Bevacizumab Use in Refractory Adult Pilocytic Astrocytoma: A Single-Center Case Series

Pilocytic astrocytomas (PA) are highly vascular tumors with vascular endothelial growth factor (VEGF)-vascular endothelial growth factor receptor-2 (VEGFR-2) signaling present in the tumor vasculature. PA may, therefore, be responsive to VEGF blockade with bevacizumab (BEV). Data regarding the use of BEV in refractory PA in adults are limited primarily to case reports and case series of patients with recurrent PA. We conducted a single-center, retrospective cohort study from 2009 to 2018. We screened 426 patients with pathologically confirmed PA. We identified 5 adult patients with PA who received BEV at our institution with sufficient clinical follow-up to derive evidence of the efficacy and toxicity. All 5 patients experienced tumor progression after initial therapies which included surgery, radiation, and chemotherapy. Four patients received BEV as monotherapy, whereas 1 received BEV with the continuation of previously initiated alkylating chemotherapy (temozolomide). The average duration of BEV therapy was 10.2 months (range, 1 to 20 mo) with an average follow-up of 47 months (range, 6 to 112 mo). One patient had a severe necrotizing rash in areas of skin contact and discontinued after 1 cycle of BEV. All patients had stabilization per RANO criteria, with 1 patient experiencing progression after 10 months on treatment. One patient had disease progression 5 years after completion of BEV, but the tumor responded to repeat treatment with BEV. Our institution's experience with the use of BEV in recurrent PA is in line with previous reports of therapeutic benefit in recurrent adult PA.