Survival and Prognostic Factors of Supratentorial Hemispheric Low-grade Fibrillary Astrocytomas

Choi, Joong Uhn; Kim, Eun Young; Chung, Sang Sup; Lee, Kyu Chang

Abstract

The natural history of supratentorial hemispheric low-grade fibrillary astrocytomas is extremely variable. Although many patients wurvive for an extended period of time, other patients show a rapidly progressive course and early death. In an effort to clarify the natural history and prognostic factors, we conducted a retrospective study. Of 49 patients treated at Yonsei University Hospital between January 1980 and December 1991 for histologically confirmed low-grade fibrillary astrocytomas of cerebral hemisphere, 46 patients were followed for more than 30 months. Pilocytic and gemistocytic astrocytomas were excluded, as were tumors originating in the basal ganglia, thalamus, hypothalamus, optic path-ways, and posterior fossa. Mixed gliomas were also excluded. Survival rates were estimated by the method of Kaplan-Meir. The prognostic factors were analyzed by log-rank test and Cox stepweise multiple regression test for multivariates. The 46 patients consisted of 31 males and 14 females who ranged in age from 6 to 64 years(median 32.9 years). The median symptom duration before diagnosis was 10 months(1-120 months). Frontal lobe was the most common site of involvement and 70% of patients presented with seizure Ten(21.7%) cases were surface(gyral) type and 36 were located mainly in the deep white matter. Gross total removal was performed in 11 patients(24%), and 29 patients(63%) received postoperative irradiation. Overal actuarial survival rates at 5, 10 years ere 59%, 54%, respectively. Five-year progression-free survival was 52.7%. Of 16 patients with recurrence or progression of tumor with a median time to recurrence of 29 months, 6 undersent additional resection ot tumor. A dedifferentiation toward astrocytoma Grade 3 or 4 occurred in 2 of 6 patients(33.3%). The median time from recurrence ot death was 8 months. Younger age(<30 years), long symptom duration(>8 months), normal preoperative mental status, a history of preoperative seizure, the presence of cyst, well-defined tumor margin, and no extension into the corpus callusum or contralateal hemisphere were associated with a better prognosis on univariate analysis. Among 7 good prognostic factors, the significance of preoperative mental status and sharpeness of the tumor border were confirmed by multivariate stepweise regression test.