Abstract
In the era of rituximab, the International Prognostic Index (IPI) has been inefficient in initial risk stratification for patients with R-CHOP-treated diffuse large B-cell lymphoma (DLBCL). To estimate the predictive values of PET/CT quantitative parameters and three prognostic models consisting of baseline and interim parameters for three-year progression-free survival (PFS), we conducted an analysis of 85 patients in China with DLBCL underwent baseline and interim PET/CT scans and treated at the Department of Hematology of Peking University Third Hospital from November 2012 to November 2017. The PET/CT parameters, viz. the baseline and interim values of standardized uptake value (SUV(max) ), total metabolic tumor volume (TMTV), and total lesion glycolysis (TLG), and their rates of change, were analyzed by a receiver operating characteristics curve, Kaplan-Meier analysis, and log-rank test. Besides, the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) was also included in the multivariate Cox hazards model. Owing to the strong correlation between TMTV and TLG at baseline and interim (Pearson's correlation coefficient, r = 0.823, P-value = 0.000, and 0.988, P-value = 0.000, respectively), only TLG was included in the multivariate Cox hazards model, where TLG(0) > 1036.61 g and %ΔSUV(max) < 86.02% showed predictive value independently (HR = 10.42, 95% CI 2.35-46.30, P = 0.002, and HR = 4.86, 95% CI 1.27-18.54, P = 0.021, respectively). Replacing TLG in the equation, TMTV(0) and TMTV(1) both showed significantly predictive abilities like TLG (HR = 8.22, 95% CI 1.86-32.24, P = 0.005, and HR = 2.96, 95% CI 1.16-7.54, P = 0.023, respectively). After dichotomy, NCCN-IPI also gave a significant performance (P = 0.035 and P = 0.010, respectively, in TLG and TMTV models). The baseline variables, that is, TMTV(0) , TLG(0) and dichotomized NCCN-IPI, and the interim variables TMTV(1) and %ΔSUV(max) , presented independent prognostic value for PFS. In prognostic model 2 (TLG(0) + %ΔSUV(max) ), the group with TLG(0) > 1036.61 g and %ΔSUV(max) < 86.02% recognized 19 (82.6%) of the relapse or progression events, which showed the best screening ability among three models consisting of baseline and interim PET/CT parameters.