Natural History of Rare Tumor Risk Syndromes: A Scoping Review to Inform Cost-Effectiveness Models

# Background Hereditary cancer syndromes account for approximately 10% of all cancers. Many of these, classified as rare tumor risk syndromes (RTRS), lack comprehensive data on natural history, lifetime cancer risk, and the long-term impact of surveillance. These evidence gaps limit the development of decision-analytic disease progression models and cost-effectiveness analyses needed to support healthcare decision-making.