Radiosurgery as part of the initial management of patients with malignant gliomas

Between May 1988 and May 1991, 41 patients with malignant gliomas were enrolled onto a prospective study designed to evaluate the role of radiosurgery as a component of initial management.

Thirty-seven patients underwent radiosurgery according to the protocol and were assessable for survival and complications of treatment. Diagnoses included glioblastoma multiforme (GBM) in 23 (62%) cases and anaplastic astrocytoma in 14 (38%) cases. In 20 (54%) cases, surgical resection was attempted initially, whereas 17 (46%) patients underwent biopsy only. Patients in the study group received external-beam radiotherapy that consisted of 5,940 cGy given in 33 fractions to partial brain fields that encompassed the primary tumor with a 3 to 4 cm margin. Radiosurgery, used as a technique for boosting the dose to any residual contrast-enhancing mass lesion, was given 2 to 4 weeks after the completion of conventional radiotherapy. Minimum radiosurgical doses ranged from 1,000 to 2,000 cGy (median, 1,200 cGy), whereas maximum doses ranged from 1,250 to 2,500 cGy (median, 1,500 cGy). The median tumor volume at the time of radiosurgery was 4.8 cm3 (range, 1.2 to 72 cm3). Adjuvant chemotherapy was not given.

After a median follow-up of 19 months, only nine of 37 (24%) patients have died. Six patients (all glioblastoma multiforme) died of recurrent tumor, whereas death was attributable to complications of treatment in two cases and intercurrent disease in one case. Four patients with recurrent tumor failed at the margins of the radiosurgical treatment volume, whereas two patients progressed locally. One patient is alive with local and marginal failure. Seven (19%) patients underwent reoperation at a median time of 5 months (range, 1 to 14 months) after radiosurgery.

We conclude that radiosurgery is a useful adjunct to other modalities in the initial management of patients with small, radiographically well-defined malignant gliomas.