Prognosis of Cerebellar Glioblastomas: Correlation Between Prognosis and Immunoreactivity for Epidermal Growth Factor Receptor Compared with Supratentorial Glioblastomas

Abstract

Background: Cerebellar glioblastomas (GBM) are rare tumors whose clinicopathological characteristics are not well understood. Patients and Methods: Clinico-immunohistochemical findings were retrospectively analyzed in 43 supratentorial- and 7 cerebellar GBM. The correlation between survival and immunopositivity for p53, epidermal growth factor receptor (EGFR) and Ki-67 in these tumors was statistically analyzed and compared. Results: Of the 43 patients with supratentorial GBM, 27 (62.8%) were EGFR immunopositive; their survival was significantly shorter than that of the 16 EGFR-negative patients (p=0.0248). There was no significant correlation between survival and p53 immunopositivity (p=0.7870) and Ki-67 labeling index (p=0.7133). All 5 cerebellar GBM patients treated with radio- and chemotherapy were EGFR-immunonegative; they survived significantly longer than patients with supratentorial GBM (p=0.0296) possibly because their EGFR negativity rendered their tumors more highly radiosensitive. Conclusion: The better prognosis of patients with cerebellar, EGFR-negative tumors compared to patients with supratentorial tumors is due to the higher radiosensitivity of these tumors.