The CyberKnife System delivers high doses of radiation directly to brain tumors. The CyberKnife System offers patients a non-invasive alternative to brain cancer surgery, and can be used for brain tumors that are considered inoperable because of their location in the head, for those patients who cannot undergo brain cancer surgery due to their poor medical condition, or who refuse surgery. The CyberKnife System also can treat benign, or non-cancerous, tumors and other conditions, such as trigeminal neuralgia, arterialvenous malformations (AVMs), and menigioma.
CyberKnife brain cancer treatments are typically performed on an outpatient basis with one to three treatments, requiring no overnight hospital stays. Most patients experience minimal to no side effects with a quick recovery time.
Brain cancer is an abnormal growth of cells in the brain, which result in a collection of cells called a brain tumor. If the abnormal cells were originally brain cells that started to grow uncontrollably, it is a primary brain tumor. If the abnormal cells originated in another part of the body, such as the lung or breast, and were carried to the brain by the blood or other body fluid, then it is considered a metastatic brain tumor. More than 18,000 cases of primary brain tumors and more than 170,000 brain metastases are diagnosed in United States each year.
Primary brain tumors
There are many types of primary brain tumors, including meningiomas, pituitary adenomas, schwannomas and gliomas, which are divided into astrocytomas, ependymomas, medulloblastomas and oligodendrogliomas. Each primary brain tumor is categorized based on the type of normal brain cell from which they originated and has its own unique characteristics and growth patterns. Gliomas account for 40 percent of all primary brain tumors and it is not common for them to spread from the brain to other parts of the body. The most aggressive type of glioma is called glioblastoma multiforme.
Metastatic brain tumors
The cells that form metastatic brain tumors travel to the brain from other parts of the body through the bloodstream, along nerves or within the fluid surrounding the spinal cord and brain. These cells most commonly originate in tumors within the lung, breast, skin or colon, and are deposited in the brain where they grow into a tumor.
Both primary and metastatic brain tumors can be very dangerous because they can compress sensitive brain tissue and nerves within the head, causing patients to experience symptoms such as vision loss, hearing loss, difficulties with balance, pain or seizures. As these tumors grow larger, they can be life-threatening because they disrupt critical parts of the brain that are responsible for breathing and other basic life functions.
The treatment of brain tumors often requires combinations of several types of treatments to effectively fight the disease.
During the last 25 to 30 years, radiosurgery has emerged as an alternative to surgery. Unlike conventional radiation therapy, during which small doses of radiation are delivered over weeks and months, radiosurgery can treat a tumor in one to five sessions by delivering a high dose of radiation with extreme accuracy. During radiosurgery, hundreds of narrow radiation beams are delivered from different angles, all intersecting at the tumor. This treatment allows the tumor to be attacked by a high dose of radiation without damaging surrounding sensitive brain tissue. To be effective and safe, radiosurgery must be accurate. To achieve this accuracy, some radiosurgery devices, such as the Gamma Knife®, require a rigid stereotactic frame be affixed to a patient’s head so the system can pinpoint the exact location of a tumor. These frames are screwed into a patient’s skull after local anesthesia is given. Many patients find these frames to be uncomfortable and painful. In addition, patients may have to be hospitalized if they have multiple fractions
Other radiosurgery devices, such as the CyberKnife Robotic Radiosurgery System, improve on other radiosurgery techniques by eliminating the need for stereotactic frames. As a result, the CyberKnife System enables doctors to achieve a high level of accuracy in a non-invasive manner and allows patients to be treated on an outpatient basis.
For solitary tumors that are not near the brain’s most critical structures, such as those involved in vision or regulation of breathing, the most common treatment option is surgery, in which the tumor is cut out through surgery. Surgery is used for primary brain tumors, such as a GBM, as well as solitary brain metastases and benign tumors. Surgery is often followed by whole brain radiation therapy or partial brain radiation techniques to eliminate any microscopic bits of the tumor. In some cases, malignant brain tumors can be treated in combination with chemotherapy for greater effect.
External beam radiation therapy is a common treatment for primary and metastatic brain tumors. Treatment for primary brain tumors is typically done over a 5-7 week period. The tumor volume is planned by a 3-D technique ensuring precise treatment to the tumor volume. Metastatic brain cancer is treated over a 2-3 week time frame. Generally the area being treated is larger to encompass the entire brain.
Chemotherapy medication is delivered orally or through an IV. It affects both normal tissue and the cancer cells, so patients may experience side effects, such as severe nausea and vomiting, infections, fatigue and weight loss. Chemotherapy is typically given to a patient in combination with other types of brain cancer treatment. For example, it may be given after whole brain radiation therapy to target both the metastatic tumors in the brain and the tissues outside the brain that originally produced the cancer cells.