Validation of the ΔSUV for Interim PET Interpretation in Diffuse Large B-Cell Lymphoma on the Basis of the GAINED Clinical Trial.

The GAINED phase 3 trial (ClinicalTrials.gov identifier: NCT01659099) evaluated a PET-driven consolidative strategy in patients with diffuse large B-cell lymphoma. In this post hoc analysis, we aimed to compare the prognostic value of the per-protocol PET interpretation criteria (Menton 2011 consensus) with the change in the SUV (ΔSUV) alone. Real-time central review of F-FDG PET/CT was performed in 581 patients after 2 cycles (PET2) and 4 cycles (PET4) of immunochemotherapy using the Menton 2011 criteria, combining the ΔSUV (cutoffs of 66% and 70% at PET2 and PET4, respectively) and the Deauville scale. In "special cases," when the baseline SUV was less than 10.0 or the interim residual tumor SUV was greater than 5.0, the Menton 2011 experts' consensus agreed that the ΔSUV may not be reliable and that the Deauville score is preferable. Prognostic values of Menton 2011 and ΔSUV were evaluated by Kaplan-Meier analyses in terms of progression-free survival (PFS). Seventeen percent of patients at PET2 (100/581) and 8% at PET4 (49/581) had PET-negative results by ΔSUV but were considered to have PET-positive results according to Menton 2011 with residual SUV of greater than 5.0. For the population with PET2-positive results, 2-y PFS was 70% (range, 58%-80%) with ΔSUV alone, whereas the outcome tended to be better for those who were considered to have PET-positive results by Menton 2011, 81% (range, 72%-87%). Conversely, all 10 patients with baseline SUV of less than 10.0 had PET2-positive results by ΔSUV but were considered to have PET2-negative results by Menton 2011. These patients had the same 2-y PFS as patients with PET2-negative/PET4-negative results, indicating that the ΔSUV yielded false-positive results in this situation. We recommend the use of the ΔSUV alone rather than the Menton 2011 criteria for assessing the interim metabolic response in patients with diffuse large B-cell lymphoma, except when the baseline SUV is less than 10.0.