Prognostic value of the completeness of the metabolic response in patients with diffused large B-cell lymphoma

Abstract

The currently used prognostic factors for long-term results of standard treatment of diffuse large B-cell lymphoma (DLBCL) are not clear enough to predict outcomes. The prognostic significance of interim PET/CT in DLBCL remains controversial. The aim of this study is to determine the predictive value of interim 18 F-FDG PET/CT after first-line treatment in patients with DLBCL. One hundred-eighty patients with DLBCL underwent baseline and interim 18 F-FDG PET/CT scans after 4 cycles of R-CHOP during the period of 2015–2020 at the N. N. Alexandrov National Cancer Centre of Belarus. Interim 18 F-FDG PET/ CT findings were retrospectively correlated to the progression-free survival (PFS) using the Kaplan–Meier analysis. The metabolic response was assessed according Deauville criteria: PET-negative – Deauville 1–2, PET-positive – Deauville 3–5. The International prognostic index (IPI) was used for risk stratification. After 4 cycles of chemotherapy, PET-positive lesions were found in 76 patients and negative scans – in 104 patients. Survival analyses showed highly significant relationships between early interim 18 F-FDG PET/CT imaging and PFS (p < 0.001). For PET-negative patients, the 7-year PFS rate was 91.1 %, for PET-positive patients it is 41.2 %. 5-year PFS rates for PET-negative patients with IPI scores 0–1, 2–3 and 4–5 were 97.5, 93.4 and 66.7 %, respectively. For PET-positive patients, 5-year PFS rates in the same subgroups were 55.6, 50.6 and 23.1 %, respectively. Early interim 18 F-FDG PET/CT imaging is a predictor of PFS in DLBCL. An early assessment of chemotherapy response with 18 F-FDG PET/CT scans may provide useful information on selection of patients for escalated therapeutic strategies.