Baseline PET Total Metabolic Tumor Volume has a prognostic role in PTCLs—Data from International Prospective T‐Cell Project 2.0

Introduction: Peripheral T-cell lymphomas (PTCLs) are a rare, heterogeneous group of hematological malignancies with extremely poor prognosis for almost all subtypes. Functional imaging based on 18-fluorodesoxyglucose positron emission tomography (PET), used for all other lymphoma subtypes, is challenging in PTCLs. Recently, also radiomics, i.e., the extraction of features from the images describing several underlying characteristics of the tumor such as heterogeneity, has demonstrated to provide a better characterization of the disease and reserve some prognostic value, but in this case, no experience in PTCLs lymphoma is available. It has been reported the prognostic value of TMTV in predicting the disease prognosis PTCLs through pre-treatment PET/CT imaging. However, these are limited data on pretreatment evaluation. Patients and methods: This study aimed to investigate whether the metabolic parameters on baseline PET could be used to predict the outcome of PTCL patients, and was conducted as a retrospective analysis of the prospective T-Cell Project 2.0 (NCT03964480). Patients were eligible if a baseline PET was available for central review. Anonymized PET images acquired within TCP 2.0 underwent a central review on WIDEN platform by a pool of nuclear medicine physicians. Tumor segmentation was performed with a percentage threshold of 41% of SUVmax in a lesion. TMTV was defined as sum of MTV through all the lesion of the body. Results: Sixty-six PTCLs patients were enrolled in this study from 8 international centers, and 48 were confirmed eligible and were evaluated in the present study. Median follow-up time was 18 months. PFS and OS at 2 years were 43% and 58% respectively. Median TMTV was 93 ml (25%–75% 30–419). A TMTV of 200 ml was chosen as threshold between high and low risk group for PFS. The same threshold was applied to OS. Overall, 27 patients (56%) were identified as having high TMTV without meaningful differences among PTCL subtypes. Patients with TMTV >200 ml had shorter 2y-PFS and -OS rates (27% and 35%, respectively), compared to patient with lower TMTV (62%, and 82%, respectively) describing both as statistically significant behavior (log-rank of 0.019 for PFS and 0.01 for OS). In univariate analysis, in addition to TMTV >200 ml, B-symptoms, PS >1, stage III/IV, ALC < 1 × 109/L, were adverse prognostic features for PFS, while LDH > UNL, PS > 1, Hb < 12 g/dL, albumin < 3.5 g/dL, and ALC < 1 × 109/L were correlated with lower OS rates. The research was funded by: Associazione Angela Serra Per La Ricerca Sul Cancro Keywords: Aggressive T-cell non-Hodgkin lymphoma, Diagnostic and Prognostic Biomarkers, PET-CT No conflicts of interests pertinent to the abstract.