Background: Stereotactic radiosurgery is being used with increasing frequency for the treatment of brain metastases. Optimal patient selection and treatment factors continue to be defined. This study provides outcome data from a single institutional experience with radiosurgery and identifies parameters that may be useful for the proper selection and treatment of patients.
Methods: Eighty-four patients underwent stereotactic radiosurgery for brain metastases between September 1989 and November 1995. Seventy-nine patients (93%) were treated at recurrence after previous whole brain radiotherapy. Patients had between 1 and 6 lesions treated with a median minimum tumor dose of 1600 centigrays (cGy). Thirty-eight patients (45%) had active extracranial disease at the time of radiosurgery.
Results: Median survival for the entire group was 43 weeks from the date of radiosurgery and 71 weeks from the original diagnosis of brain metastases. Patients with 1 or 2 metastases had significantly improved survival compared with patients with > or = 3 metastases (P = 0.02), and patients without active extracranial tumor survived longer than those with extracranial disease (P = 0.03). Median time to failure for 145 evaluable lesions was 35 weeks. Local control was significantly improved for radiosurgery doses of > 1800 cGy, and for melanoma histology.
Conclusions: These results are comparable to reports of patients treated with resection and significantly superior to results observed after whole brain radiotherapy. The authors conclude that stereotactic radiosurgery is an effective, low risk treatment for extending the survival of patients with recurrent brain metastasis. Although survival is best for patients with < or = two lesions and no active extracranial disease, selected patients with > two lesions or active extracranial tumor may benefit as well.