A Phase II Trial of Conformal Radiation Therapy for Pediatric Low-Grade Glioma: 5-year Disease Control and Functional Outcomes
Low-grade gliomas in children are treated with radiation therapy in combination with chemotherapy and/or surgery. This treatment can result in significant functional and cognitive deficits. This study was designed to evaluate the disease outcome and functional deficits in children treated for low-grade gliomas with radiation treatment encompassing tumor plus 10 mm margins, instead of the more conventional margins of 15-20 mm.
78 patients participated, ages 4-13 years. Five-year survival was 98%, with 87% event-free survival (meaning no recurrence of disease over 5 years after treatment), despite the decrease in treatment volume. 40% of patients required growth hormone supplementation 5 years after therapy, and this was closely associated to how much radiation was received to the pituitary gland.
Early puberty was present in 28% of patients, compared with 12% before therapy. IQ did not change, but reading and spelling skills had declined over the 5 years. This was associated with the presence of hydrocephalus and the tumor location. Behavioral scores and visual/auditory learning scores both improved over the 5-year period. Memory appeared to remain the same. There was a small decline in communication skills.
This study shows that good outcomes can be achieved with decreased treatment area, with minimal long term effects on cognitive and behavioral skills. As technology continues to improve and proton therapy becomes more readily available, more research is needed and likely.
Partially funded by an unrestricted educational grant from Bristol-Myers Squibb.