As immunotherapies continue to evolve, the assessment of disease progression can be challenging to distinguish from immune response. The concept of immune response and its manifestations on medical imaging can have an impact on determining the course of treatment for the patient. The iRECIST criteria aims to reduce the ambiguity of this issue by implementing new evaluation methods for documenting and confirming disease progression. The goal of this webinar is to discuss an operational approach for using the iRECIST criteria in support of oncology clinical trials. The methodology for documenting various imaging data points including establishment and confirmation of progression will be elucidated.