Surgery is the first step for the treatment of gliomaa, as it provides two important benefits: First, it procures tumor tissue to establish a diagnosis. Secondly, it offers the possibility to remove as much tumor is safely possible to relieve mass effect, reduce swelling and facilitate response to adjuvant therapies, when indicated. The decision whether to perform a simple biopsy or a full resection depends on multiple factors, but particularly on the clinical and medical conditions of the patient, as well as the predicted extent of resectability of the tumor.
Important tools to maximize efficiency and safety of surgery are:
- Neuronavigation: it is, in essence, a GPS system for the brain, and allows the surgeon to visualize in real time on the MRI his/her localization within the patient’s brain. This significantly increases precision and minimizes the risk of injuring normal brain.
- Awake surgery: This technique is particularly useful to resect tumors located in speech areas, and also when close to primary motor cortex bilaterally. The patient is kept sedated but not intubated, so that he/she can speak and execute commands when asked to. In this way, the surgeon can continuously asses the patient’s functions while removing the tumor.
- Motor mapping during general anesthesia: The regions of the brain controlling movement can be also stimulated with an electrode even if the patient is asleep. A stimulator is used to apply currents directly to the brain cortex, and muscle responses are recorded. Positive responses are interpreted as brain structures that should be spared from resection.
- Fluorescent dyes: Tumors, particularly those of higher grade, have the characteristic to avidly absorb certain dyes that are given IV to the patient just before surgery. In this way, the tumor tissue becomes colored by the specific dye, while the normal brain does not. This allows a much more precise definition of what should be resected and what should be left untouched. Among the most reliable dyes are 5-ALA, which colors the tumor violet, and Fluoresceine, which colors the tumor yellow, when visualized with appropriate lenses.
Chemotherapy uses drugs to kill tumor cells. Chemotherapy drugs can be taken in pill form (orally) or injected into a vein (intravenously).
Chemotherapy is usually used in combination with radiation therapy to treat gliomas. The chemotherapy drug used most often to treat gliomas is temozolomide (Temodar), which is taken as a pill.
Side effects of chemotherapy depend on the type and dose of drugs you receive. Common side effects include nausea and vomiting, headache, hair loss, fever, and weakness. Some side effects may be managed with medication.
Radiation therapy usually follows surgery in treatment of glioma, especially high-grade gliomas. Radiation uses high-energy beams, such as X-rays or protons, to kill tumor cells. Radiation therapy for glioma comes from a machine outside your body (external beam radiation).
There are several types of external beam radiation currently used and under study for the treatment of glioma. The type of glioma you have, its grade and other prognostic factors are considered in determining the timing and type of radiation therapy you may receive. A doctor who specializes in radiation therapy for cancer (radiation oncologist) will work closely with your other doctors to plan and coordinate the most appropriate radiation treatment for you.
Radiation therapy options include:
- Using computers to pinpoint delivery of radiation treatment to the exact location of the brain tumor. Techniques include intensity-modulated radiation therapy and 3D conformal radiation therapy.
- Using protons — the positive parts of atoms — rather than X-rays as the source of radiation. This technique, called conformal proton beam therapy, delivers radiation only once proton beams reach the tumor, causing less damage than X-rays to surrounding tissue.
- Using multiple beams of radiation to give a highly focused form of radiation treatment. While this technique is called stereotactic radiation therapy (radiosurgery), it doesn’t actually involve surgery in the traditional sense. Each beam of radiation isn’t particularly powerful, but the point where all the beams meet — at the brain tumor — receives a very large dose of radiation to kill the tumor cells in a very small area.
There are different types of technology used in radiosurgery to deliver radiation to treat brain tumors, such as a Gamma Knife or linear accelerator (LINAC).
Side effects of radiation therapy depend on the type and dose of radiation you receive. Common side effects during or immediately following radiation include fatigue, headaches and scalp irritation.
Steroid Dexamethasone is the preferred medication for alleviating symptoms related to brain swelling associated with the tumor. While highly effective in providing quick relief, it does not have a direct impact on the tumor. Prolonged use, beyond 2-3 weeks, may lead to notable side effects such as weight gain, elevated blood sugars, hypertension, increased infection risk, and irritability.
