Diagnosis & Treatment

Radiation therapy uses high-energy x-rays or other types of ionizing radiation to stop cancer cells from dividing. It may be used when surgery is not advised, for tumors that cannot be completely resected, or after surgery to prevent or delay tumor recurrence. Radiation therapy can stop or slow the growth of inoperable tumors. Different forms of radiation are used for specific types and sizes of tumors. Use of radiation therapy is avoided in children below the age of three because it damages the developing brain.

Radiation therapy can be delivered by external or internal means. External beam radiation therapy involves linear accelerators and cobalt machines that direct radiation at the tumor from outside the patient’s body. Two of the main types of external beam radiation therapy are conventional and stereotactic radiosurgery.

Conventional radiation therapy delivers radiation to an entire region of the brain. The radiation is fractionated into many small doses and given over a period of time. The radiation is usually administered two to three weeks after surgery and continues for approximately six weeks (excluding weekends), with similar dosages at each visit. Depending on the location and size of the tumor(s), the treatment can be either focused or whole brain radiation therapy (WBRT). Focused radiation therapy aims x-rays at the tumor and area surrounding it. WBRT aims radiation at the entire brain. WBRT is used to treat multiple primary and metastatic brain tumors.

Interstitial radiation therapy (brachytherapy), an internal form of radiation therapy, involves surgically implanting radioactive material directly inside the tumor.

Stereotactic radiosurgery (SRS) provides pinpoint precision in the administering of radiation without any invasive surgery. During stereotactic radiation, a single, high dose of radiation is delivered to the tumor, minimizing damage to the surrounding brain tissue. Stereotactic radiosurgery is done on an outpatient basis. Patients typically receive just one treatment , but in some cases doctors may recommend up to five days in a row of the procedure.

In an SRS procedure, a head frame may be attached to the skull to hold the head completely still during the procedure. Some methods of SRS may use a mask instead of a head frame. Then CT or MRI scans are taken. With the aid of computer imaging, the location of the tumor is accurately calculated. The radiation is delivered directly to the tumor, often from several different directions. Size and location of the tumor are important eligibility criteria for SRS, and not everyone is a candidate.

You may hear different names associated with radiosurgery, including Gamma Knife®, LINAC, X-Knife®, Trilogy®, CyberKnife®, and Novalis®. These are the brand names of the equipment that doctors use to provide the treatment. The core principles are the same with each machine, but they use different sources of energy and different methods to target the tumor.

Chemotherapy uses chemicals (drugs) that have a toxic effect on tumor cells as they divide. The drugs interfere with the normal functioning of the rapidly dividing cells of the tumor to prevent tumor growth. Chemotherapy is usually a secondary therapy. It is usually not used for the treatment of noncancerous brain tumors.

Chemotherapy is usually taken orally or by injection, and may be given alone or in combination with other treatments. Chemotherapy is given in cycles, which consist of “on” and “off” phases – days of treatment followed by periods of time between treatments. Cycles vary depending on the drug or drugs used.

Another way to delivery chemotherapy to the brain is through polymer wafer implants. With this method, biodegradable wafers are saturated with a chemotherapy drug, BCNU, and placed directly inside the tumor cavity at the time of surgery. The wafers are left there to dissolve over a short period of time. In this way, a concentrated dose of BCNU (approximately 100 times higher than that tolerated through IV) can be delivered directly to the tumor site without increasing side effects.

Chemotherapy can decrease the chance of a brain tumor spreading outside the nervous system. Chemotherapy has been particularly effective in treating children with brain tumors that have spread outside the brain to the bone or bone marrow. The use of chemotherapy also helps delay or replace the use of radiation treatment in children, which can be harmful to the developing brain.

The medications most commonly prescribed for brain tumors are steroids for brain swelling (edema) and anti-epileptic drugs to control seizures.

Steroids (glucocortico-steroids) are drugs that reduce edema (swelling) in the brain. Steroids can help relieve pre-surgery symptoms, which may increase the time to make treatment decisions. Steroids may be prescribed at diagnosis, or before or after surgery. Common steroids include dexamethasone (Decadron), prednisone, and methylprednisolone. These drugs do not kill tumor cells, but can improve a patient’s condition. Steroids may be taken alone or combined with other forms of treatment. When the swelling is under control, then the dosage is gradually tapered off.

Steroids have a range of short- and long-term side effects. Common short-term side effects include insomnia, facial swelling and flushing, increased appetite, mood swings, and personality changes. Some people who take steroids for a few days or weeks do not experience side effects; others do. Side effects from long-term use of steroids, for example dexamethasone, may include cataracts, osteoporosis, muscle weakeness and diabetes. Patients should never stop taking steroids without the doctor’s knowledge. Instead, discuss possible side effects with the doctor.

Anti-epileptic drugs (AEDs) are medications used to control seizures. They are also called anticonvulsants, antiseizure drugs, and epilepsy drugs. A patient may be put on AEDs if he or she experiences a seizure or as a precautionary measure. Some common AEDs are phenytoin (Dilantin), carbamazepine (Tegretol), valproate (Depakote), levetiracetam (Keppra), gabapentin (Neurontin), topiramate (Topomax), and lamotrigine (Lamictal). The type and amount of medication is based on the level of seizure control needed and the side effects from the medication. Common side effects may include fatigue, weakness, nausea and lack of balance or coordination. A rash is an allergic reaction, and the patient must see a doctor immediately.

If the patient has not experienced seizures or if the person is seizure-free for an extended period of time, the AED may be tapered off. AEDs should never be stopped abruptly.It is important to remember that side effects of these AEDs vary greatly from person to person. If side effects are a serious problem, a doctor may change a patient’s medication.

Many medications will either increase or reduce the effect of AEDs. Some chemotherapy drugs may interact with AEDs and change the effectiveness of either or both drugs. Blood tests and other methods are used to monitor possible drug interactions.

To help your doctors recognize possible drug interactions, keep a list of all medications, including over-the-counter products. Also, keep track of symptoms that may be possible side effects.

A molecularly targeted therapy is a medication that blocks or inhibits an important cancer molecular abnormality, thus reducing the cancer’s destructive behavior

Molecular abnormalities are aspects of cells that are not normal. For example, these abnormalities control how cancer cells abnormally grow and divide; aggressively spread and invade; survive and live much longer than normal cells; and make new blood vessels (angiogenesis) required for tumor growth. Blocking abnormal molecules can lead to the death of cancer cells.

Molecularly targeted medicines are sometimes called “smart” medicines because of their ability to hone in on tumor cells while sparing healthy cells. The FDA has already approved several promising molecularly targeted therapies for patients with other types of cancer. These medicines are now being evaluated in clinical trials for brain tumor patients. Bevacizumab is one drug in particular that is being extensively evaluated in a number of studies.

Because these medications are specific to cancer cells, they have fewer side effects than traditional chemotherapy drugs. At some point in the future, doctors may be able to study each patient’s tumor in the laboratory and determine exactly which molecular abnormalities are present. With that information, the molecularly targeted therapy or regimen best suited to patient could be prescribed.

Complementary therapies are those that are not currently part of conventional medicine, but have demonstrated a favorable risk/benefit ratio to be used as part of supportive care. There are also alternative therapies, those which are promoted to be used in place of standard medical care. Together they are called CAM, for complementary and alternative medicine.

Some different types of complementary therapies include:

• Mind-body interventions: meditation, imagery, relaxation
• Biologically-based treatments: melatonin, herbals, mushrooms, high-dose vitamins, enzyme therapy, botanicals
• Manipulative and body-based approaches: massage, manipulation, chiropractics, yoga
• Energy therapies: Qigong, Reiki, therapeutic touch, distant healing
• Acupuncture

It is important to know that although complementary therapies can be a very helpful part of the overall cancer treatment plan, they can not cure cancer. On the other hand, patients should consider complementary therapies which empower them to take an active part in self care and help them go through cancer treatment. It is important that patients communicate with the health care team about any complementary therapies they are considering, as interactions may occur with standard treatments, such as chemotherapy.