Radiosurgery followed by planned observation in patients with one to three brain metastases

OBJECTIVE: To analyze the role of radiosurgery alone in patients with brain metastases. There were three specific study goals: 1) to determine whether survival of patients selected for this treatment approach can, be predicted successfully by use of the recursive partitioning analysis classification defined by the Radiation Therapy Oncology Group; 2) to evaluate local control; and 3) to identify risk factors of cerebral failure. METHODS: A total of 101 patients with Karnofsky Performance Scale scores of at least 50 and up to three brain metastases, each 3 cm or less in maximum diameter, were treated with radiosurgery alone. Survival, local control, distant brain freedom from progression (FFP), and overall brain FFP were evaluated according the method of Kaplan and Meier. Risk factors for survival and overall brain FFP were analyzed using the Cox model. RESULTS: Median survival was 13.4 months, 9.3 months, and 1.5 months for patients in recursive partitioning analysis Classes 1, 2, and 3, respectively (P < 0.0001). At 1 year, local control, distant brain FFP, and overall brain FFP were 91, 53, and 51%, respectively. An interval greater than 2 years between diagnosis of the primary tumor and diagnosis of brain metastases and the presence of a single brain metastasis were associated with significantly higher overall brain FFP. CONCLUSION: Recursive partitioning analysis classification successfully predicted survival. Radiosurgery alone yielded high local control. Overall brain FFP was highest in patients with an interval greater than 2 years between primary diagnosis and diagnosis of a single brain metastasis.