Prognostic value of interim and end-of-treatment 18F-FDG PET/CT in patients with diffuse large B-cell lymphoma

Abstract

Objective To compare the value of interim and end-of-treatment 18F-fluorodeoxyglucose (FDG) PET/CT for the prognosis of patients with diffuse large B-cell lymphoma (DLBCL). Methods A total of 116 DLBCL patients (male∶female=1∶1.32, average age: (57.87±15.89) years) whose initial treatment was rituximab+ cyclophosphamide+ doxorubicin+ vincristine+ prednisone(R-CHOP), were enrolled from 2008 to 2016. All patients underwent pre-treatment, interim and end-of-treatment 18F-FDG PET/CT. End points were progression-free survival (PFS) and overall survival (OS). Correlation between metabolic parameters including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), Deauville score (DS), ΔSUVmax, ΔMTV, ΔTLG in the interim PET/CT and those in the end-of-treatment PET/CT was analyzed with Pearson correlation analysis. The ability of metabolic parameters to assess the prognosis was evaluated by receiver operating characteristic(ROC) curve analysis. The survival was analyzed by Kaplan-Meier method and hazard ratio (HR) was calculated by Cox regression model. Results The r values for ΔSUVmax, ΔMTV, ΔTLG of interim and end-of-treatment PET/CT were 0.630, 0.912, 0.955, respectively (all P<0.01). One hundred and four cases (89.7%, 104/116)had the same DS in the interim and end-of-treatment PET/CT, and the r value for DS between two PET/CT scans was 0.733 (P<0.01). The interim metabolic parameters were superior to that at the end of treatment in evaluating the progression. The 5-year PFS(83.1% vs 35.9%, P<0.01; HR=5.969, P<0.01) and OS (95.7% vs 75.5%, P<0.01; HR=8.161, P<0.05) rates were significantly higher in DS 1-3 group than those in DS 4-5 group. Conclusions Interim PET/CT is effective for the prediction of prognosis in DLBCL patients with R-CHOP treatment. Patients with complete remission in the interim can omit the end-of-treatment PET/CT. Key words: Lymphoma, large B cell, diffuse; Prognosis; Positron-emission tomography; Tomography, X-ray computed; Deoxyglucose