CyberKnife Therapy - How Effective Is It?

Brain metastases from systemic cancer are the most common type of intracranial neoplasm in adults, being almost 10 times more common than primary malignant brain tumors, which cause a significant burden on the management of patients with advanced cancer (1). The lungs represent one of the most frequent sources of metastases to the brain, with a probability of (36–64%) (3). Symptoms suffered by the patients include headaches, epilepsy, focal weakness, numbness or changes in mental status. The prognosis of patients with brain metastases is not optimistic and the median survival time is ∼1–2 months if left untreated. The 1-year survival rate has been recorded as 10.4% (4,5). The treatment of metastatic brain tumors is complex; not only due to being able to provide local control and improve neurological function, but also due to factors such as age, performance and systemic disease status and the size, volume, location and number of metastases at presentation

CyberKnife is a robotic radiosurgery system with a linear particle accelerator (linac), which is coupled with real-time imaging to track and compensate for the patient’s or target’s motion. As a relatively non-invasive treatment modality, CyberKnife demonstrates certain benefits, including a more accurate target localization and improved dose delivery for the management of metastatic brain tumors that allows higher biologically effective dose delivery without increased incidence of toxicity.

In the present case, the results for the treatment of multiple brain metastases after CyberKnife surgery with a 7–8 Gy marginal dose was promising. CyberKnife for metastatic brain tumors is an effective and safe method for reducing the marginal dose prescribed for multiple brain metastases and for minimizing the radiation-related neurotoxicities. In conclusion, CyberKnife, a focused, highly-targeted radiosurgery and fractionated radiotherapy is particularly useful for multiple brain metastases. CyberKnife provides the advantage of the management of local recurrence and a tolerable complication rate. Although the treatment of brain metastases has been performed with CyberKnife, the clinical significance and optimal dose fractionation scheme require further investigation.