Potential Prognostic and Predictive Role of Monocyte and Lymphocyte Counts on Presentation in Patients Diagnosed With Diffuse Large B-Cell Lymphoma.

INTRODUCTION: Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin's lymphoma. Nearly 40% of patients will die of relapsed disease despite the use of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy. Many prognostic markers established in the chemotherapy era are no longer valid in the rituximab era.

OBJECTIVES: We aim to identify whether we can add absolute lymphocyte count (ALC), absolute monocyte count (AMC), and lymphocyte-to-monocyte ratio (LMR) as new prognostic factors for DLBCL treated with R-CHOP. We also aim to find whether a correlation exists between these variables and the revised International Prognostic Index (R-IPI) score.

METHODS: This is an observational retrospective study done from 2005 to 2015 in Rafic Hariri University Hospital (RHUH), Lebanon, on 42 patients treated with R-CHOP. Patients' data were obtained from medical records. We used receiver operating characteristic (ROC) curve for establishing cutoff values. The chi-square test was used to analyze associations between variables.

RESULTS: Patients were followed for a median of 42 months (24-96 months). Patients with LMR < 2.53 had a significantly worse outcome than those with LMR ≥ 2.53 ( p  < 0.0001). This was also true for patients with ALC < 1.47 × 109 /L ( p  = 0.0163) and AMC > 0.603 × 109 /L ( p  = 0.0053). LMR was also able to risk-stratify patients within each R-IPI category into high- and low-risk patients.

CONCLUSION: ALC, AMC, and LMR, surrogate markers of the host immune system and tumor microenvironment, have prognostic significance in DLBCL patients treated with R-CHOP.