3D Conformal Radiotherapy and Cisplatin for Recurrent Malignant Glioma

Abstract

To determine the maximum tolerated dose of 3D conformal radiotherapy in combination with Cisplatin for patients with recurrent malignant gliomas. From 1999-2003, nine patients with recurrent malignant glioma received fractionated radiotherapy and Cisplatin (20 mg/m2/d IV on days 1-5) in a Phase I radiation dose escalation trial. Three sequential dose levels were evaluated: 25 Gy, 30 Gy, and 35 Gy, using 5 Gy fractions. All patients received prior external beam radiation (median dose 59.4 (20-60) Gy) and five patients received prior chemotherapy. Six male and three female patients were enrolled with a median age of 52 years, and a median Karnofsky performance status score of 70. The median re-irradiated tumor volume was 18.9 (0.1-78.5) cm3 and the median follow-up was 8.8 (3.2-31.2) months. One patient (30 Gy/ 6 fractions) experienced medically reversible acute grade 3 toxicity. A second patient (35 Gy/ 7 fractions) experienced acute grade 2 toxicity and histology showed tumor and radiation effect. A third patient (25 Gy/ 5 fractions) experienced late grade 3 toxicity from radiation necrosis. The radiological responses consisted of complete response (1 patient), partial response (1 patient), and stable disease (2 patients). The median overall survival was 8.8 months (95% CI 8.0-9.9), and the median disease free interval was 2.0 months (95% CI 1.4-4.4). Seven patients received chemotherapy following re-irradiation and Cisplatin. The maximum tolerated dose of 3D conformal fractionated radiotherapy was 30 Gy in 6 fractions with low dose Cisplatin, which was well tolerated in terms of acute toxicity for our patient population. This regimen demonstrated only modest efficacy in the treatment of recurrent malignant glioma. Combinations of conformal re-irradiation and other systemic agents may merit investigation. Currently our recommended dose is 30 Gy in 6 fractions for selected patients.