Gamma knife radiosurgery for patients with multiple cerebral metastases

Although efficacy of gamma knife radiosurgery has been demonstrated in numerous studies, the policies in patients with multiple metastases seem to be unequivocal. The maintained quality of life, the possibility of short hospitalization and the continuation of a systemic chemotherapy are increasingly important arguments in favor of a minimally invasive radiosurgical approach. These factors are particularly emphasized in patients with a dismal prognosis. The current retrospective analysis was undertaken to summarize the clinical results of radiosurgery in patients with multiple cerebral metastases of various primary cancer. Fractionated whole brain radiotherapy (WBRT) was omitted as prophylactic treatment and applied only in cases with general tumor spread. Clinical data of all consecutive patients (n = 215) who received gamma knife radiosurgery for cerebral metastases between January 2001 and January 2003 at the gamma knife Centers of the Karolinska Hospital and H.M. Queen Sophia Hospital (Sophiahemmet) Stockholm were analyzed retrospectively. 172 patients were treated for multiple metastases (198 treatments). The median prescription dose was 22 Gy (range 14-34 Gy). The Kaplan Meier plot shows a median survival (MST) of 7.8 months for patients with multiple cerebral metastases and 13.7 months for patients with single metastases. There was no relation between survival and number of metastases in patients with multiple metastases. Within this group 11.6% (20/172 patients) developed adverse radiation reactions. Tumor recurrences were documented by FDG-PET in 7 patients (out of 172 patients: 4.1%) after a median latency of 10 months after radiosurgery. In summary, gamma knife radiosurgery provides a highly effective and minimally invasive method to treat patients with multiple cerebral metastases even without prophylactic WBRT. Local control and patient survival in the present series of patients is in accordance with other retrospective series of patients with single and multiple metastases.