SURVIVAL ANALYSIS OF PEDIATRIC ACUTE LYMPHOCYTIC LEUKEMIA ACCORDING TO CHANGES IN RISK GROUP-BASED PROTOCOL: 20 YEARS OF EXPERIENCE

초록

Background and Aims: Recent treatment of acute lymphoblasticleukemia (ALL) is based on risk stratification and survival rates havereached over 70-80%. We investigated the survival rates and prognos-tic factors of pateints with ALL.Methods: This study analyzed patients who were diagnosed with ALLat the pediatrics department Samsugn Medical Center (SMC) between2000 and 2019. Patients were classified under the standard-risk (SR),High-risk (HR), and very HR (VHR) groups. During the study period,SMC protocol of HR group was changed twice. From 2000 to 2005,CCG-1882 protocol was used, from 2006 to 2014 Korean multicen-ter HR ALL-0601 protocol was used, and from 2015 to 2019 Koreanmulticenter HR ALL-1501 protocol was used.Results: Of the 461 patients, the median age at diagnosis was 5.5 yearsold (range 0.1∼26.5 yr) and and those aged 15 years or older were 36(7.8%). At cytogenetic test, Philadelphia chromosome in 24 patients,t(4;11) in 12 patients and hypodiploidy in 3 patients. And 123 patientshad normal chromosome, 100 patients had hyperdiploidy. Completeremission was achieved in 437 patients (94.8%). The 10-year relapsefree survival rate (RFS) was 77.2%, and the overall survival rate (OS)was 83.6% in total patients. The 10-year OS according to the SMCrisk group was 95.5% in the SR group, 83.8% in the HR group, and 81.4% in the VHR group. The 5-year OS according to the treatmentprotocol of HR group was 79.9% in 1882 protocol, 83.0% in 0601 pro-tocol, 96.2% in 1501 protocol treatment group. The prognosis was verypoor with 60.9% of those aged 15 years and older. In addition, relapseoccurred in 61 (13.2%) patients, and their 10-year OS after relapse was33.7%.Conclusions: Treatment outcome of ALL improved markedly. However,the survival rate of relapsed patients is still unsatisfactory. Need tocharacterize AYA patients, and relapsed patients.