Glioblastoma is the name given to a very aggressive, malignant tumor which arises from certain types of brain cells. It may also be referred to as a brain cancer, grade IV glioma or grade IV astrocytoma. There has been a growing understanding of the biology behind primary brain tumors. The use of molecular markers is playing an increasingly important role in defining the type, prognosis and probable response to treatment of these tumors. These markers identify mutations in the DNA of brain tumor cells as well as the molecular pathways they regulate.
Glioblastoma can develop as a new tumor, or a lower-grade glioma can transform into a glioblastoma over time.
Signs and Symptoms
Symptoms usually depend on the size and location of the tumor. Edema (swelling) around the glioblastoma will often increase symptoms.
Some of the more common symptoms associated with glioblastoma include:
- Nausea and vomiting
- Difficulty thinking
- Difficulty speaking
- Blurry vision
- Weakness on one side of the body
- Confusion, irritability or personality change
- Drowsiness or lethargy
Unhealthy changes (called mutations) in the DNA of brain tumor cells dangerously alter their normal life cycle and the way they function. Brain tumor cells replicate (make copies of themselves) uncontrollably. This even leads to the growth of new blood vessels, which provide the tumor with a supply of blood.
The cause of these DNA mutations is not fully understood. Some may be inherited or occur spontaneously. Exposure to high doses of ionizing radiation or chemicals called carcinogens may lead to the development of some mutations.
The presence of symptoms often leads to a physician visit. Diagnosis begins with the medical history and physical examination. Other tests are then used to establish the diagnosis and help guide treatment. These may include computerized tomography ( CT ) scan of the brain, magnetic resonance imaging ( MRI ) scan, functional MRI ( fMRI ), MRI perfusion scan and/or a positron emission tomography ( PET ) scan. CT is often the first test obtained. Use of a stereotactic biopsy may be indicated in certain situations.
A customized treatment plan is put together for you based on:
- The location and size of your glioblastoma
- Your age and general health
- Your ability to tolerate specific treatments
- Your preferences
Treatment for glioblastoma may include one or a combination of the following options:
- Craniotomy An open surgery on the brain is called a craniotomy. Surgery to remove a tumor such as a glioblastoma is usually the first step when possible. It definitively establishes the diagnosis as well as provides the initial treatment. This type of surgery is best performed by specialized neurosurgeons who are experienced in operating on tumors. Most of the time, the neurosurgeon will also use a high-powered operative microscope and a computer-guided imaging system to navigate precisely around the tumor during the craniotomy. A special fluorescent dye (5-aminolevulinic acid, 5-ALA) may be used to help define the tumor using the operative microscope. Unfortunately, individual tumor cells creep beyond the apparent border of the glioblastoma into normal brain so that additional treatments are needed. You generally will stay in the hospital for a few days after surgery, with the length of stay determined by the extent of surgery.
- Chemotherapy Following surgical resection or stereotactic biopsy for glioblastoma, an oral chemotherapy drug called temozolomide (Temodar®) is frequently prescribed. A molecular marker (promoter methylation of MGMT) may indicate a better response to this chemotherapy agent. Occasionally chemotherapy-soaked wafers may be placed against the wall of the cavity left behind after the tumor has been removed.
- Immunotherapy Bevacizumab (Avastin®) stimulates your immune system to block new blood vessel growth to the tumor. It typically is used in the treatment of glioblastoma which has returned following initial treatments.
- Radiation This treatment uses high-energy radiation beams to kill the brain cancer cells by damaging their DNA. There are a variety of radiation treatments available. Your doctors will choose the best form of radiation treatment to fit your particular needs.
- Steroids These medicines may improve or even provide temporary relief of brain tumor symptoms by reducing the edema (swelling) around the tumor. The most commonly used steroid in neurosurgery is dexamethasone (Decadron®).
- Anti-seizure medicines – These medicines are prescribed to prevent further seizures. Sometimes they may also be used for a short period around the time of surgery. A seizure is a surge of synchronized electrical activity in the brain that may produce alteration in awareness or consciousness, repetitive shaking or stiffness of one or more limbs, as well as loss of physical control and bowel or bladder function.
- Therapies – A brain tumor and its subsequent treatments may affect your motor skills, speech, swallowing or even cognitive abilities, depending on its size and location. Physical, occupational and speech therapies may be used to help regain or compensate for any diminished abilities. These rehabilitative therapies may be performed in an inpatient or outpatient setting.
Follow-up care includes regular monitoring of your clinical condition as well as routine surveillance of your imaging studies (usually MRI or CT scans). Often, you may be seen in a coordinated fashion by the specialists who have been treating you (neurosurgeon, radiation oncologist and medical oncologist).