RT Journal Article SR Electronic T1 Combined Visual and Semiquantitative Evaluation Improves Outcome Prediction by Early Midtreatment 18F-FDG PET in Diffuse Large B-Cell Lymphoma JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 999 OP 1005 DO 10.2967/jnumed.119.231621 VO 61 IS 7 A1 Tamás Györke A1 Robert Carr A1 Juliano J. Cerci A1 Claudio Meneghetti A1 Francisca Redondo A1 Monica Celli A1 Charity Gorospe A1 Chirayu U. Auewarakul A1 Linda Jorgov A1 Diana Paez A1 Stefano Fanti YR 2020 UL http://jnm.snmjournals.org/content/61/7/999.abstract AB The purpose of this study was to assess the predictive and prognostic value of interim FDG PET (iPET) in evaluating early response to immunochemotherapy after 2 cycles (PET-2) in diffuse large B-cell lymphoma (DLBCL) by applying 2 different methods of interpretation: the Deauville visual 5-point scale (5-PS) and a change in SUV (ΔSUV) by semiquantitative evaluation. Methods: In total, 145 patients with newly diagnosed DLBCL underwent pretreatment PET and PET-2 assessment. PET-2 was classified according to both 5-PS and percentage ΔSUV. Receiver-operating-characteristic analysis was performed to compare the accuracy of the 2 methods for predicting progression-free survival. Survival estimates, based on each method separately and combined, were calculated for iPET-positive (iPET+) and iPET-negative (iPET−) groups and compared. Results: Both with 5-PS and with ΔSUV-based evaluations, significant differences were found between the progression-free survival of iPET− and iPET+ patient groups (P < 0.001). Visually, the best negative predictive value (NPV) and positive predictive value (PPV) occurred when iPET was defined as positive if the Deauville score was 4–5 (89% and 59%, respectively). Using the 66% ΔSUV cutoff reported previously, NPV and PPV were 80% and 76%, respectively. ΔSUV at the 48.9% cutoff, reported for the first time here, produced 100% specificity along with the highest sensitivity (24%). The 5-PS and a semiquantitative ΔSUV of less than 48.9% for each PET-2 gave the same PET-2 classification (positive or negative) in 70% (102/145) of all patients. This combined classification delivered NPV and PPV of 89% and 100%, respectively, and all iPET+ patients failed to achieve or remain in remission. Conclusion: In this large consistently treated and assessed series of DLBCL patients, iPET had good prognostic value interpreted either visually or semiquantitatively. We determined that the most effective ΔSUV cutoff was 48.9% and that when combined with 5-PS assessment, a positive PET-2 result was highly predictive of treatment failure.