Early changes in lymphocyte/monocyte ratio on-treatment as a prognostic marker to predict overall survival in patients with advanced cancer treated with immune checkpoint inhibitors

Abstract Background A low absolute lymphocyte/monocyte ratio (LMR) in the peripheral blood is associated with poor prognosis in various cancers; however, its role as a predictive biomarker has not been well defined in the era of treatment with immune checkpoint inhibitors (ICI). Methods We queried a database of advanced cancer patients treated with at least one dose of ICI from 2011 to 2017 to study the association of LMR with overall survival (OS). We calculated LMR at baseline and a median of 21 days after the first cycle of ICI (on-treatment LMR), and defined low if < 2 and high if ≥ 2. OS was calculated from the initiation of ICI to date of death or censored at last follow-up. Results 1077 patients met the criteria for this study. Patients with low baseline LMR had a shorter median OS compared to patients with a high baseline LMR (8.5 vs 18.1 months, p < 0.01). In patients with a low baseline LMR, who on-treatment LMR increased to high had longer median OS compared to those whose on-treatment LMR remained low (16.8 vs 7.8 months, p < 0.001). Patients with a high baseline LMR and in whom on-treatment LMR remained high had longer median OS compared to patients with low on-treatment LMR (23.9 vs 9.2 months, p < 0.001). In multivariate analysis, high on-treatment LMR was most strongly associated with longer survival compared to low on-treatment LMR, regardless of baseline LMR. Conclusions Higher baseline and early changes in on-treatment LMR are associated with improved OS in cancer patients receiving ICI.