Stereotactic radiosurgery using the Leksell Gamma Knife Perfexion unit in the management of patients with 10 or more brain metastases.

OBJECT: To better establish the role of stereotactic radiosurgery (SRS) in treating patients with 10 or more intracranial metastases, the authors assessed clinical outcomes and identified prognostic factors associated with survival and tumor control in patients who underwent radiosurgery using the Leksell Gamma Knife Perfexion (LGK PFX) unit.

METHODS: The authors retrospectively reviewed data in all patients who had undergone LGK PFX surgery to treat 10 or more brain metastases in a single session at the University of Pittsburgh. Posttreatment imaging studies were used to assess tumor response, and patient records were reviewed for clinical follow-up data. All data were collected by a neurosurgeon who had not participated in patient care.

RESULTS: Sixty-one patients with 10 or more brain metastases underwent SRS for the treatment of 806 tumors (mean 13.2 lesions). Seven patients (11.5%) had no previous therapy. Stereotactic radiosurgery was the sole prior treatment modality in 8 patients (13.1%), 22 (36.1%) underwent whole-brain radiation therapy (WBRT) only, and 16 (26.2%) had prior SRS and WBRT. The total treated tumor volume ranged from 0.14 to 40.21 cm(3), and the median radiation dose to the tumor margin was 16 Gy. The median survival following SRS for 10 or more brain metastases was 4 months, with improved survival in patients with fewer than 14 brain metastases, a nonmelanomatous primary tumor, controlled systemic disease, a better Karnofsky Performance Scale score, and a lower recursive partitioning analysis (RPA) class. Prior cerebral treatment did not influence survival. The median survival for a patient with fewer than 14 brain metastases, a nonmelanomatous primary tumor, and controlled systemic disease was 21.0 months. Sustained local tumor control was achieved in 81% of patients. Prior WBRT predicted the development of new adverse radiation effects.

CONCLUSIONS: Stereotactic radiosurgery safely and effectively treats intracranial disease with a high rate of local control in patients with 10 or more brain metastases. In patients with fewer metastases, a nonmelanomatous primary lesion, controlled systemic disease, and a low RPA class, SRS may be most valuable. In selected patients, it can be considered as first-line treatment.