Predictive Effect Of The Peripheral Blood Absolute Lymphocyte Count At The Early Stage Of Induction Therapy For Response To Therapy In Adult ALL

Objective:We investigated the predictive effect of the peripheral blood absolute lymphocyte count (ALC) at the early stage of induction therapy for the response to therapy in adult acute lymphoblastic leukemia (ALL).Methods:From January 2011 to December 2014, a total of 193 adults (age>14 years) with newly diagnosed ALL at the First Affiliated Hospital of Zhejiang University School of Medicine were enrolled in this study。All of these patients were treated with induction chemotherapy in our hospital. Blood cell counts, such as white blood cell count(WBC), absolute neutrophil count(ANC), absolute lymphocyte count(ALC), absolute monocyte count(AMC), blood platelet count(PLT), hemoglobin concentration, were obtained at different time point during induction therapy on dayO, day7, day 14, day21, day28.Firstly, we used PLSDA model analyzing the correlation between the blood cell counts and first complete remission(CR1) rate, and we found ALC on day7, PLT on day28, as well as WBC on dayO were the strongest indexes. And then, receiver operating characteristic (ROC) curve analysis was used to determine the best cut-off value of the ALC-7. Finally, the independent predictive effect of ALC-7 for CR1 was evaluated in univariate and multivariate analysis with bivariate logistic regression model. In addition, we evaluated the predictive effect of ALC-7 for overall survival(OS) and event free survival(EFS) with cox proportional hazard regression model.Result:Predictive effect of ALC-7 for CR1:ALC-7 was an independent predictive factor for CR1, with sensitivity of 36% and specificity of 84%, when the cut-off value was 0.9*109/L. Patients were divided into two groups according to the cut-off value, and the result showed that low ALC-7 group having higher CR1 rate(75.2%vs50%), which means a negative correlation between ALC-7 and CR1. Meanwhile, low ALC-7 group had lower white blood cell count at diagnosis, as well as the minimal residual disease(MRD) after induction therapy.Predictive effect of ALC-7 for OS and EFS:Univariate analysis revealed that ALC-7< 0.90 group having inferior OS(3-year OS rate 15.4% vs 2.3%, P=0.077; HR=0.652, P=0.083) and EFS(3-year EFS rate 12.1% vs 2.3%,P=0.188; HR=0.758,P=0.201), howerver, there was no statistical significance. In multivariate analysis, ALC-7 was an independent prognostic factor for OS (HR=0.420,P=0.001) after adjusting for age, lineage, and white blood cell count.Conclusions:Absolute lymphocyte count on day7 of induction therapy was an independent and specific predictive factor for first complete remission rate, at the same time, it could predict overall survival in adult ALL. Another independent queue is needed to verify these results of our study.