Secondary brain tumors in children treated for acute lymphoblastic leukemia at St Jude Children's Research Hospital

Purpose: To evaluate the incidence of and potential risk factors for second malignant neoplasms of the brain following treatment for childhood acute l ymphoblastic leukemia (ALL). Patients and Methods: The study population consisted of 1,612 consecutively enrolled protocol patients treated on sequential institutional protocols f or newly diagnosed ALL at St Jude Children's Research Hospital (SJCRH) betw een 1967 and 1988. The median fallow-up duration is 15.9 years (range, 5.5 to 29.9 y). Results: The cumulative incidence of brain tumors at 20 years is 1.39% (95% confidence interval [CI], 0.63% to 2.15%). Twenty-two brain tumors (10 hig h-grade gliomas, one low-grade glioma, and 11 meningiomas) were diagnosed a mong 21 patients alter a median latency of 12.6 years (high-grade gliomas, 9.1 years; meningiomas, 19 years). Tumor type was linked to outcome, with p atients who developed high-grade tumors doing poorly and those who develope d low-grade tumors doing well. Risk factors for developing any secondary br ain tumor included the presence of CNS leukemia at diagnosis, treatment on Total X therapy, and the use of cranial irradiation, which was dose-depende nt. Age less than 6 years was associated with an increased risk of developi ng a high-grade glioma. Conclusion: This single-institution study, with a high rate of long-term da ta capture, demonstrated that brain tumors are a rare, late complication of therapy for ALL. We report many more low-grade tumors than others probably because of exhaustive long-term follow-up evaluation. The importance of li miting cranial radiation is underscored by the dose-dependent tumorigenic e ffect af radiation therapy seen in this study. (C) 1998 by American Society of Clinical Oncology.