Excellent therapeutic efficacy and minimal late neurotoxicity in children treated with 18 grays of cranial radiation therapy for high-risk acute lymphoblastic leukemia - A 7-year follow-up study of the Dana-Farber Cancer Institute Consortium Protocol 87-01

BACKGROUND. In the current study, the authors evaluated late neuropsycholog ic effects 7 years after diagnosis and the long-term survival in a cohort o f patients treated for high-risk childhood acute lymphoblastic leukemia (AL L) with cranial radiation therapy. Efficacy and toxicity were evaluated in relation to patient age at diagnosis (age < or <greater than or equal to> 3 6 months). METHODS. Two hundred and one patients treated for high-risk ALL on the Dana -Farber Cancer Institute Consortium Protocol 87-01 were included, 147 of wh om were in continuous complete disease remission and were eligible for cogn itive testing. Sixty-one patients consented to undergo testing. All patient s received 18 grays (Gy) of cranial radiation as a component of central ner vous system treatment. RESULTS. For all 201 patients, the 5-year overall survival (% +/- the stand ard error) was 82% +/- 2 and the 5-year event-free survival (% +/- the stan dard error) was 75% +/- 3. Only two patients developed a central nervous sy stem recurrence. Intelligence quotient (IQ) and memory were at the expected mean for age, but performance on a complex figure drawing task was found t o be reduced. Children who were age < 36 months at the time of diagnosis we re found to have an IQ in the average range, but showed verbal deficits. CONCLUSIONS. The results of the current study demonstrate excellent efficac y of therapy and relatively limited late neurotoxicity on a childhood ALL t herapy protocol in which all evaluated patients had received 18 Gy of crani al radiation. Efficacious therapy that includes cranial radiation does not appear to necessarily incur a heightened risk for significant cognitive imp airment. Cancer 2001;92: 15-22. (C) 2001 American Cancer Society.