This report demonstrates the effectiveness of bevacizumab in two patients with recurrent PTPR where treatment with radiotherapy and surgery alone was not feasible. In the first patient, bevacizumab treatment led to complete remission upon bevacizumab therapy while prior treatment with intrathecal liposomal cytarabine and systemic temozolomide failed to show any relevant response. Since bevacizumab was given alongside repeat radiotherapy, a synergistic effect of bevacizumab and radiotherapy cannot be excluded. Since radiotherapy has not been shown to be of prognostic relevance based on a univariate analysis (Fauchon, Hasselblatt et al. 2013), a putative synergistic effect of radiotherapy and bevacizumab might not play a crucial role in explaining the observed response. Following the surprising response with the first patient, we immediately went on to bevacizumab treatment. In this patient with bevacizumab monotherapy and without concomitant radiotherapy, partial remission was achieved. It should be noted that both patients developed deep vein thrombosis in the course of their disease. This has not been described before and should be given particular medical attention when treating patients with recurrent PTPR.
Our two cases are in line with a published case of recurrent PTPR treated with bevacizumab (Cohen, Salzman et al. 2013). The authors combined etoposide and bevacizumab after bevacizumab monotherapy failed after 13 months. In our report, the first patient was progression-free at least 16 months from bevacizumab treatment onset, while the second patient was progression-free for at least 7 months. Altogether, these findings indicate that bevacizumab may be a reasonable alternative in recurrent PTPR. To confirm our findings, a prospective and controlled study is needed.