Long-term follow-up and infectious complications of therapy for acute lymphoblastic leukemia in children

Infection is a major complication of therapy for acute lymphoblastic leukemia (ALL) in children. Recent advances in supportive care have contributed to improvements in long-term survivorship following treatment for ALL. Of 220 children treated for ALL on Dana-Farber Cancer Institute (DFCI) Consortium Protocol 85-001, a retrospective study of all 72 children at the DFCI and Maine Children's Cancer Program was conducted to determine the incidence and impact of infection in pediatric patients not on hematopoietic growth factor support. There were two deaths on therapy, both of which were associated with infection. Our results show that severe infection, requiring hospitalization is far more likely to occur during induction therapy. The risk for hospitalization decreased during therapy, after remission was achieved with fewer children hospitalized during the continuation phase of therapy than during the intensification phase. Fever and neutropenia was the most common reason for hospitalization and in less than 30% of instances an etiology was determined. At a median follow-up of 9 years, the event-free survival (EFS) of the 220 patients enrolled on Protocol 85-001 was 78%. The 9 years EFS by risk groups (standard, high and very high risk) was 89%, 75% and 58%, respectively (p = 0.0005). In conclusion, serious infectious complications were more likely to occur during induction and intensification. Thus, strategies to prevent infection should be targeted to induction and intensification phases of therapy for childhood ALL.