Background: A reliable marker for tumor oligodendroglial cells is not
yet available, so that the histological recognition of the tumor still
encounters uncertainties. There is no general agreement also on progn
ostic factors in oligodendroglioma. The inconsistency concerns mainly
the histopathological factors. The aim of the study was recognition of
prognostic factors in oligodendroglioma. Methods: In a series of nine
ty-eight oligodendrogliomas, including twenty mixed oligoastrocytomas,
clinical [sex, age at surgery, tumor location, symptoms at presentati
on], therapeutic [extent of resection, year of surgery, post-operative
Karnofsky score, post-operative radiotherapy, post-operative chemothe
rapy], histological [cell density, nuclear pleomorphism, vascular endo
thelial proliferation, necrosis, microcysts, mitoses, mitotic index (M
I), apoptosis, apoptotic index (AI)] and immunohistochemical parameter
s [MIB-1 and PCNA Labeling Indexes (LIs), staining for GFAP, positivit
y for p53] were correlated with survival in uni-and multivariate analy
sis in order to identify their prognostic significance. Results: Age a
t surgery, extent of surgical resection, year of surgery, post operati
ve Karnofsky score and MIB-1 LI were associated with survival in both
uni-and multivariate analysis. Location, symptoms at presentation, mit
oses, MI, AI, and PCNA LI showed a significant correlation with surviv
al in uni-but not in multivariate analysis. The twenty cases of oligoa
strocytomas did not show any difference in survival from pure oligoden
drogliomas. Conclusions: Some clinical and therapeutic factors togethe
r with MIB-1 LI play a prognostic role. MIB-1 LI is prognostic with a
cut off of 8%. Histology gives a limited contribution to the prognosis
. Oligoastrocytomas had the same outcome and prognostic factors as pur
e oligodendrogliomas.