While the prognosis of acute childhood leukemia has improved, long-term 
survivors are increasingly experiencing late effects of the treatment. Cranially 
irradiated survivors are predisposed to the development of CNS tumors. Our aim 
was to describe the incidence of secondary brain tumors and to define the 
significance of treatment-related risk factors and host characteristics in a 
cohort of childhood leukemia survivors. Our cohort consisted of 60 consecutive 
cranially irradiated adult survivors of childhood leukemia treated in Oulu 
University Hospital (Oulu, Finland); MRI of the brain was performed on 49. The 
sites of the tumors, their histology, and details of the leukemia treatment were 
determined. Of the 49 patients, 11 (22%) 1-8 years of age at the time of 
diagnosis developed meningioma later in life, while no other brain tumors were 
seen. In this cohort, the development of meningioma seemed to show undisputable 
linkage with long latency periods (mean, 25 years; range, 14-34 years) and an 
increasing incidence 20 years after the treatment (47%). Three patients had 
multiple meningiomas, two had recurrent disease, and one had an atypical 
meningioma. Age at the time of irradiation, gender, or cumulative doses of 
chemotherapeutic agents showed no significant association with the development 
of meningiomas. The high incidence of meningiomas in this study was associated 
with long follow-up periods. Although the cohort is small, it seems probable 
that the increasing incidence of meningioma will shadow the future of cranially 
irradiated leukemia survivors. Systematic brain imaging after the treatment is 
therefore justifiable.