Interim PET/CT-based prognostic model for the treatment of diffuse large B cell lymphoma in the post-rituximab era

The prognostic accuracy of interim F-18-fluoro-2-dexoy-d-glucose positron emission tomography/computerized tomography (PET/CT) using three different methods of response assessments during rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone chemotherapy was investigated in 186 patients with newly diagnosed diffuse large B cell lymphoma (DLBCL). The response of interim PET/CT was assessed based on a combined evaluation of the Deauville five-point scale (5-PS), the rates of reduction in the maximal standardized uptake value (Delta SUVmax), and the rates of reduction in the metabolic tumor volume (Delta MTV2.5). Positivity on the 5-PS, the optimal cutoff of Delta SUVmax, or the optimal cutoff of Delta MTV2.5 could each predict disease progression. Over a median follow-up of 22.8 months, the assessment of responses based on the 5-PS, Delta SUVmax, and Delta MTV2.5 had prognostic value for progression-free survival. When patients were allocated a score of 0 to 3 depending on the presence of an inadequate response by visual, Delta SUVmax, or Delta MTV2.5, the outcomes of patients with a score of 0 were significantly superior to those with a score of 1, 2, or 3. The interim PET/CT response based on visual, SUV-based, and MTV-based assessment had significant negative predictive value for disease progression and a high potential for predicting outcomes of patients with DLBCL.