Also see, Conditions We Treat, Brain Cancer.

What are common types of brain tumors?

The majority of brain tumors are actually metastases from a primary tumor outside the brain. Malignant cancer cells can spread to the brain from a tumor in the lung, colon, or stomach, for example. Tumors that originate in the brain are called primary brain tumors. Common primary brain tumors arise from the cells that surround and support nerve cells, called glial cells. These tumors are called gliomas. Another common type of primary brain tumor arises from cells that form the meninges, the protective membrane surrounding the brain, and is called meningioma. Other types of primary brain tumors include pituitary tumors and lymphomas.

What causes brain tumors?

Most brain tumors are metastases from cancers in other parts of the body. The cause of primary brain tumors is not well understood in most cases. Some individuals are at higher risk of developing primary brain tumors. For example, patients with weakened immune systems are at increased risk of developing lymphoma of the brain. Certain hereditary conditions such as neurofibromatosis are associated with increased risk of brain tumors. Children treated with brain radiation for leukemia have been found to have a higher than average risk of developing brain tumors later on as adults.

Do cell phones cause brain tumors?

Cell phone use has been extensively studied as a risk factor for developing brain tumors. The literature is not conclusive, with some studies showing no increase in risk, and other reports showing an association with cumulative lifetime cell phone use. While cell phones do not give off high-energy ionizing radiation that can directly damage brain cells, there continues to be concern given the many hours of exposure and the increasingly young age of users. In light of this unresolved question, some experts advocate using an earpiece to keep the transmitting antenna housed in phone away from the head.

How are brain tumors evaluated?

Important parts of the evaluation of brain tumors include the patient history (including specific symptoms involved, duration of symptoms, and the presence of seizures), and neurologic examination. Imaging studies are obtained to show the location of the lesion and its relationship to critical areas of the brain. Often, a team of specialists including neurologists, neurosurgeons, neuroradiologists, radiation oncologists and medical oncologists will discuss a case and jointly determine an appropriate treatment plan.

How are brain tumors treated?

Most primary brain tumors are initially considered for surgical resection. Depending on both tumor factors such as location, and patient factors such as general medical condition, surgery may or may not be feasible. Radiation and chemotherapy can be used after surgery to treat tumor cells in the surgical site, or in cases where surgery is not performed. Metastatic tumors can also be treated with surgery, radiation therapy, and chemotherapy, often in combination.

How is radiation used to treat brain tumors?

There are two basic types of radiation treatment: conventional external-beam radiation treats larger regions of the brain or even the whole brain, whereas radiosurgery focuses radiation to small specific targets in the brain. The newest type of conventional treatment uses a technique called intensity-modulated radiation therapy (IMRT), which allows shaping of radiation dose to avoid critical structures while covering the target lesion. Radiosurgery techniques include Gamma Knife, Cyberknife, and Novalis treatments. Malignant primary brain tumors are usually treated with conventional radiation to cover areas of the brain adjacent to the visible tumor that may harbor cancer cells. Depending on the type and number of brain metastases, patients may undergo surgery, radiosurgery, or whole brain irradiation, or some combination of these treatments. Benign tumors are often treated surgically or with radiosurgery.

What is the difference between Gamma Knife, Cyberknife, and Novalis treatment?

All three of these machines can perform radiosurgery (the precise, targeted delivery of high dose radiation to a small lesion in the brain). The Gamma Knife system focuses a minimum of 201 fixed radiation beams onto the target, while the Cyberknife system uses a robotic arm to position a small linear accelerator to deliver multiple (typically 80 to 150) beams directed to the lesion. The Novalis relies upon fixed beams or arcs of continuous therapy to deliver dose to the target. The machines differ in a few respects, namely the use of a fixed head frame with Gamma Knife versus a mask with the Cyberknife or Novalis; the ability of Cyberknife and Novalis to give more than one fraction (typically three to five) of radiation; and the ability of the Cyberknife and Novalis to also treat lesions in the rest of the body.

What about proton beam treatment?

Proton centers have been around since the 1950’s. While proton beams are equivalent in terms of biological effect to photon (x-ray) beams and are a type of radiation, there are differences in the physical characteristics of these beams. Proton beams can be used to deliver radiation to targets near a critical structure, similar to the use of IMRT, Gamma Knife, or Cyberknife radiosurgery. There is no proven benefit of Proton therapy over any of these stereotactic machines in terms of tumor control or safety.

Also see, Conditions We Treat, Brain Cancer.

Additional resources on the web include:

National Brain Tumor Foundation
www.braintumor.org

International Radiosurgery Association
www.irsa.org

National Cancer Care Network
www.nccn.org