Cytogenetic and molecular response of EUTOS risk groups in children with chronic myeloid leukemia chronic phase on imatinib treatment

Introduction Recently (2011), the European Treatment and Outcome Study (EUTOS) scoring system was formulated to risk-stratify chronic myeloid leukemia (CML) chronic phase patients on imatinib treatment. CML during childhood is rare, making prognostication and management difficult. This study was conducted to investigate the cytogenetic and molecular response rates among EUTOS risk groups in pediatric CML patients on treatment with imatinib. Patients and methods Hospital records of pediatric CML chronic phase patients (age≤18 years) from 2009 to 2012 were analyzed retrospectively for demographic data, imatinib dose, date of initiation of treatment, EUTOS risk score, follow-up details, and cytogenetic and molecular response. Results A total of 57 children were included in this study, with a median age of 14.5 years (range: 5–18 years) and male preponderance (M:F, 1.19:1). The majority (67%) of them were in the low-risk group as per the EUTOS score and the remaining were in the high-risk group. Complete hematological response at 3 months was 100% in the lowrisk and 94% in the high-risk group. Complete cytogenetic response at 12 months was 76 and 73% in the low-risk and high-risk groups, respectively. Major molecular response at 18 months was 85 and 79% in the low-risk and high-risk groups, respectively. Two-year event-free survival was 89 and 80% in the low-risk and high-risk groups, respectively. Conclusion The EUTOS low-risk cohort responded better than the high-risk cohort, but the difference was not statistically significant. Both groups had similar outcome at the end of 2 years. The EUTOS score did not predict the response and outcome in pediatric CML.