Abstract
We report long term follow-up of 3 adult patients with unresectable suprasellar pilocytic astrocytoma who developed symptomatic worsening of neuroimaging soon after intensity-modulated radiation therapy (IMRT) and were treated with a combination of temozolomide and bevacizumab. The median age was 52 years (range, 24–52); 2 patients were men. After biopsy, patients were treated in the newly diagnosed setting with IMRT (dosage range 5220–6000 cGY). Soon after completion of RT (mean, 13 weeks) they exhibited increases in contrast enhancing volume and perilesional edema. Two patients had diplopia and one had visual loss. Two patients were treated with dexamethasone (mean, 8 mg daily) with inadequate control of symptoms. Treatment for suspected tumor progression was initiated with temozolomide 150–200 mg/sq m/d for 5/28 days (12 cycles) and bevacizumab 5 mg/kg (mean, 31 doses; range 25–43). All patients had rapid improvement of symptoms and MR imaging. No patient has yet experienced tumor progression, with a mean progression free interval of 409 weeks (298–474). In glioblastoma, pseudoprogression usually occurs within 6 months of completion of chemoradiation and can respond to bevacizumab. In retrospect, given the temporal proximity to the completion of IMRT and the durability of the responses, it appears likely that these patients actually had pseudoprogression rather than true progression. We suspect that they actually responded to the bevacizumab component of the regimen. Bevacizumab appears to be effective for treatment of pseudoprogression in adult suprasellar pilocytic astrocytoma.