Background. Studies on the long-term treatment outcomes of childhood acute lymphoblastic leukemia (ALL) in resource-limited countries are scarce. The purpose of this study was to assess the evolution of survival outcomes of pediatric ALL in a tertiary care center in Thailand over a 40-year period. Patients and methods. We retrospectively reviewed the medical records of pediatric patients who were diagnosed with ALL and treated at our center between June 1979 and December 2019. We classified the patients into 4 study periods depending on the therapy protocol used to treat the patients (period 1: 1979-1986, period 2: 1987-2005, period 3: 2006-2013, and period 4: 2014-2019). The Kaplan Meier method was used to determine overall and event-free survival for each group. The log-rank test was used to identify statistical differences. Results. Over the study period, 726 patients with ALL were identified, 428 boys (59%) and 298 girls (41%), with a median age at diagnosis of 4.7 years (range: 0.2–15 years). The study periods 1, 2, 3, and 4 had 5-year event-free survival (EFS) rates of 27.6%, 41.6%, 55.9% and 66.4%, and 5-year overall survival (OS) rates of 32.8%, 47.8%, 61.5%, and 69.3%, respectively. From period 1 to period 4, both the EFS and OS rates increased significantly (p<0.0001). Age, study period, and white blood cell (WBC) count were all significant prognostic indicators for survival outcomes. Conclusions. The overall survival of patients with ALL treated in our center improved significantly over time from 32.8% in period 1 to 69.3% in period 4.
BACKGROUND: Few studies have examined survival in relapsed childhood acute lymphoblastic leukemia (ALL) in resource-limited countries. The aims of this study were to evaluate the incidence, prognostic factors, and survival of relapsed childhood ALL in Thailand. METHODS: The medical records of patients with ALL aged <15 years in the major tertiary care institution in Southern Thailand between January 2000 and December 2019 were retrospectively reviewed. The Kaplan-Meier method was used to depict the overall survival (OS). RESULTS: A total of 472 patients with ALL were enrolled. The incidence of relapsed ALL was 32.8%. Of the 155 relapsed patients, 131 (84.5%) and 24 (15.5%) had B-cell and T-cell phenotypes, respectively. One hundred thirteen (72.9%) and 42 (27.1%) patients had early and late relapses, respectively. The most common site of relapse was bone marrow in 102 patients (65.8%). One hundred twenty-eight (82.6%) and 27 (17.4%) patients received or refused the relapse chemotherapy, respectively. The 5-year OS of all relapsed patients was 11.9%. The 5-year OS among the patients with early relapse was significantly lower than in the patients with late relapse (5.3% vs. 29.1%, respectively, p <0.0001). Site and immunophenotype were not associated with survival of relapsed ALL. The patients who refused chemotherapy had a median survival time of 3.1 months. CONCLUSION: The relapse rate was one third of patients with ALL. The 5-year OS was 12% and patients who refused chemotherapy had a median survival time of 3 months.