Novel prognostic index based on hemoglobin level and platelet count for diffuse large B-cell lymphoma, not otherwise specified in the R-CHOP era.

Abstract

The international prognostic index (IPI) is a broadly utilized clinical tool to aid in predicting the prognosis of patients with aggressive non-Hodgkin's lymphomas (NHL). However, since this score was developed before the development of rituximab, and the introduction of combined rituximab plus CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) (R-CHOP) therapy for NHL has dramatically improved clinical outcomes, the IPI may be inadequate to assess prognosis in the R-CHOP era. In the present study, we assessed the utility of hemoglobin (Hb) level and platelet count to predict prognosis in diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), the largest category of aggressive NHL. A total of 89 patients newly diagnosed with nodal DLBCL, NOS and treated with R-CHOP therapy were included. The blood count results at diagnosis were statistically analyzed. Available biopsy specimens were immunostained for interleukin (IL)-6. Hb levels lower than 120g/L (p=0.0133) and platelet counts lower than 135×109/L (p=0.0233) were associated with worse overall survival (OS). Based on those levels as cutoff values, a hemoglobin-platelet (HP) index was calculated by assigning 1 point for an Hb level or a platelet count lower than the cutoff. The patients were divided into three groups based on the HP index: high, with a score of 2 (n=8); intermediate, with a score of 1 (n=39); and low, with a score of 0 (n=42). A higher HP index was associated with worse OS (p=0.0055). Patients with IL-6-positive tumors had significantly lower Hb levels than those with IL-6-negative tumors (p=0.0264), suggesting that abnormal production of IL-6 by lymphoma cells is associated with anemia. On the other hand, there was no association between the platelet counts and the IL-6 expression in the lymphoma cells. In a multivariate analysis, the HP index predicted OS rate independently of the IPI. Since the HP index is based on inexpensive and broadly available laboratory values, we believe that this index will have great utility in clinical practice, and the addition of this index to IPI could more precisely predict prognosis.