We have analyzed 60 cases of intra-axial brain tumors associated with antecedent 
radiation therapy. These include four new cases. The patients had originally 
received radiation therapy for three reasons: (a) cranial irradiation for acute 
lymphoblastic leukemia (ALL), (b) definitive treatment of CNS neoplasia, and (c) 
treatment of benign disease (mostly cutaneous infections). The number of cases 
reported during the past decade has greatly increased as compared to previous 
years. Forty-six of the 60 intra-axial tumors have been reported since 1978. The 
relative risk of induction of an intra-axial brain tumor by radiation therapy is 
estimated to be more than 100, as compared to individuals who have not had head 
irradiation.