Characteristics of Global Radiation Therapy Trials Between 2017 and 2022: A Cross-Sectional Study

Abstract

Radiotherapy continues to play a key role in nearly every cancer, yet little is known about contemporary trials evaluating radiotherapy and its ability to advance cancer care in recent years. The purpose of this study is to describe the evolving landscape of global radiotherapy trials over the past five years. In this cross-sectional study, we downloaded the records of all 153,403 clinical studies registered on ClinicalTrials.gov between June 1, 2017 and May 31, 2022 with the primary purpose of "treatment". We then identified radiotherapy trials and did longitudinal descriptive analyses. A total of 3,104 (21%) radiotherapy trials registered at ClinicalTrials.gov were identified. The top 3 countries with radiotherapy trial conducted were the United States (1,259, 40.6%), China (610, 19.7%) and France (212, 6.8%). Despite the steady growing trends of all oncology trials, the number of radiotherapy trials presented a decreasing trend. Furthermore, in contrast to other oncology trials, only 991 radiotherapy trials (31.9%) were sponsored by industry, National Institute of Health (NIH) or other federal agencies from 2017 to 2022 (54.9% vs. 31.9%; P < .001), and the overall trend has been declining year by year. The decreasing trend in the overall numbers, the unequal distribution and the limited funding from industry, NIH or other federal agencies of radiotherapy trials across the world are concerning considering the important role of radiotherapy for cancer treatment. The decline of radiotherapy trials in the past 5 years warrants more discussion and collaboration among oncologists and funding agencies to promote radiotherapy research in the future.