[Combination treatment for pilocytic astrocytoma: stereotaxic radiosurgery and endocavitary radiotherapy].

The treatment of a pilocytic astrocytoma located in a functional area can be performed using radiosurgery. We report a 7 year old male, right-handed, who presented with a pilocytic astrocytoma in the left parieto-occipital lobe. After a 7 year follow-up, the tumor became symptomatic (partial and generalized seizures). The CT scan and nuclear magnetic resonance imaging revealed an increased size of the mural tumor and the development of a cystic component. Multi-beam irradiation of the tumor (dose of 30 Gy at the center with 21 Gy on the isodose 70%) was performed with a LINAC for radiosurgery coupling a modified Saturne 18 MeV linear accelerator and a Talairach stereotactic frame. Following multi-beam irradiation, the increase in size of the cyst imposed further intracavitary radiation using Rhenium 186 (186Re) to deliver 400 Gy to the cyst wall. After a period of intense cerebral edema, resolutive with steroid treatment, we obtained progressive cyst disappearance and mural nodule retraction. A PET scan, performed 3 years after this treatment, revealed no metabolic activity in the persistent mural nodule. The patient remains totally asymptomatic.