Gamma-radiosurgery of intracranial gliomas

Follow-up results of various intracranial gliomas treated with radiosurgery are reported. Low-grade gliomas, astrocytoma GI, GII and oligodendroglioma demonstrated remarkable tumor shrinkage and tumor control after the treatment. In fact 83.3% of GI, 53.3% of GII astrocytomas and 80% of oligodendrogliomas demonstrated a shrinkage at the last follow-up. Complete remission was achieved in some cases with GI and GII astrocytomas, which seems to be curative since sufficient follow-up periods were obtained. In contrast malignant and infiltrating tumors like anaplastic astrocytomas and glioblastomas showed a far less favorable responses. One third of anaplastic astrocytomas and 10% of glioblastomas showed tumor shrinkage. Although central tumor necrosis were seen frequently after the treatment, tumor control could not be achieved at the periphery of high-grade gliomas. Rates of tumor control were 100% in GI, 80% in GII, 57% in GIII astrocytoma, 25% in glioblastomas and 80% in oligodendrogliomas respectively. These results indicate that only the localized tumors with benign biological behavior are indicated for radiosurgery so far. High-grade gliomas with highly infiltrative and malignant characters are not good candidate for radiosurgery and have to be treated with combined modalities including this treatment method. (author)