Predictive value of ¹⁸F-FDG PET/CT parameters for interim treatment response in patients with diffuse large B-cell lymphoma

Objective To investigate the predictive value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) parameters for interim treatment response in patients with diffuse large B-cell lymphoma (DLBCL) receiving R-CHOP chemotherapy. Methods A total of 79 DLBCL patients who received R-CHOP chemotherapy in the Affiliated Hospital of Xuzhou Medical University from July 2014 to June 2019 were enrolled. According to their interim treatment response, they were divided into two groups: a complete response (CR) group and an incomplete response (non-CR) group. The differences of pre-treatment PET/CT quantitative parameters were compared between the two groups. The quantitative parameters included the maximum and summary of metabolic tumor volume (MTVmax and MTVsum), the maximum and summary of total lesion glycolysis (TLGmax and TLGsum), and the maximum diameter of the maximum lesion (Dmax). The receiver operating characteristic (ROC) curve was plotted to determine the cut-off values of the above parameters. The multiple logistic regression analysis was perform to evaluate the dependent predictive factors of interim treatment response, while the efficacy of the logistic regression model was assessed by ROC analysis. Results Among the 79 patients, 48 patients were included in the CR group and 31 patients were included in the non-CR group. Statistical differences were found in MTVmax, MTVsum, TLGmax, TLGsum, Dmax, international prognostic index (IPI), lactate dehydrogenase (LDH), the number of extranodal organ involvement and lesion necrosis between the two groups (P＜0.05). The optimal cutoff values for MTVmax, MTVsum, TLGmax, TLGsum and Dmax to predict interim treatment response were 57.2 cm³, 45.3 cm³, 756.0 g, 1 977.1 g and 6.6 cm, respectively, where Dmax had the highest efficacy. Multivariate analysis showed that Dmax and IPI were the independent predictive indicators for interim treatment response. Conclusions ¹⁸F-FDG PET/CT parameters may be used as predictive factors for interim treatment response in DLBCL patients treated with R-CHOP, which can provide important information for the selection and timely adjustment of clinical treatment strategy.