Long-sustaining response in a patient with non-resectable, distant recurrence of glioblastoma multiforme treated by interstitial photodynamic therapy using 5-ALA: case report

Glioblastoma multiforme continues to be a devastating disease despite modest improvements in survival achieved at present, and there is an urgent need for innovative treatment concepts. Five-aminolevulinic acid (ALA) is a drug which induces protoporphyrin IX accumulation in malignant gliomas and has been explored for fluorescence-guided resections of these tumors. ALA is also under investigation as a photosensitizer. We report a case of a patient with prior left frontal glioblastoma multiforme treated by surgery, radiation and chemotherapy, who developed a remote lesion in the left insula, which was refractory to secondary treatments. In a compassionate use setting she was treated by oral application of ALA (20 mg/kg bodyweight), and stereotactic phototherapy achieved by positioning four laser diffusors using 3-dimensional irradiation planning, and a 633 nm diode laser. The lesion disappeared 24 h after therapy. Circumferential contrast enhancement was observed at 72 h, which disappeared in the course of subsequential months. Edema resolved completely. The patient is still free of recurrence 56 months after treatment, demonstrating an impressive and long-lasting response to this novel mode of therapy.