Predicting primary treatment failure using interim FDG-PET scanning in diffuse large B-cell lymphoma.

Area of Science:

• Nuclear medicine
• Oncology
• Hematology

Background:

• Interim FDG-PET (iPET) is used to adapt therapy in diffuse large B-cell lymphoma (DLBCL).
• Optimal timing and methods for iPET are debated.
• Standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) are assessed.

Purpose of the Study:

• To analyze interim FDG-PET results and patient outcomes in DLBCL.
• To determine the prognostic value of iPET parameters at different time points.
• To identify optimal timing and methodology for iPET in DLBCL treatment adaptation.

Main Methods:

• Retrospective analysis of 200 DLBCL patients' iPET scans (baseline, iPET2, iPET4, end-of-treatment).
• Scans assessed by blinded experts for Deauville score (DS), SUVmax, MTV, and TLG.
• Treatment failure defined as death, progression, or refractory disease.

Main Results:

• No baseline PET parameters predicted event-free survival (EFS) or overall survival (OS) independently of NCCN-IPI.
• At iPET2, DS5 (19.5%) predicted treatment failure (HR 6.29, P < .001); DS4 was similar to DS1-3.
• At iPET4, ΔSUVmax < 66% predicted treatment failure (HR 5.49, P < .001).
• High NCCN-IPI and iPET2 DS5 were negative predictors of survival, independent of novel markers.

Conclusions:

• Deauville score 5 at interim PET after 2 cycles is a strong predictor of treatment failure in DLBCL.
• Changes in SUVmax after 4 cycles also predict treatment failure.
• These findings support the use of iPET for treatment adaptation in DLBCL, with specific timing and scoring providing prognostic information.