Photodynamic therapy for recurrent supratentorial gliomas

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Abstract
We have used photodynamic therapy (PDT) in the treatment of 56 patients with recurrent supratentorial gliomas who had failed radiation therapy and who were candidates for palliative reoperation. There were 34 males and 22 females; their mean age was 41 years and the mean Karnofsky score was 79. Thirty-two patients had glioblastoma multiforme (GBM), 14 had malignant astrocytoma (MA), 6 had malignant mixed glioma (MM), and 4 had ependymoma (EP). Porphyrin photosensitizer was administered intravenously (i.v.) 12–36 hours prior to photoillumination. All patients had the recurrent tumor sub-totally resected or cyst drained at surgery followed by intraoperative cavitary photoillumination. In 15 cases interstitial photoillumination using fibers with 2 cm diffusing tips supplemented the cavitary illumination. The total light energy delivered ranged from 440 to 4,500 Joules (J) (median = 1,800 J). The energy administered ranged from 120 to 150 J per fiber and the linear energy density ranged from 65 to 450 J/cm. The energy density ranged from 8 to 110 J/cm2 (median = 38 J/cm2). There were two postoperative deaths and three patients were left with a persistent increase in their postoperative neurological deficit. The post-PDT median survival of patients with recurrent GBM was 30 weeks with a 1- and 2-year actuarial survival of 18% and 0%, respectively. The median survival of patients with recurrent GBM from first diagnosis was 118 weeks with a 1- and 2-year actuarial survival of 82% and 57%, respectively. The post-PDT median survival of patients with recurrent MA was 44 weeks with a 1- and 2-year actuarial survival of 43% and 36%, respectively. The median survival of patients with recurrent MA from first diagnosis was 147 weeks with a 1- and 2-year actuarial survival of 86% and 71%, respectively. Patients with MA who received more than the median light dose had a longer survival than those who received less than the median light dose. Recurrent malignant gliomas have a very poor prognosis. PDT is a successful palliative treatment when they recur and are amenable to further surgical treatment. With increasing light doses, better light delivery systems, and more effective photosensitizers further considerable improvement in survival can be expected.