Clinical Validation Of The ELTS Risk Stratification In Chinese Chronic Myeloid Leukemia Patients

Background and ObjectiveChronic myeloid leukemia(CML)is a malignant hematologic disease.Due to the wide application of tyrosine kinase inhibitors,especially the first-generation imatinib(IM),the lifetime expectancy of most patients in chronic phase(CP)could reach a comparable stage to that of the general population,and leukemia was no longer the major cause of death.Based on the current living condition and causes of death,the previous scoring systems were considered to have some defects.Therefore,some scholars have established a new ELTS scoring system.At present,it has proved that the new score had clinical application value in European CML patients,but it has not been verified in Chinese CML patients in the real-world yet.The purpose of our study is to verify that the ELTS risk stratification has the predictive value for the clinical efficacy and survival of Chinese CML-CP patients in the real-world setting,and to compare with the previous Sokal,Hasford and EUTOS scoring methods which were all used for risk stratification.MethodsClinical data of 462 newly diagnosed CML-CP patients treated with IM were analyzed in our hospital from January 2010 to December 2017.Risk stratification was assessed according to ELTS,Sokal,Hasford and EUTOS scores.Combined with therapeutic effect and survival condition of patients,the relationship between each scoring system and complete cytogenetic remission(CCyR)at 18 months,progression-free survival(PFS)at 5 years,overall survival(OS)at 5 years and leukemia-related death(LRD)at 5 years were evaluated.Results1.Risk stratificationAccording to the ELTS score,230 cases(49.8%)were in the low-risk group,168 cases(36.4%)were in the intermediate-risk group,and 64 cases(13.8%)were in the high-risk group.According to the Sokal score,there were 122 cases(26.4%)in the low-risk group,199 cases(43.1%)in the intermediate-risk group,and 141 cases(30.5%)in the high-risk group.According to the Hasford score,there were 135 cases(29.2%)in the low-risk group,266 cases(57.6%)in the intermediate-risk group,and 61 cases(13.2%)in the high-risk group.According to the EUTOS score,there were 411 cases(89.0%)in the low-risk group and 51 cases(11.0%)in the high-risk group.2.Verification resultsCCyR:The ELTS scoring system could effectively distinguish the low-risk group,and the difference was statistically significant when it compared with the high-and the intermediate-risk groups(P<0.001).In contrast,when the Sokal score was used for risk stratification,the cumulative incidence of CCyR was only significantly different between the intermediate-risk group and the low-risk groups(P=0.010).Patients in the low-risk group graded by Hasford score,compared with the intermediate-and high-risk groups,the difference was also statistically significant(P=0.001).And there was no significant difference in the cumulative incidence of CCyR between different groups divided by EUTOS risk stratification(P=0.299).PFS:Having risk strtification with ELTS,compared with the intermediate-and high-risk groups,the proportion of disease progression in the low-risk group was significantly lower,with a statistically significant difference(P=0.013,P=0.022).Date of the previous three scoring systems showed that only EUTOS score could differentiate the different risk groups with significantly different PFS rates(P=0.015),while Sokal and Hasford scores could not effectively identify different risk stratification,and no statistical difference was found.OS:Compared with the whole data,ELTS,Sokal and EUTOS scores could effectively distinguish high-risk groups,which had a high risk of death,except for Hasford score.LRD:During the follow-up period,44 patients died,which mainly for non-leukemia related causes.The major causes of patients in non-LRD group were cardiovascular disease,secondary tumor,lung disease.Our important finding was that,for the cumulative incidence of LRD,comparing of four different scoring methods,there was no significant difference among different risk groups defined by Sokal,Hasford and EUTOS scores,and we could effectively distinguish the incidence of LRD in CML patients by using ELTS scoring system for different risk stratification.Conclusion1.In the real-world,the ELTS score could better judge the prognosis of Chinese CML-CP patients treated with IM.Compared with the evaluation results of several different validation indicators in clinical,the consistency of ELTS scoring system was higher.2.Different from other scoring systems in the past,the important clinical value of ELTS scoring system was that it was the only effective scoring method for distinguishing the incidence of LRD in CML patients with different risk groups.Therefore,it showed a unique advantage in predicting the possibility of LRD.