Today’s radiation therapy technologies deliver precise treatment for patients with brain cancer.
The brain is part of the central nervous system. Fluid and the skull surround and protect it. Nerves carry messages from the brain to the rest of the body telling our muscles how to move and coordinate actions of our internal organs.
Malignant brain and spinal tumors are relatively rare compared to other cancer types. Tumors that spread to the brain from other locations (that are metastatic) are more common than those that begin in the brain. It is estimated that approximately 35,000 patients will be diagnosed with a primary brain tumor and 140,000 patients will develop brain metastasis each year. These tumors are slightly more prevalent in men than in women. Because they are located in such a critical area, spinal and brain cancers are complicated to treat and often involve a team of highly specialized clinicians.
Exposure to radiation and family history are the most common risk factors for brain cancer. Symptoms depend on tumor size, location and type. Pressure on a nerve or obstruction of fluid in the brain may cause the symptoms. The most common symptoms of brain tumors include headaches, nausea, vomiting, changes in hearing, speech or vision, difficulties with balance, problems with memory or numbness in the arms or legs.
Surgery, chemotherapy and radiation can all be effective against brain and spinal cancers. The location and stage of the tumor are critical factors in determining which therapy will be recommended.
Surgery is usually the first form of brain cancer treatment for brain cancer if the tumor is located in an accessible part of the brain. Through a craniotomy, or surgery through the skull, the neurosurgeon will remove as much of the tumor as safely possible and reduce the size of the target area of the cancer, thereby enhancing the effectiveness of subsequent radiation therapy. It is not typically an option when the tumor is located on a critical part of the brain that cannot be removed or if it is deep within the brain. Spinal cord tumors may or may not be operable for the same reasons.
Chemotherapy is occasionally used to treat metastatic brain and spinal cancers. In general, chemotherapy is not as effective as surgery or radiation therapy because it is difficult for the drugs to pass the blood-brain barrier. When chemotherapy is administered, it is typically done orally or intravenously after radiation therapy. In certain brain cancers, chemotherapy drugs may be administered by implanting thin wafers with the chemotherapy drugs directly into the brain that slowly dissolve over time. Alternatively, the drugs can be administered directly to the cerebrospinal fluid through a thin tube that is inserted through a small hole in the skull.
Highly advanced radiation delivery devices have made it possible to treat cancers of the brain and spine with millimeter precision. Typically, brain cancer radiation therapy is delivered after surgery to kill any tumor cells not removed by the surgery. If the tumor is an inoperable location, radiation alone may be used to treat the tumor.
Different forms of External Beam Radiation Therapy (EBRT) and Brachytherapy (also known as Internal Radiation Therapy) can be used to treat brain tumors.
There are several types of EBRT, including Three-dimensional Conformal Radiation Therapy (3D-Conformal), Intensity-Modulated Radiation Therapy (IMRT) and Stereotactic Radiosurgery (SRS). Occasionally Low Dose- Rate (LDR) Brachytherapy, sometimes called seeds, is used to treat brain tumors. Which technology your oncology team recommends depends on the type, location and stage of your cancer.
3D-Conformal Radiation Therapy and Intensity and Modulated Radiation Therapy are particularly effective on larger, less defined tumors of the brain and spinal cord. During 3D-Conformal treatments, a device called a “multi-leaf collimator” will shape the individual radiation beams to “conform” to your tumor according to the data and instructions it receives from the system computer. IMRT uses thousands of radiation “beamlets” from many different angles to deliver a single dose of radiation. The intensity of the “beamlets” can change during the treatment session to modulate the dose, so that the tumor receives a very precise high dose of radiation, while minimizing damage to surrounding, normal tissue.
Before each session, a Radiation Therapist will carefully position you on the treatment table using a body immobilizer for precise body placement. Image guidance will be used to confirm the location of the tumor before the therapy begins. During your treatment sessions, the radiation delivery system will revolve around you, delivering the radiation according to the plan set by your Radiation Oncologist. Each treatment session lasts from 10 to 30 minutes. Typically, you will be scheduled for five sessions a week for five to eight weeks. The sessions are pain-free and require no sedation so you can return to your normal activities right away.
Stereotactic Radiosurgery combines extremely accurate image-guided tumor targeting with exact patient positioning, allowing higher doses of radiation to be delivered in fewer treatment sessions. SRS is only used for small, well-defined tumors in the brain. If you are a candidate for SRS, you will typically have one to five treatment sessions rather than the standard five to eight weeks of traditional EBRT treatment. During each session, a Radiation Therapist will carefully position you on the treatment table using a head immobilizer for precise head placement. Image guidance will be used to confirm the location of the tumor before the therapy begins. The machines are very quiet and you will feel no pain during the session.
LDR or Seed Brachytherapy is occasionally used a brain cancer treatment. Small radioactive seeds, each the size of a rice grain, are implanted into the brain and release radiation over the course of several months. Eventually, they no longer emit radiation and can remain in the brain.