Unresectable gliomas in children: tumor-volume response to radiation therapy.

Abstract

Serial tumor volume measurements were performed on computed tomographic (CT) scans or magnetic resonance (MR) images of 12 children treated with radiation therapy for high-grade (three children) or low-grade (nine children) astrocytomas of the optic nerve, thalamus, hypothalamus, cerebellar-pontine angle, and pons. Three types of initial tumor response were observed: Tumor volume increased in four children, remained unchanged in one, and decreased immediately after completion of radiation therapy in the others. High-grade tumors regressed maximally within 6 months and low-grade tumors within 10-25 months. All high-grade tumors recurred within 12 months. Three low-grade tumors recurred 3, 6 1/2, and 10 years after diagnosis, respectively. The tumor-volume halving time was 60-78 days for high-grade tumors and 108-330 days for low-grade tumors. The tumor doubling time was 48-60 days for high-grade tumors. The posttreatment increase in tumor volume has implications for radiation treatment planning. It did not indicate a poor prognosis.