Decreased peripheral blood lymphocyte-monocyte ratio and platelet-monocyte ratio and the Peripheral Blood Score model predict poor survival in peripheral T-cell lymphoma patients

Abstract

Background Peripheral T-cell lymphoma(PTCL) is a group of lymphoproliferative tumors originated from post-thymic T cells or mature natural killer (NK) cells. It shows highly aggressive clinical behaviour, resistance to conventional chemotherapy, and a poor prognosis. Its incidence rate in China is 1 to 2 times higher than in western countries. Therefore, optimal strategies for identifying high-risk patients are urgently needed. Materials and Methods We retrospectively studied 347 newly diagnosed PTCL patients from January 2011 to October 2019 and analyzed the relationship between peripheral blood lymphocyte-monocyte ratio (LMR) and platelet-monocyte ratio (PMR) and prognosis. The model of Peripheral Blood Score was established to screen out high-risk patients. Results The receiver operating characteristic (ROC) curve was used to determine the optimal cut-off value based on survival rate. It was found that patients with PTCL with LMR ≤ 1.68 and PMR ≤ 300 had inferior overall survival (OS) and the difference was significant in both low-risk (P<0.001) and medium high-risk (P<0.001) groups of IPI score. In multivariate analysis, LMR ≤ 1.68 (HR=1.751, 95% CI 1.158-2.647, p=0.006), PMR ≤ 300 (HR=1.762, 95% CI 1.201-2.586, p=0.002), stage III-IV (HR=3.276, 95% CI 1.512-7.099, p=0.003), Eastern Cooperative Oncology Group (ECOG) score 3-5 (HR=2.351, 95% CI 1.647-3.356, p<0.001) and extra-nodal invasion more than one site (HR=1.659, 95% CI 1.125-2.445, p=0.039) were independently associated with short survival. LMR and PMR were integrated into "Peripheral Blood Score (PBS)" model. PTCL patients were divided into three risk groups: low-risk group, medium risk group and high-risk group. The 1-year OS was 86%, 55.3% and 22.6%, and the 3-year OS was 43.4%, 20% and 13.1%, respectively. Conclusion Overall, LMR and PMR can be used as early prognostic indicators in PTCL patients. Moreover, we can easily detect the complete blood cell count (CBC), and use PBS model to preliminarily screen and stratify patients. It is simple, convenient and accurate to screen out patients with short lives, and formulate personalized treatment strategies.