Gamma Knife Radiosurgery for Single & Multiple brain Metastasis

Metastatic brain tumors have been considered to be a good candidate for surgery because they are usually noninfiltrative to adjacent normal brain tissue and spherical in shape. These conditions meet the necessities for radiosurgery. Between May 1990 and Dec. 1994, 57 patients with metastatic tumors were treated radiosurgically using Leksell gamma unit at Asan Medical Center. Among 57 patients with metastatic brain tumors, 33 patients had 76 tumors that were followed-up clinically and radiographically. Sixty-two tumors disappeared or decreased in size and 8 tumors remained stable until 3 to 6 months after radiosurgery on CT or MRI scans. Local recurrence rate was 8% and tumor control rate was 92%. Median survival time was 15 months. New metastases were noted in 11 patients during follow-up periods. Gamma Knife radiosurgery appears to be the best therapeutic method for single and multiple brain metastases. The short hospitalization time and the benignity of the procedure are of special importance for patients with a short life expectancy.

Clinical Experience of Gamma Knife Rediosurgery for Acoustic Neurinomas

Microsurgical tumor removal is the treatment of choice to relieve the mass effect for the treatment of acoustic neurinoma patients. Gamma knife radiosurgery is another treatment option for patients with tumor size of less than approximately 4cm. Between May, 1990 and March, 1994, 55 tumor lesions from 50 patients were treated with gamma knife radiosurgery at Asan Medical Center. Following microsurgery, 20 patients underwent gamma knife radiosurgery for tumors not removed surgically. The remaining 30 patients underwent gamma knife radiosurgery alone. For an average follow-up period of 26 months(ranging from 6 to 45 months), 37 lesions out of 39 lesions responded, giving a tumor growth control rate of 94.9%. Facial neuropathy and trigeminal neuropathy were noted in 8% and 6%, respectively. According to these results, it is suggested that gamma knife radiosurgery in an effective altrnative therapeutic modality for the management of small to moderate sized acoustic neurinomas.