Effectiveness in Predicting the Response and Outcome with Three Prognostic Scoring Systems in Pediatric CML CP on Upfront Imatinib

Introduction: The Sokal and Hasford (Euro) scores were developed in the chemotherapy and interferon era and are widely used as prognostic indicators in patients with chronic myeloid leukemia (CML).Recently, European Treatment and Outcome Study (EUTOS) scoring system was introduced. Data on risk stratification in pediatric CML population was lacking due to its rarity [<3%]. Objective: To study the effectiveness in predicting the response and outcome with three prognostic scores in pediatric CML-chronic phase patients on front line Imatinib.

Materials and methods: We retrospectively analyzed the hospital records of newly diagnosed CML CP patients [aged ≤18 years] from 2004 to 2010 for their risk score, cytogenetic response and outcome at the end of 4 years. Outcome was measured in terms of event free survival (EFS) at the end of 48 months. Events include loss of hematological response, loss of cytological response, progression to accelerated/ blast phase (AP/BC). All received free Imatinib under Gleevac international patient assistance program.

Results: Data of 106 children was analyzed with median age of 13.5 years [ranged 5-18 years] and male preponderance [M:F =1.14:1]. The distribution of children was 63%, 32% and 5% in Sokal low, intermediate and high risk respectively, 50%, 43% and 5% in Hasford/Euro low, intermediate and high risk respectively, 71% and 29% in EUTOS low and high risk respectively. The overall cumulative complete hematological response at the end of 3 month was 94%, and complete cytogenetic response at 18 months was 75%. The CCyR at 18 month was seen in 72%,76% and 100% among Sokal low, intermediate and high risk groups respectively, 74%, 73% and 100% among Hasford/Euro low, intermediate and high risk groups respectively, 81% and 86% EUTOS low and high risk groups respectively. The EFS at the end of 48 months was seen in 72%,64% and 83% among Sokal low, intermediate and high risk groups respectively; 70%, 63% and 83% among Hasford/Euro low, intermediate and high risk groups respectively; 73% and 66% EUTOS low and high risk groups respectively.

Conclusion: None of the scoring systems predicted the response and outcome effectively in children with CML CP. Children with EUTOS low risk score had better EFS than high risk score but not statistically significant. These age group CML patients need to be studied and new prognostic scoring systems are needed to risk startify.

Limitation of the study: small sample size, not a prospective study