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Long-term outcome of low-grade
oligodendroglioma and mixed glioma
Jon D. Olson, MD,
Elyn Riedel, MA and Lisa M. DeAngelis, MD
From the Departments of Neurology
(Drs. Olson and DeAngelis) and Epidemiology and Biostatistics (E.
Riedel), Memorial Sloan-Kettering Cancer Center, New York, NY. Address
correspondence and reprint requests to Dr. Lisa M. DeAngelis,
Department of Neurology, Memorial Sloan-Kettering Cancer Center, 1275
York Avenue, New York, NY 10021. Received November 2, 1999. Accepted
in final form December 20, 1999.
Background. Low-grade
oligodendrogliomas and mixed gliomas can be indolent and
remain unchanged for years.
Optimal timing and effectiveness
of initial treatment is uncertain and therapy can be
associated with toxicity.
Methods. Retrospective
review of patients diagnosed between 1979 and 1997 with
low-grade oligodendroglioma or mixed glioma.
Time to progression, survival, prognostic factors, and treatment toxicities
were evaluated.
Results. A total of 106
patients (77 oligodendroglioma, 29 mixed glioma) were
identified; median age was 36.7 years.
Initial presenting symptoms were seizures in 76 (72%) and
headache in 11 (10%); tumor was diagnosed as an incidental
finding in five patients.
Tumor progression was diagnosed in 72 patients (68%).
Overall median time to progression (MTTP) was 5.0 years (range 0.5
to 14.2).
Median overall survival (OS) was 16.7 years.
No prognostic factors reached statistical
significance.
MTTP and OS were not significantly affected by
treatment.
Of 62 patients who received radiation therapy, 9 (15%)
developed radiation necrosis and 13 developed radiation
therapy–related cognitive changes, requiring
ventriculoperitoneal shunting in six.
Significant myelosuppression was seen in 35 of 76 (46%)
patients treated with chemotherapy.
Conclusions. Low-grade
oligodendroglioma and mixed glioma have a long median
overall survival.
There were no apparent differences in either immediate
versus deferred treatment or choice of initial therapy on
disease-free or overall survival.
Chemotherapy was associated with significant acute toxicity
in almost one half of patients; radiation therapy produced
late neurotoxicity in one third, justifying deferred
treatment until clinically necessary.
Key words: Oligodendroglioma, Mixed
glioma, Outcome, Chemotherapy, Radiation therapy
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