Should the cut-off values of the lymphocyte to monocyte ratio for prediction of prognosis in diffuse large B-cell lymphoma be changed in elderly patients?

Objectives: A recent study suggested a prognostic role for the peripheral blood absolute lymphocyte/monocyte ratio (LMR) at diagnosis of diffuse large B-cell lymphoma (DLBCL). Here, we investigated the significance of LMR in DLBCL patients in relation to advanced age. Methods: We examined the prognostic impact of LMR in 603 DLBCL treated with rituximab plus CHOP, using the receiver operating characteristic curve analysis for optimal cut-off values, and performed a subgroup analysis according to age. Results: In elderly groups (age ≥ 70), absolute monocyte count was significantly increased, whereas LMR was significantly decreased compared to younger groups. Patients under 70 yr of age with LMR <3.04 had significantly lower overall survival (OS) and progression-free survival (PFS) compared to those with LMR ≥3.04 (P < 0.001 for both). However, in elderly patients (age ≥ 70), there was no significant difference in OS between patients' LMR levels using the 3.04 cut-off value (P = 0.059). Therefore, a new LMR cut-off value of 2.36 was selected in elderly patients, having observed that elderly patients with LMR <2.36 had significantly lower OS compared to those with LMR ≥2.36 (P = 0.021). In multivariate analysis, LMR remained a significant prognostic factor for OS (P = 0.004) or PFS (P < 0.001). Conclusions: We suggest the use of a different cut-off value of LMR in elderly patients to distinguish high-risk from low-risk groups.