Exploring Variations in the Content of Cancer-Specific Treatment Guidelines: An International Cancer Benchmarking Partnership (ICBP) Study

Background: Cancer-specific treatment guidelines aim to provide robust evidence-based recommendations for clinicians to ensure optimal disease management for patients. The content of these guidelines can greatly affect a patients' access to optimal treatment. However, the extent of international variation in guideline content remains understudied. Aim: Phase 2 of ICBP explores several factors that may be contributing to differences in cancer survival outcomes. Module 7 investigates differences in 'access to treatment' across seven participating countries (Canada, Australia, New Zealand, the UK, Ireland, Norway and Denmark). This project specifically aims to explore how variation in guideline content for cancer-specific treatment modalities may be contributing to differences in international survival outcomes. Methods: We reviewed cancer treatment guidelines across the seven ICBP countries that fulfill standard methodological criteria and are widely used in clinical care. This study includes a selected range of national and international guidelines recognizing that some participating countries do not produce their own site-specific guidelines and instead draw on international bodies (e.g., ESMO oncology clinical practice guidelines). We reviewed treatment guidelines for three cancer sites (stomach, pancreas and lung), recording points of content variation that were considered clinically significant and relevant to emerging findings from the ICBP survival benchmarking study. Results: Differences in the content of guidelines were found for each cancer site to varying degrees. Some guidelines showed a large degree of similarity which reflects strong consensuses in the evidence base. Others exhibited stark differences in recommendations for the type of surgical technique implemented, when to administer chemotherapy, use and type of radiotherapy and the extent of palliative care. Some differences may partly be explained by differences in the timeliness of some bodies to produce new guidelines, while others may stem from differences in how bodies evaluate the robustness and validity of high-profile phase III trials. Conclusion: This study found variation in the content of treatment guidelines. The extent to which this variation contributes to differences in international cancer outcomes warrants further exploration, as does additional content analyses of national guidelines for low- and middle-income countries. Our findings may prompt a move by clinical and policy stakeholders toward the standardization of international treatment guidelines, particularly in cases where content variation is marginal and given that guideline development processes are highly labor- and resource-intensive. This study also highlights the need to improve communications between national and international guideline bodies, when recommendations vary significantly, to reach international consensuses on areas of controversy regarding cancer site-specific treatment modalities.