RTHP-01. PENTOXIFYLLINE AND VITAMIN E FOR THE TREATMENT OF RADIATION NECROSIS AFTER STEREOTACTIC RADIOSURGERY

Abstract

BACKGROUND: The combination of oral pentoxifylline (Ptx) and vitamin E (VitE) has been used to treat radiation-induced fibrosis and soft tissue injury. A 2008 study showed an average decrease in edema with the use of Ptx + VitE in 11 patients with suspected radiation necrosis after stereotactic radiosurgery (SRS). Here we review outcomes in patients prescribed Ptx + VitE at our institution for the treatment of radiation necrosis. METHODS: 48 patients were included in this analysis. All patients were treated with SRS, had evidence of radiation necrosis, and had MR imaging before and after starting Ptx + VitE. The radiation oncologist’s impression of the imaging in the electronic medical record was used to score response to treatment. Official radiology reports were also reviewed. RESULTS: 43.8% of patients showed evidence of improvement, 18.8% showed no change, and 25% showed worsening radiation necrosis on imaging after starting Ptx + VitE. One patient had a mixed response; 5 patients (10.4%) had disease progression. The median time to response assessment after starting Ptx + Vit E was 3.17 months. 9 patients progressed significantly on Ptx + VitE and required Bevacizumab, hyperbaric oxygen therapy or surgery. Patients who had multiple lesions treated with SRS were less likely to show improvement on imaging after Ptx + VitE (p=0.037). 34 patients were also prescribed dexamethasone, either before (7), with (16), or after starting (11) Ptx + VitE. Use of dexamethasone was not associated with improved response to Ptx + VitE (p=0.471). 3 patients stopped Ptx + VitE due to reported side effects. CONCLUSION: Ptx + VitE appears safe for the treatment of radiation necrosis, but randomized data are needed to assess efficacy