Interim FDG-PET SUV Variation Adds Prognostic Value to Deauville 5-Point Scale in the Identification of Patients with Ultra-High-Risk Diffuse Large B Cell Lymphoma.

Introduction: Interim response evaluation by F-fluorodeoxyglucose positron emission tomography/computed tomography (iPET) in diffuse large B cell lymphoma (DLBCL) could be important to rule out disease progression and has been suggested to be predictive of survival. However, treatment guidance by iPET is not yet recommended for DLBCL in clinical practice. We aimed to compare the predictive value of iPET when utilizing the visual Deauville 5-point scale (DS) and the semiquantitative variation of maximum standardized uptake value (ΔSUV).

Materials And Methods: We included 85 patients diagnosed with DLBCL and uniformly treated with standard protocols. iPET with DS of 1-3 and/or ΔSUV ≥66% was defined as negative. Univariable and multivariable Cox regression analyses were performed to determine the independent factors affecting progression free survival (PFS) or overall survival (OS) and to estimate PFS and OS.

Results: iPET positivity, measured by DS or ΔSUV, showed predictive value of disease refractoriness, improved by combining DS and ΔSUV. After a median follow-up of 50.1 months, iPET was an independent predictor for both PFS and OS when interpreted by DS, but only for PFS by ΔSUV. Combined visual and semiquantitative analysis (D4-5 & ΔSUV<66%) was an independent predictor of PFS and OS, and allowed to identify an ultra-high-risk subgroup of patients with very dismal outcome, increasing the discriminating capacity for iPET.

Conclusion: Our study suggests that combined DS and ΔSUV in iPET assessment predicts refractory disease and distinguishes ultra-high-risk DLBCL patients with a very dismal prognosis, who may benefit from PET-guided therapy adjustment.