Young Survivors at KSA: registry for standardised assessment of long-term and late-onset health events in survivors of childhood and adolescent cancer-a study protocol.

introductionA high proportion of survivors of childhood and adolescent cancer experience chronic medical conditions - late effects. Most studies on late effects have a retrospective or questionnaire-based design, which leads to unavoidable limitations such as missing data or different severity coding and grading of late effects. We, therefore, need prospective data, including standardised severity coding and grading. 'Young Survivors at KSA' aims to close this gap by assessing frequency, severity, risk factors and longitudinal changes of late effects in childhood cancer survivors prospectively and in a standardised way. METHODS AND ANALYSIS: Within the 'Young Survivors at KSA' registry, we collect data from regular follow-up visits in a comprehensive database prospectively and repeatedly from start of the study and retrospectively at most until January 2016. We classify and grade the severity of late effects according to the Common Terminology Criteria for Adverse Events version 4.0 modified by Hudson TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT04811794; https://clinicaltrials.gov/ct2/show/study/NCT04811794.