De novo formation of brain tumors in pediatric population following therapeutic cranial irradiation.

PURPOSE: Tumors of central nervous system (CNS) are accounted as the second most common tumors in childhood (21% of all cancers) following hematologic malignancies. The patients can suffer more than one cancer in their lifetime, and radiotherapy is claimed for de novo formation of a new tumor in years after treatment of an initial tumor.
METHODS: We have retrospectively analyzed our database for defining radiotherapy-related de novo brain tumors operated in between January, 2000 and August, 2012. New tumors in the field of radiotherapy were included into the study.
RESULTS: The retrospective analysis revealed six patients (two girls and four boys) eligible for further evaluation. The children were irradiated at an age in the range of 5 and 12 years (mean, 7.8). The primary diagnoses were hematological malignancies in two (acute lymphocytic leukemia and non-Hodgkin lymphoma (NHL)) and solid tumors in other four (two pilocytic astrocytoma, one craniopharyngioma, and one grade 3 astrocytoma). All patients received cranial radiotherapy. The mean latency period for the "second tumor" was 9.5 years. The pathological diagnoses for de novo new tumors were as follows: glial tumor (two cases), medulloblastoma (two cases), mesenchymal tumor (one case), and meningeal sarcoma (one case). All de novo tumors were high graded. Mean survival was 14.6 months.
CONCLUSIONS: de novo brain tumors after irradiation has poor prognosis in neurosurgical practice. Vigilance and awareness for possibility of de novo new tumor are warranted for both families and physicians at follow-ups even years after the treatment of initial tumors.