<p>Data collection timeline.</p>

Despite its transformative potential, IO faces challenges in identifying critical research priorities amidst limited funding and resources. The DEFINE-IO study aims to identify the most pressing research priorities in IO to guide researchers, policy makers, and funding bodies in driving innovation and improving cancer outcomes.</p> <p>Methods and analysis</p><p>This study comprises two phases: a modified e-Delphi process and a multi-criteria decision analysis (MCDA).

The e-Delphi process will involve three rounds, with round 1 dedicated to generating research topics, followed by rounds 2 and 3, which will focus on refining and achieving consensus on the identified topics. The final consensus will yield a list of 25 research priorities, which will be evaluated during an in-person MCDA session. These priorities will be assessed against three predefined criteria: urgency, feasibility/equipoise, and affordability, to establish a strategic roadmap for research in IO.</p> <p>Ethics and dissemination</p><p>Formal ethics approval was deemed not necessary.