Outcome and Prognostic Factors in Pediatric Precursor T-Cell Acute Lymphoblastic Leukemia: A Single-Center Experience / 임상소아혈액종양

ABSTRACT

BACKGROUND: Precursor T-cell acute lymphoblastic leukemia (T-ALL) has worse prognosis than B-cell ALL. We aimed to evaluate prognostic variables in pediatric T-ALL. METHODS: Medical records of 36 T-ALL patients (27 males and 9 females; median age at diagnosis, 10.6 years) diagnosed and treated at Asan Medical Center from 2001 to 2017 were reviewed. Six patients (16.7%) had early T-cell precursor ALL (ETP-ALL). Most patients received the Children's Cancer Group-1882 (CCG1882) or Korean multicenter high risk ALL (ALL0601) protocols and prophylactic cranial irradiation. Clinical features at presentation, response to therapy, and treatment outcomes were analyzed. RESULTS: The six patients with ETP-ALL and 17 of 30 with non-ETP-ALL received CCG1882 or ALL0601 chemotherapy. Three patients, including two with ETP-ALL, did not achieve complete remission after induction. Rapid early response during induction was achieved by 26 patients. Five year overall survival (OS) and event free survival (EFS) rates were 71.4% and 70.2%, respectively. ETP-ALL and slow early response during induction were significant adverse prognostic factors, while hyperleukocytosis at diagnosis was not. CCG1882/ALL0601 chemotherapy resulted in superior survival (OS 78.9%, EFS 73.3%) compared with CCG1901 chemotherapy (OS 64.3%, EFS 64.3%), and patients undergoing prophylactic cranial irradiation had superior EFS to non-radiated patients. CONCLUSION: A high risk ALL protocol with intensified post-remission therapy, including prophylactic cranial irradiation, conferred T-ALL survival outcomes comparable with those of Western studies. Further treatment intensification should be considered for patients with ETP-ALL and slow induction responders. Additionally, CNS-directed treatment intensification, without prophylactic cranial irradiation, is needed.