The immunotherapy response assessment for neuro-oncology (iRANO) criteria have been developed as a modification of RANO criteria to address the challenges of emerging novel immunotherapy for high-grade gliomas 1. Although these criteria have been primarily for the purposes of standardizing assessment of treatment response in the setting of clinical trials, they offer important guiding principles for everyday reporting.
A form of pseudoprogression is encountered in immunotherapy that is distinct to that seen in routine chemo-radiotherapy (Stupp protocol) both in mechanism and imaging appearances. Furthermore, unlike chemoradiotherapy, the onset of treatment effect in immunotherapy may be somewhat delayed 1.
Key differences between iRANO and RANO criteria
- new lesion outside the main radiation field does not automatically denote progressive disease in iRANO
- iRANO requires a repeat scan to confirm disease progression