Purpose: To conduct a Phase II one-arm study to evaluate the long-term efficacy and safety of accelerated fractionated radiotherapy combined with i.v. carboplatin for patients with previously untreated anaplastic gliomas.
Methods and materials: Between 1988 and 1992, 90 patients received 1.9-2.0-Gy radiation 3 times a day with 2-h infusions of 33 g/m(2) carboplatin for two 5-day cycles separated by 2 weeks. After radiotherapy, patients received procarbazine, lomustine (CCNU), and vincristine (PCV) for 1 year or until the tumor progressed.
Results: Ninety patients were evaluable for analysis. Histologically, 69 had anaplastic astrocytoma; 14, anaplastic oligoastrocytoma; and 7, anaplastic oligodendroglioma. Gross total resection was performed in 20 (22%), subtotal resection in 45 (50%), and biopsy in 25 (28%); reoperation (total or subtotal resection) was performed in 50 (56%) patients. A multivariate analysis showed that a younger age (p = 0.026), Karnofsky performance score (KPS; p = 0.009), and brain necrosis (p = 0.0002) were predictive of a better survival. Results from analysis of extent of surgery (biopsy, subtotal resection, gross total resection) approached significance (p = 0.058). Radiation dose, irradiated tumor volume, and techniques used (boost and fields) were not significant variables. The median survival (MS) of all anaplastic glioma patients was 28.1 months; for anaplastic astrocytoma patients, MS was 28.7 months and 40.8 months for the combined anaplastic oligodendroglioma/oligoastrocytoma patients. Long-term survival occurred in 25% of anaplastic glioma patients who were alive 8.6 years after treatment was initiated. Treatment-induced necrosis was documented by surgery or autopsy in 19 (21%) patients; 21 (23%) had a mixed pattern of necrosis and tumor; and an additional 13 (14%) patients who did not have surgical or autopsy demonstration of predominant radiation necrosis had magnetic resonance imaging (MRI) evidence of radiation necrosis. Serious clinical neurologic deterioration and/or dementia requiring full-time caregiver attention were observed in 9 (10%) patients.
Conclusion: When comparable selection criteria are applied, the rate of MS in this study is inferior to results attainable with current radiation and chemotherapy approaches, although the rates of long-term survival are comparable. Theoretically, patients failing therapy and dying earlier than anticipated may be because of excessive central nervous system (CNS) toxicity resulting from the combination of accelerated fractionated irradiation, intensive carboplatin chemotherapy before each radiation fraction, and postirradiation PCV chemotherapy. On the other hand, patients with treatment-induced necrosis survived significantly longer than patients who did not demonstrate MRI or histologic evidence of necrosis (MS, 106 months vs. 18-33 months).