Prognostic Value of Lymphopenia and Total Metabolic Tumor Volume in Diffuse Large Cell Lymphoma of B Phenotype

BACKGROUND: Diffuse large cell B lymphoma (DLBCL) is the most common lymphoma in adults. The International Prognostic Index (IPI) has been used since 1993 to assess the severity of the disease. Other prognostic factors have emerged such as total metabolic tumor volume (TMTV) assessed by PET-CT and lymphopenia at diagnosis. The objective of our study was to evaluate the prognostic value of lymphopenia and TMTV in LDGCB in comparison with the IPI score.

METHOD: We constituted a retrospective monocentric cohort of patients treated with R-CHOP or R-ACVBP in 1st line of DLBCL. The TMTV on the initial PET-CT scan was acquired using an artificial intelligence module and was related to the patient volume measured on the scan (TMTV/PV ratio). The effect of prognostic factors on 3-year progression-free survival (PFS) and overall survival (OS) was analyzed by comparison of Kaplan-Meier curves (Log-Rank test) and Cox regression.

RESULTS: 118 patients with a lymphocyte count at diagnosis were included in the survival analysis. Among them, 53 patients underwent PET-CT analysis. Two factors were associated with decreased OS at 3 years: lymphocyte count at diagnosis ≤ 0.7G/L (76.9% vs 93.5%; p = 0.009) and TMTV/VP ratio > 0.35% (81% vs 96.9%; p = 0.05). The combination of these two factors was superior to the IPI score in discriminating patients' 3-year PFS (88.9% if no adverse factors, 55.6% if 1 factor, 12.5% if 2 factors present; p < 0.001).

CONCLUSION: Lymphopenia and elevated TMTV/VP ratio at the diagnosis of LDGCB are individually associated with decreased overall survival of patients. The combination of these two factors is superior to the IPI in our study to discriminate the 3-year progression-free survival of patients.

Pascal:Janssen: Consultancy; Gilead: Consultancy; Roche: Consultancy.