The Evolution, Implications and Implementation of Australia’s Surveillance Guidelines for Conventional Adenomas and Serrated Lesions of the Colorectum in a Digital Age
Date
2025
Authors
Ow, Tsai-Wing
Editors
Advisors
Rayner, Chris
Tse, Edmund
Tse, Edmund
Journal Title
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Thesis
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Abstract
Introduction: Colorectal cancer (CRC) rates in Australia are currently amongst the highest in the world. Surveillance colonoscopy programs can reduce CRC-related mortality and morbidity through the identification of early cancers and removal of their precursors. In 2018, Australia’s adenoma surveillance guidelines were updated to include the most recent published data. Multiple changes were introduced which aimed to improve the rationalisation of colonoscopy resources, but these substantially increased the complexity of the guidelines. However, the current literature has yet to explore the effects of these changes on resource utilisation and their ability to be adequately implemented. Furthermore, the role of simple digital tools to aid the adoption of complex guidelines is unclear. Aims: The aims of this thesis were: 1. To explore the changes introduced into the recently revised Australian surveillance guidelines, specifically in comparison to those of other similar Western regions (Europe, USA, United Kingdom). 2. To measure the quality of colonoscopy procedures and determine which factors influence these key outcomes measures in Australia. 3. To compare the change in resource requirements between the new and old surveillance guidelines. 4. To determine whether a digital application could significantly improve the ability of users to adhere to the new guideline recommendations. Methods: A literature review was undertaken concerning colorectal cancer and colonoscopy surveillance guidelines in Australia with a focus on their development, guideline adherence, and methods to improve their implementation. The differing approaches to colorectal adenoma surveillance in the West were also compared. To examine the quality of colonoscopy locally, we compiled a retrospective database of colonoscopies across five hospitals and used key performance indicators to benchmark each site, and identify potential areas for improvement. Using the data on adenoma detection from the colonoscopy database, we then modelled both the new and old surveillance guidelines to evaluate the difference in procedural resources required to implement them. Finally, we tested clinicians using simulated scenarios in a randomised cross-over controlled design to evaluate the potential benefit of a digital tool for the determination of guideline-concordant screening and surveillance recommendations. Results: From our retrospective analysis, we found that inadequate bowel preparation occurred in 7.3% of procedures. 97.5% of adequately prepared procedures were successfully completed. The pooled cancer, adenoma, and serrated lesion detection rates were 3.5%, 40%, and 5.9%, respectively. Two out of five hospitals failed to meet currently accepted criteria for quality in colonoscopy in Australia. Significant differences were found in patient ages, work-force composition, and adenoma detection rate between hospitals (P < 0.001). Medical specialists had a higher adenoma detection rate than surgical specialists (OR 1.53, CI 1.21-1.94, P < 0.001). Cancer detection was independently associated with patient age (OR 1.04; P < 0.001) and with procedures performed by surgical specialists (OR 1.85; P = 0.04). However, adenoma detection was independently associated with patient age (OR 1.04; P < 0.001) and female sex (OR 1.89; P<0.001), and with procedures performed by medical specialists (OR 1.41; P = 0.002). The application of the latest guidelines increased the number of surveillance colonoscopies at 1 year (RR 1.57, P = 0.009) and 10 years (RR 3.83, P < 0.001) and reduced the number required at under 1 year (RR 0.08, P = 0.002), 3 years (RR: 0.51, P < 0.001) and 5 years (RR: 0.59, P < 0.001). The overall effect of new guideline adoption was a reduction in surveillance procedures of 21% over 10 years, increasing to 22% when excluding patients who would be aged over 75 years at the recommended surveillance time. A digital application increased the concordance of guideline-concordant screening and surveillance recommendations by 40% (14/18 vs 10/18, P < 0.001). Application usability was found to be moderately correlated with user ability to correctly determine the appropriate guideline recommendation. Conclusions: Although the overall quality of colonoscopy meets Australia’s national quality benchmarks, significant variations in performance between hospitals and between proceduralists of different specialties highlight the need for individual monitoring and that there is room for further improvement. Despite the increased complexity of the newer guidelines, their adoption could result in a 21-22% reduction in colonoscopy resources over 10 years. This would provide additional incentive for their use, especially considering the resource limitations in the public government-funded health sector in Australia. A well-designed digital tool could provide a simple and effective method to aid users in adopting the latest screening and surveillance guidelines.
School/Discipline
Adelaide Medical School
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 2025
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