The European Organisation for Research and Treatment of Cancer Quality of Life Group: Past achievements and future priorities in patient-reported outcomes in oncology.

As the EORTC Quality of Life Group (QLG) approaches its 50th anniversary in 2030, this paper reflects on the group's development and outlines strategic priorities emerging from its January 2026 strategy meeting. Its more than 1400 current members from 43 countries work to support that patient reported outcomes (PROs) are measured rigorously, interpreted meaningfully, and valued consistently throughout the cancer care pathway. Since the introduction of it's core questionnaire (EORTC QLQ-C30) in 1993, EORTC QLG measures have become the most widely used in cancer research worldwide. As the cancer care landscape becomes increasingly complex, we highlight the QLG's ongoing impact and long-term sustainability, with the aim of inspiring other international research and oncology networks. We summarise key developments to date, including the design of its modular measurement strategy, whereby core questionnaires are complemented by additional modules and items from the Item Library. Subsequent initiatives have focused on enhancing the relevance and usability of measures in cancer clinical trials, increasing measurement flexibility to support a broader range of purposes including survivorship, economic evaluation, and routine clinical care, and facilitating outcomes interpretation. Our future work will both sustain the legacy of the past 45 years and shape the next era. We outline ongoing developments within the group and the wider research landscape that underscore the need for a clear future strategy, structured around six pillars: Innovation, research, methodology, and implementation; Policy, stakeholder management, and global outreach; Leadership and funding; Internal collaboration; People development; Patient engagement.