PET-derived parameters for response assessment in neoadjuvant atezolizumab: A secondary analysis of PRINCEPS phase II trial

Immune Checkpoint Blockade (ICB) is moving from metastatic to curative setting in different diseases including NSCLC. While for metastatic disease radiological endpoints are currently the standard surrogate marker of benefit from ICBs, based on RECIST or PERCIST criteria, in neoadjuvant setting they often underestimate the response and then pathological response (PR) criteria were developed to evaluate Major PR (MPR), defined as ≤10% viable tumor cells after neoadjuvant treatment, and PR, defined as less than 50% residual tumor cells.