Outcomes of children with chronic myeloid leukemia: A population‐based cohort study

OBJECTIVE: Chronic myeloid leukemia (CML) is a rare disease in childhood. While hematopoietic stem cell transplant (HSCT) was the treatment of choice for CML prior to 2000, the introduction of tyrosine kinase inhibitors (TKIs) changed the management of this disease. This population-based analysis was conducted in the province of Ontario, Canada to gather information on treatment choices and outcomes of childhood CML. METHOD: Using a provincial childhood cancer registry and retrospective review of patient medical records for patients < 18 years diagnosed with CML between 1985 and 2018, data on presenting features, treatment, and outcomes were collected from 52 patients. RESULTS: Patients treated before the introduction of TKIs (before 2002) mainly received HSCT and had an overall survival (OS) of 64% at a median follow up of 6 years. The OS of all patients treated in the TKI era (2002 and after) was 90% at a median follow up of 3 years. All three deaths in the TKI era were related to HSCT complications. Survival of patients who remained on a TKI was significantly improved compared to those who underwent HSCT post-TKI therapy (100% vs 66%, P = .008). TKIs were well tolerated. CONCLUSION: Given the increased mortality associated with HSCT in our cohort, further advances in HSCT may be required to outweigh the benefits of a TKI monotherapy approach in the majority of childhood CML patients. We believe HSCT should be considered in only a limited subset of pediatric patients with CML.