INNV-29. PHOTODYNAMIC THERAPY FOR MALIGNANT BRAIN TUMORS

Abstract

Abstract INTRODUCTION Photodynamic therapy (PDT) uses the toxicity of singlet oxygen generated by a reaction between a photosensitizer in tumor cells and light with a specific wavelength. Recently, PDT for primary malignant brain tumors was approved in Japan. We retrospectively analyzed the patients treated with PDT in our hospital. METHODS From August 2017 to February 2019, total 16 patients were performed PDT in our hospital. After the tumor had been resected as extensively as possible, the region of probable tumor invasion in the resection cavity were irradiated superficially with a 664-nm diode laser for 180 sec (27 J/cm2) at a power density of 150 mW/cm. The characteristics of patients, the number of irradiation, adverse events, changes of the MR image, and clinical outcome were analyzed. RESULTS In histological examination, glioblastoma (GBM) were eleven cases, anaplastic oligodendroglioma were two cases, and other three cases were anaplastic astrocytoma, malignant meningioma, and malignant lymphoma. The mean tumor volume was 46.1 ml. Gross total resection, Subtotal resection, and partial resection were performed in 11 patients, 3 patents, and 2 patients, respectively. The mean number of laser irradiated sites was 15 (5~31 sites). Radiologically, the irradiated region indicated high intensity in diffusion-weighted image, which gradually disappeared for 2 weeks without neurological deterioration. In adverse events, venous congestion and brain swelling were observed in one patient. Three GBM patients were dead with tumor recurrence during a mean follow-up period of 24.4 months. CONCLUSION PDT was safe and useful for malignant brain tumors. However, PDT-induced specific changes in the tumor tissue should be monitored carefully.