Stereotactic radiosurgical treatment of brain metastasis of primary tumors that rarely metastasize to the central nervous system

We evaluated the local control of gamma knife stereotactic radiosurgery (GKSRS) in the treatment of cerebral metastases from primary tumors that rarely metastasize to the central nervous system (CNS). There is little published data on this subject with very few series on specific primary tumors. We present our experience treating these lesions with GKSRS combined with a review of the salient literature. A retrospective study of 36 patients who collectively underwent 44 GKSRS procedures for CNS metastatic disease was undertaken. Our series includes four patients with sarcoma, two with prostate cancer, three with thyroid cancer, five with endometrial cancer, seven with ovarian cancer, two with cervical cancer, six with esophageal cancer, two with bladder cancer, one with liver cancer, one with pancreatic cancer, and three with testicular cancer. With 44 gamma knife sessions treating 74 tumors, 63 tumors showed no radiographic evidence of progression, and 13 tumors demonstrated radiographic progression between one and 12 months after gamma knife treatment. In six patients in the population, further treatment with GKSRS was necessary due to enlargement of untreated lesions or new metastatic disease. GKSRS for uncommon CNS metastases is appears to be efficacious in controlling the treated tumor. The majority of tumors treated in our study did not progress post gamma knife.