A brain metastasis is a tumor that develops from cancer cells that have spread from other cancerous sites in the body to the brain, usually through the bloodstream.  A tumor that develops in the brain or surrounding tissues is referred to as a primary brain tumor, and by definition, not a brain metastasis.

Brain metastases occur in approximately 20-40% of patients with cancer. Up to 75% of afflicted patients have multiple lesions. Although the most common sources of brain metastases in adults include lung, breast, and skin (melanoma) cancers, the primary site or tissue origin of the metastases is unknown in up to 15% of patients.

Metastatic brain disease is a focal disease and local control of the tumor is needed for patient survival. The approach in the past has been to treat metastatic brain tumors as a whole brain disease with whole brain radiation therapy (WBRT). Because of poor local control of tumor growth when treated solely by whole brain radiation therapy, brain metastases in the past led to rapidly declining health and poor outcomes. Most patients with brain metastases did not benefit from many advances in cancer therapy (immunotherapy, chemotherapy, conformal radiotherapy etc.) because these therapies don’t effectively reach brain metastases and individuals died quickly from the tumor's growth.

Brain tumor growth can be effectively controlled in most patients when a few intracranial metastases are present with cyberknife radiosurgery. 

Radiosurgery is an appealing substitute for open surgery in the treatment of brain metastases. It is non invasive, cost effective, safe and done as an outpatient procedure.

During the Cyberknife treatment, imaging cameras determine the actual location of the tumor. Each time the robotic arm repositions to deliver another treatment, the Cyberknife recalculates the true position of the tumor. The result is unsurpassed, submillimeter accuracy. Unlike the Gammaknife, there is no need for the stereotactic frame that the Gammaknife requires, overall treatment time is reduced, anesthesia is unnecessary and the process is completely painless and comfortable.  Because Cyberknife of Long Island does not use the invasive frame, treatment can be delivered over several visits, sparing healthy tissue and allowing for a better radiobiological result.