Baseline volumetric parameters of PET/CT ¹⁸F-FDG and international prognostic index at patients with diffuse B-cell large cell lymphoma

Abstract

INTRODUCTION: Metabolic tumor volume (MTV) and Tumor lesion glycolysis (TLG) are used in 18F-fluorodeoxyglucose Positron-Emission Tomography combined with Computed Tomography (18F-FDG PET/CT) as biometric markers in whole tumor. International prognostic index (IPI) has been used during 30 years at patients with diffuse B-cell large cell lymphoma (DLBCL) for prognosis, use MTV and TLG was unknown. Our aims were to determinate the best statistical relationship between MTV, TLG and IPI in patients with DLBCL.OBJECTIVE: Complex study of baseline volumetric parameters PET/CT with 18F-FDG at patients with DLBCL and assessment of their correlation with prognostic groups.MATERIALS AND METHODS: Baseline 18F-FDG PET/CT performed in 31 primary patients with DLBCL and evaluated SUVmax, MTV, TMTV, TLG, TTLG at different involved anatomic zones; correlation between PET biomarkers and prognostic groups of patients.Statistics: The research materials were subjected to statistical processing using the methods of correlation and regression analyses.RESULTS: SUVmax mean level didn’t discerned at patients of low and high-risk groups, but TMTV has been less in favorable prognostic, than in unfavorable groups (152±3.0 sm3 vs 890±178 sm3 p<0,01); the same TTLG (1291±474 g/ml×sm3 vs 7640±2067 g/ml×sm3 , p<0.01) and IMA (6.7±0.7 vs 9.2±0.6; p<0,01). All volumetric parameters have been less at patients with supradiaphragmatic lymph nodes, than infradiaphragmatic lymph nodes and bones too. Significant positive correlation was found between the TMTV u TTLG (p=0.965; p<0,001), between TMTV, TTLG and progressive disease risk (p=0.735; p=0.747; p<0,001). The regression analysis was derived to estimate the connection PET biomarkers and progressive disease risk.DISCUSSION: The 30-year experience of using IPI in assessing the prognosis of patients with DLBCL has shown its insufficient effectiveness in many clinical situations, and the R-IPI prognostic model has been tested on a smaller number of patients and can only be considered additionally. We studied in detail the initial volumetric parameters of patients with DLBCL in different regions of the lesion and their relationship with the level of prognosis according to the IPI criteria. Our data on large values of volumetric parameters in the infradiaphragmatic areas and bones may be related to the worse prognosis in patients with these localizations. Further broader studies of the initial volumetric biomarkers of PET in DLBCL patients will contribute to the development of approximate boundaries of specific volumetric parameters for different tumor localizations.CONCLUSION: The results obtained showed that the baseline volumetric parameters PET/CT at patients with DLBCL have significant connection with prognostic groups of patients and can be additional factors to influence of tactics of therapy.