Grade II oligodendrogliomas are rare
and slow growing tumors, making long-term follow up difficult, but necessary
for better understanding. In this retrospective study a review of all grade II
oligodendrogliomas encountered in the last 20 years at one institution, was
undertaken to determine if specific tumor location and immunohistochemical
analysis had any impact on recurrence rate, progression free survival, or life
expectancy. Eighty-nine grade II oligodendroglioms cases were reviewed (38
females and 51 males; mean age was 40.3 ± 13.8 years). Tumor location was:
frontal lobe (44, 49.4%) and superior frontal gyrus (30, 33.7%). 1p19q data
were available in 49 patients. Twenty-nine cases were co-deleted (59.2%). There
was no significant difference in the incidence of 1p19q co-deletion between
superior frontal gyrus tumors vs. other frontal tumors or extra-frontal tumors (p = 0.45). Follow up of at least
3 months after diagnosis was available in 79 patients (mean follow up: 93.2
months). In recurrence analysis, recurrence by 1p19q status and recurrence by
location revealed no significant differences. In analysis of progression,
progression by 1p19q status and progression by location revealed no significant
differences. An analysis of deaths for the sample, deaths by 1p19q status and
deaths by location revealed no significant differences. There was a higher
death rate among patients >50 years of age, however this, too, was not
significant. There did not appear to be any advantage in recurrence rate,
progression free survival, or life expectancy for tumors located in the frontal
lobe or superior frontal gyrus. 1p19q co-deletion did not appear to confer an
advantage as measured by time to recurrence, time to progression, or overall
survival. Other than age, eloquent location, Karnofsky status, and overall
tumor size as reported by others, tumor location and 1p19q status in low grade
oligodendrogliomas are not currently predictive of survival.