PET/CT Criteria For Early Prediction Of Response To Immune Checkpoint Inhibitor Therapy (PECRIT) (image) Society of Nuclear Medicine Share Print E-Mail Caption These are proposed criteria for early prediction of eventual response to ICI therapy incorporating RECIST-based and PERCIST-based changes seen 3-4 weeks into treatment. Patients whose CT scans, performed 3-4 weeks into therapy, demonstrate an objective response (PR or CR by RECIST 1.1 criteria) are predicted to maintain a response at 4 months. Similarly, progressive disease detected at that same interval predicts continued disease progression at 4 months. In patients with stable disease by RECIST1.1 at 3-4 weeks, an increase > 15.5% in SULpeak of the hottest lesion by PET is associated with eventual clinical benefit (PR or CR at 4 months or SD ? 6 months). The sensitivity, specificity and accuracy of the algorithm to predict response at 4 months were 100 percent, 93.3 percent and 95.0 percent respectively. CR, complete response; PD, progressive disease; PERCIST, PET response criteria in solid tumors; PR, partial response; RECIST, Response Evaluation Criteria In Solid Tumors; SD, stable disease; SULpeak, average standardized uptake value corrected by lean body mass within a 1-cm3 spherical volume of interest. Credit SY Cho, EJ Lipson, H Im, et al., Johns Hopkins University School of Medicine, Baltimore, MD Usage Restrictions Please use at least title and credit Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.