Brain Stem Gliomas
- Why do I need a team of doctors to treat my brain stem glioma?
- Can surgery help?
- What role does radiation therapy play in the treatment of brain stem tumors?
- What is the role of chemotherapy and other drugs?
- What is the role of chemotherapy in treating "atypical" brain stem tumors?
- What is a shunt operation, and why is it necessary?
- What are steroids, and how are they used?
Why do I need a team of doctors to treat my brain stem glioma?
Brain stem gliomas are relatively uncommon and require complex management. A child or adult with a BSG requires evaluation in a comprehensive cancer center where the doctors who have different areas of expertise can work together. This might include neurosurgeons, neurologists, oncologists, radiation oncologists, neuropathologists and neuroradiologists. Also because of the rarity of this disease, children and their families should be encouraged to participate in clinical trials in an attempt to improve and optimize therapy.
Can surgery help?
Surgery is usually not practical for typical brain stem gliomas. By their very nature, these tumors invade throughout the brain stem, growing and spreading between normal nerve cells. Aggressive surgery would cause severe damage to these nerve cells, which are vital for swallowing and breathing, arm, leg and eye movement.
For many atypical BSGs however, surgery with less than total removal can be performed. Surgery is particularly useful for tumors that grow out from the brain stem. Such surgery often results in quality long-term survival. Shunt placement (see explanation below) to treat pressure build-up is frequently necessary. Some of these tumors can be stable for many years without any treatment other than shunting.
What role does radiation therapy play in the treatment of brain stem tumors?
Radiotherapy limited to the involved area of tumor is the most common treatment for typical brain stem gliomas. Radiation administered daily over six weeks is standard. In some cases, twice-daily radiotherapy has been used to deliver higher dosages of radiation, but this technique has not improved survival for this disease.
What is the role of chemotherapy and other drugs?
The role of chemotherapy for typical brain stem gliomas is unclear. Up to the present, chemotherapy has been of little help, although efforts are underway to explore further the use of chemotherapy. Drugs used to increase the effect of radiotherapy have thus far shown no added benefit either. Immunotherapy using white blood cell hormones called interferons has also shown disappointing results. Finally, high-dose chemotherapy using the patient's own bone marrow or stem cells has so far shown little effect. Several adult and pediatric clinical trials of new immunotherapies and chemotherapies are underway.
What is the role of chemotherapy in treating "atypical" brain stem tumors?
In atypical brain stem tumors, chemotherapy has been useful in children whose tumors are progressive and not accessible via surgery. In children younger than age 3, chemotherapy may be preferable to radiotherapy because of the negative effect radiation can produce on the developing brain.
For recurrent or progressive brain stem gliomas a variety drug trials are available through the national research consortiums Children's Oncology Group and through many other institutions, including the Maxine Dunitz Neurosurgical Institute, Johns Hopkins Hospital and the National Institutes of Health/Children's National Medical Center.
What is a shunt operation, and why is it necessary?
About 50% of children and adults with BSGs will develop a pressure build-up in the head known as "obstructive hydrocephalus." This happens when cerebrospinal fluid gets trapped in the brain's ventricles. Shunts are simple mechanical tubing devices that divert this fluid to another location in the body, typically the abdomen where the fluid is absorbed through the tissues into the blood stream. Occasionally these children may be candidates for a procedure called third ventriculostomy, which may prevent the need for a shunt.
What are steroids, and how are they used?
Dexamethasone (trade name Decadron) is a steroid drug frequently administered to brain tumor patients to reduce the swelling and "tightness" caused by their tumors. This steroid is an extremely effective medicine to treat symptoms of swelling associated with a brain stem glioma, particularly following radiotherapy.
However, dexamethasone has a number of side effects that include mood changes, increased appetite and weight gain, fluid retention, blood sugar instability, high blood pressure and increased susceptibility to infection.
If you have been taking dexamethasone for more than a week or two, treatment must not be stopped suddenly. The dose must be gradually decreased, so that the body can readjust and resume its own normal production of steroids. If you are receiving dexamethasone, you should be given a schedule for decreasing the medication.
Adapted from Foer, DR and Fisher PG
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