Immune-Related RECIST
Modified response evaluation criteria designed to account for unique response patterns seen with immunotherapy treatments.
Full Definition
A specialized set of response assessment criteria (iRECIST or irRECIST) developed to address the unique tumor response patterns observed with immune checkpoint inhibitors and other immunotherapies. Unlike conventional chemotherapy responses, immunotherapy can initially cause apparent tumor enlargement due to immune cell infiltration or inflammation before demonstrating tumor shrinkage, a phenomenon called pseudoprogression. Immune-related RECIST criteria require confirmation of progressive disease with a subsequent scan and allow for the appearance of new lesions without automatically classifying the response as progressive disease. These modified criteria help distinguish true disease progression from immune-mediated inflammation, preventing premature discontinuation of potentially beneficial immunotherapy.
Usage
Usage note: Multiple versions exist (iRECIST, irRECIST); specify which criteria set was used in clinical documentation.
In Context
- "Response assessment was performed using immune-related RECIST criteria to account for potential pseudoprogression." — Clinical trial protocol
- "The apparent progression by RECIST 1.1 was later reclassified as stable disease using immune-related RECIST." — Radiology evaluation