Durable response to bevacizumab in adults with recurrent pilocytic astrocytoma

BACKGROUND: Adult pilocytic astrocytomas are rare and highly vascular tumors. AIM: We hypothesized that they may be uniquely responsive to bevacizumab (BEV). PATIENTS: We present four adult patients with pathologically diagnosed WHO grade I pilocytic astrocytoma who had robust and durable responses to BEV at time of recurrence. Three patients developed radiographic changes on MRI, consistent with progressive disease based on response assessment in neuro-oncology criteria. Median time to recurrence was 8.5 months. METHODS: All patients were treated with six cycles of BEV for recurrence. RESULTS: At the end of treatment, all patients had achieved a clinical and radiographic response. Median follow-up time after BEV is 20.5 months. CONCLUSION: This suggests that BEV may have true antitumor activity in adult pilocytic astrocytomas and may be important for achieving durable disease control.