Clinical Analysis of Gamma Knife Radiosurgery for Brain Metastases

ABSTRACT

Brain metastases from systemic cancer remains a significant source of morbidity and mortality. The clinical results of gamma knife radiosurgery for brain metastases are analyzed to identify treatment parameters and ascertain effectiveness correlated with local tumor control. Between May 1990 and August 1993, 103 patients with brain metastases were treated with gamma knife radiosurgery. Forty four patients had single metastasis. But the rest of the patients had multiple brain metastases: two lesions in 22 patients, three lesions in 13 patients, and more than four lesions in 24 patients. They were expected to survive more than three months and their Karnofsky performance scores were 70% or more. Fifty nine patients underwent radiosurgery only. Seventeen patients had received adjuvant whole brain radiotherapy(WBRT) with radiosurgery. Among 27 patients who underwent tumor resection and radiosurgery, 10 patients had received combined WBRT also. Despite of 91.6% of local tumor control, overall median survival was 9 months. Local recurrence rate was 8% but 30% of the patients were proved to distant recurrence. Combined radiotherapy and radiosurgery are not documented to improve local tumor control and survival. Gamma knife radiosurgery is shown to be effective and safe in controlling brain metastases. Further investigation is necessary to define optimal treatment parameters for radiosurgery.