Background <p>Cancer care requires collaboration across specialties, making interprofessional education essential. The INTERACT-EUROPE 100 project promotes interprofessional cancer care by implementing the Inter-Specialty Cancer Training Program (ISCTP) on a larger scale across Europe. This study aimed to co-adapt a comprehensive evaluation framework to assess the impact of the ISCTP, with the broader goal of informing evaluation practices in other educational programs in cancer care. A modified three-round Delphi study was conducted involving cancer care experts and patient representatives. In the first round, 61 participants responded to three open-ended questions in written form to gather their perspectives on key aspects to consider when evaluating the ISCTP. Thematic analysis of these responses yielded twelve overarching statements that were subsequently prioritized by 46 participants in the second round using a ranking task. The third and final round consisted of two cross-national online focus group discussions (<i>n</i> = 15), which allowed for the contextualization of these findings. ISCTP evaluation priorities were defined at various levels: assessing program satisfaction through feedback on content relevance, interactivity (e.g., collaborative exercises), and participant engagement through attendance and active participation. Additionally, emphasis was placed on evaluating both declarative knowledge acquisition and the application of procedural knowledge, as well as competence assessment using culturally sensitive rubrics. Overall, findings underscore the need to measure participant performance through satisfaction, behavioral changes, and patient-centered outcomes to successfully implement existing evaluation frameworks. Having incorporated interest-holder perspectives, these findings provide a robust and patient-centered foundation for a comprehensive ISCTP evaluation.</p>