The use of the EORTC QLQ-C30 Summary Score, available here, has increased since its publication. Although, there is a debate going on within the EORTC QLG in which context applying the summary score is appropriate. Furthermore, regulatory agencies have expressed concern that the summary score is not specific enough for regulatory decision-making. Therefore, more research is needed on the use of the EORTC QLQ-C30 summary score in both cancer clinical trials and clinical practice settings. Currently, a project aiming to provide recommendations for the use of the EORTC QLQ-C30 summary score in cancer clinical trials and clinical practice. This project is expected to finish by the beginning of 2025.