Lines of Therapy in Oncology Real-World Data: Navigating Complexity for Robust Evidence

Purpose: The objectives of this session are to introduce the complexity and importance of lines of therapy (LOT) when using real world data (RWD), to summarize insights from ongoing international collaborations reviewing and developing frameworks for oncology LOT, and to engage members in a collective discussion on best practices frameworks and best practices for distinguishing LOT in RWD. Description: Each systemic anticancer treatment line has implications for disease progression, safety, cost, and prognosis. Given the clinical significance, accurately characterizing LOTs is essential for research evaluating treatment use, outcomes, and costs. However, RWD sources, especially large population-based databases, often lack specific or complete information, requiring researchers to make assumptions. Further complicating this, there is no standardized approach among oncologists for defining LOTs in clinical practice, especially across health systems and oncology societies. This symposium brings together RWD and oncology experts to discuss ongoing projects and frameworks aimed at improving LOT the enumeration in cancer RWD. This session will begin with an introduction to LOT concepts, accompanied by a digital handout summarizing session topics and links to online content. The clinical relevance, complexity, and diversity of LOT and RWD in oncology research will be reviewed (15 minutes, Bates). This will be followed by an overview of LOT frameworks developed by the European Society for Medical Oncology (15 minutes, Koopman). A regulatory perspective on using RWD to support real world evidence and the importance of high-quality LOT data will then be shared (15 minutes, Morales). The session will conclude with an audience-panel discussion (15 minutes, Mahmoudpour). Throughout, live polls will engage attendees on their experiences with LOT, perceptions of proposed frameworks, suggestions for next steps, and questions for the panel.