Economics Evaluation Databases), identifying 34 models that met the inclusion criteria. A comparative analysis of model structure and parameterization was conducted using two checklists and guidelines for cost-effectiveness screening models.

RESULTS

Two modeling techniques were identified. One strategy used a Markov model to reproduce the natural history of the disease and an overlaying model that reproduced the screening process, whereas the other used a single model to represent a screening program. Most of the studies included only adenoma-carcinoma sequences, a few included de novo cancer, and none included the serrated pathway. Parameterization of adenoma dwell time, sojourn time, and surveillance differed between studies, and there was a lack of validation and statistical calibration against local epidemiological data. Most of the studies analyzed failed to perform an adequate literature review and synthesis of diagnostic accuracy properties of the screening tests modeled.

CONCLUSIONS

Several strategies to model colorectal cancer screening have been developed, but many challenges remain to adequately represent the natural history of the disease and the screening process. Structural uncertainty analysis could be a useful strategy for understanding the impact of the assumptions of different models on cost-effectiveness results.

The colorectal cancer screening process in community settings: a conceptual model for the population-based research optimizing screening through personalized regimens consortium

Reducing colorectal cancer mortality by promoting screening has been a national goal for two decades. The NCI's Population-Based Research Optimizing Screening through Personalized Regimens (PROSPR) consortium is the first federal initiative to foster coordinated, transdisciplinary research evaluating the entire cancer screening process in community settings. PROSPR is creating a central data repository to facilitate research evaluating the breast, cervical, and colorectal cancer screening process across different patient populations, provider types, and delivery systems. Data are being collected and organized at the multiple levels in which individuals are nested (e.g., healthcare systems, facilities, providers, and patients). Here, we describe a conceptual model of the colorectal cancer screening process guiding data collection and highlight critical research questions that will be addressed through pooled data. We also describe the three research centers focused on colorectal cancer screening with respect to study populations, practice settings, and screening policies. PROSPR comprehensively elucidates the complex screening process through observational study, and has potential to improve care delivery beyond the healthcare systems studied. Findings will inform intervention designs and policies to optimize colorectal cancer screening delivery and advance the Institute of Medicine's goals of effective, efficient, coordinated, timely, and safe health care with respect to evidence-based cancer screening.