The natural history of supratentorial hemispheric low-grade fibrillary astrocytomas is extremely variable. Although many patients survive 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 Hosital between January 1989 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 origination in the basal ganglia. thalamus. hypothalamus. optic pathways. and posterior fossa. Mixed gliomas were also excluded. survival rates were estimated by the method of Kapian-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 9median 32.9 years0. 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. Overall actuarial survival rates at 5, 1`0 years were 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 underwent additional resection of tumor. A dedifferentiation toward astrocytoma Grade 3 or 4 occurred in 2 of 6 patients (33.3%). The median time from
recurrence to
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 sharpness of the tumor border were confirmed by multivariate stepweise regression test.
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