Prognostic Significance of Hematological Indices in Malignant Melanoma Treated With Immune Checkpoint Inhibitors

Abstract

Local and systemic inflammation significantly effects tumor progression and its response to therapy. We aim to evaluate the prognostic significance of inflammatory cells, their ratios, and a change in these indices while patients are receiving immune checkpoint inhibitors (ICIs). We retrospectively reviewed 120 malignant melanoma patients who had received any ICIs from 2011 until December 2017 and evaluated the effect of hematological indices on survival and radiographic responses. We followed the trends of these indices at 0, 6, and 12 weeks while on ICIs. Univariate and multivariate survival analyses were performed. The Student t tests and logistic regression were performed as well. Patients with neutrophil to lymphocyte ratio (NLR) <5 and derived neutrophil to lymphocyte ratio (dNLR) <3 had better overall survival and progression-free survival. The objective response rate was significantly higher in patients with absolute neutrophil count (ANC) <5 and dNLR<3 at baseline. Responder to ICIs had downtrending median ANC, NLR, dNLR, and an uptrending median lymphocyte to monocyte ratio compared with those of nonresponders. Moreover, in responders, the decrease in mean ANC, NLR, and dNLR were statistically significant compared with that of nonresponders at 6 and 12 weeks while on ICIs. Hematological indices can predict the response to ICIs and prognosis in malignant melanoma. Besides, the changes in these indices from their baseline values could be monitored in real-time to predict an earlier response even before a radiographic evaluation. However, the prospective and validation studies are needed before these models can be used in routine clinical practices.