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The prognostic impact of prior low
grade histology in patients with anaplastic gliomas: a case-control
study
EJ Dropcho and SJ Soong
Department of Neurology, Indiana
University Medical Center, Indianapolis 46202-5111, USA.
At the time of recurrence, the majority
of low-grade cerebral gliomas transform to a higher grade
of histologic malignancy.
The purpose of this study was to determine the survival
outcome for patients whose anaplastic gliomas began as
low-grade tumors compared with patients with de novo high-grade
gliomas.
Seventy-seven (11.5%) of 667 patients with anaplastic gliomas
consecutively treated at the University of Alabama at Birmingham had
histologically proven prior low-grade tumors.
As a group, the patients with prior low-grade tumors would
be expected to have a relatively favorable outcome, as they
were younger and had a lower proportion of glioblastoma
multiforme than the patients with de novo anaplastic gliomas.
The provide a valid comparison, we performed a matched case-control
study.
We matched 68 patients from the prior low- grade group one-to-one with
patients from de novo group for tumor histology, age, Karnofsky
performance scores, and type of surgery, without knowledge
of outcome.
The two groups received comparable radiotherapy and
chemotherapy.
For the 68 patients with prior low-grade tumor, median
actuarial survival from the time of diagnosis of malignant
degeneration was 19.7 months and the 5-year survival rate was 22%,
compared with 22.0 months and 28% for the 68 matched de novo patients.
Kaplan-Meier survival curves for the two group did not significantly
differ (p = 0.24 by logrank test).
There were no significant survival differences between the
patient subsets of prior low-grade versus de novo with glioblastoma,
anaplastic astrocytoma, or anaplastic oligodendroglioma/mixed anaplastic
glioma.
The data indicate that the currently available treatment options,
the survival outlook for patients with anaplastic gliomas, whose tumors
arose from transformation of low-grade gliomas, is equivalent to the
prognosis for patients with de novo anaplastic gliomas.
Copyright © 1996 by American
Academy of Neurology
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