Baseline 18F-FDG PET/CT May Portend the Prognosis of Patients With Waldenström Macroglobulinemia/Lymphoplasmacytic Lymphoma After First-Line Treatment

The outcome of patients with Waldenström macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) is variable. We aim to study if baseline 18 F-FDG PET/CT has some prognostic significance in WM/LPL.Thirty-three patients with newly diagnosed WM/LPL who underwent baseline 18 F-FDG PET/CT and received active treatment thereafter were recruited in this retrospective study. Semiquantitative indices of baseline 18 F-FDG PET/CT were measured as total lesion glycolysis (TLG), metabolic tumor volume (MTV), and SUV max . The patients were followed up for at least 3 years or until reaching the endpoint, which were defined as progression-free survival (PFS) and the time to next treatment (TTNT).The overall response rate of the first-line treatment in the recruited patients was 84.8% (28/33). The 3-year PFS and overall survival rates were 56.3% and 89.3%, respectively. Patients with PFS <36 months and TTNT <36 months showed TLG and MTV significantly higher than those with PFS ≥36 months and TTNT ≥36 months ( P < 0.05). SUV max in patients with PFS <36 months was significantly higher than those with PFS ≥36 months ( P = 0.033). Receiver operating characteristic analysis demonstrated that cutoff values of TLG >291.28 SUVbw * mL, MTV >108.78 mL, and SUV max >3.16 were optimal for predicting PFS <36 months. Kaplan-Meier analysis showed that TLG >291.28 SUVbw * mL and MTV >108.78 mL were predictive for shorter PFS ( P = 0.003) and TTNT ( P = 0.002). In multivariate analysis, TLG >291.28 SUVbw * mL and MTV >108.78 mL were independent predictors for shorter PFS (hazard ratio, 3.06; 95% confidence interval, 1.09-8.57; P = 0.033) and TTNT (hazard ratio, 10.01; 95% confidence interval, 2.56-39.22; P = 0.001).The metabolic indices of TLG and MTV in baseline 18 F-FDG PET/CT were independent prognostic factors to predict PFS and TTNT in patients with WM/LPL.