Outcomes and level of evidence in radiation therapy research and different categories of radiotherapy innovations: an ESTRO-VBRO bibliometrics analysis of the literature

Abstract

Aim: The ESTRO-Value-Based Radiation Oncology project aims to enhance patient access to high-value radiotherapy innovations, by identifying interventions delivering meaningful benefit. To understand the role of the quality of evidence in implementation decisions, this paper analyses the study designs and endpoints used to appraise selected types of radiotherapy innovations in the literature. Methods: This review used a quantitative bibliometric approach to analyse a representative set of 23 radiotherapy innovations, identified within the radiation therapy research published between 2012 and 2022 in the Web of Science database. Abstracts were searched manually to extract information about study designs and endpoints. Interventions were allocated into one of four defined radiotherapy categories, based on a decision algorithm developed in a parallel project. Results: 3,721 abstracts were identified and categorised using the decision algorithm into four categories: Drug-centred, Radiation-centred, Radiation-enabling or Operational radiotherapy interventions. The study designs were highly variable across these categories: in Drug-centred innovations, 20.3% were clinical trials compared to 6.8% for Radiation-centred. The predominant design across all categories was Prospective observational studies, ranging from 53.9% in Radiation-enabling to 23.0% in Drug-centred innovations. Regarding endpoints, the main focus for Drug-centred innovations was on Clinical endpoints and Overall survival. For Radiation-centred and Radiation-enabling innovations, Toxicity endpoints were more frequently reported. Conclusion: This analysis demonstrates the differences in radiotherapy research output for various categories of radiotherapy interventions. This supports the development of a tailored appraisal strategy for each category, based on the required level of evidence and meaningful endpoints to support reimbursement and clinical implementation.