Motor performance and functional exercise capacity in survivors of pediatric acute lymphoblastic leukemia

Background: Impaired motor performance and reduced maximum exercise capacity during and after treatment of acute lymphoblastic leukemia (ALL) has been shown. However, no longitudinal study monitoring motor performance after cessation of treatment has been published. Whether sub-maximal exercise capacity is reduced is unknown. Procedure: Motor performance of pediatric ALL survivors, treated with Dutch Childhood Oncology Group ALL-9 protocol was measured with the movement-ABC at stop treatment and ≥5 years later. At follow-up functional exercise capacity was also investigated using the 6-minute walk test (6MWT). Heart rate and oxygen saturation were measured with a portable pulse oximeter before and after the 6MWT. Results: Nineteen boys and 15 girls, median age 12.3 years (range: 9.0-18.7), median time since completion of chemotherapy 5.2 years (5.0-7.1), participated. Mean height/age and weight/age were within the norm, whereas mean BMI/age was significantly increased (mean SDS 0.38, SEM 0.17, P=0.04). Motor performance had improved significantly (P=0.001). In contrast, functional exercise capacity at follow-up was significantly impaired (mean SDS -2.05, SEM 0.13, P<0.001). Conclusions: At ≥5 years after completion of ALL treatment motor performance had improved significantly, but functional exercise capacity was significantly impaired. The exact underlying cause of this late effect needs further study.