Object: Gliosarcoma, a rare malignancy of the central nervous system, consists of gliomatous and sarcomatous elements. There are conflicting reports regarding its aggressiveness and cell line of origin compared with those of glioblastoma multiforme (GBM). The goal of this study was to compare clinicopathological features such as disease-free survival time and actual survival time in patients with gliosarcoma with a matched group of patients with GBM as well as with the entire group of patients with GBM.
Methods: The authors report on 18 cases of gliosarcoma derived from a series of 748 Grade 4 astrocytoma cases that were part of four consecutive randomized Phase III trials conducted between 1979 and 1996. In this series the gliosarcoma group represented only 2.4% of all GBMs and included 11 men and seven women with a median age of 61.5 years (range 31-81 years). The median tumor size was 5 cm (range 2-8 cm). The locations, all supratentorial, included temporal in 44%, parietal in 28%, frontal in 17%, and occipital in 11%. The 18 patients with gliosarcomas, all Grade 4 (World Health Organization classification), were compared with the entire group of 730 patients with GBM and a control group of 18 patients with GBM matched for known prognostic factors including patient age, randomization date, performance status, extent of resection, and protocol number. Patients in all treatment groups received radiation and nitrosourea-based chemotherapy. The median time to progression and the median survival times for the patients with gliosarcoma were 28.0 and 35.1 weeks as compared with 24.7 and 41.6 weeks for the entire group of patients with GBM (log rank test, p = 0.94 and 0.27, respectively) and 16.7 and 34.4 weeks in the control group (p = 0.20 and 0.84, respectively). In previous molecular cytogenetic analyses of gliosarcoma these authors have shown similar genetic changes in the gliomatous and sarcomatous components.
Conclusions: The data obtained in this study support the conclusion that gliosarcoma shares significant clinical and genetic similarities with GBM and that the same principles should be applied for patient enrollment in research protocols and treatment for these two kinds of tumor.