Glioblastoma Multiforme (GBM)

The diagnosis annually of GBM is 2 to 3 per 100,000 people in the United States and Europe.

What is Glioblastoma Multiforme?
Glioblastoma, also known as glioblastoma multiforme, GBM or grade IV astrocytoma, is a fast-growing, aggressive type of central nervous system tumor that forms on the supportive tissue of the brain. Glioblastoma is the most common grade IV brain cancer. Glioblastomas arise from astrocytes—the star-shaped cells that make up the “glue-like,” or supportive tissue of the brain. These tumors are usually highly malignant (cancerous) because the cells reproduce quickly and they are supported by a large network of blood vessels.

Glioblastomas are generally found in the cerebral hemispheres of the brain, but can be found anywhere in the brain or spinal cord. Glioblastomas usually contain a mix of cell types. It is not unusual for these tumors to contain cystic mineral, calcium deposits, blood vessels, or a mixed grade of cells.

Glioblastomas are usually highly malignant—a large number of tumor cells are reproducing at any given time, and they are nourished by an ample blood supply. Dead cells may also be seen, especially toward the center of the tumor. Because these tumors come from normal brain cells, it is easy for them to invade and live within normal brain tissue. However, glioblastoma rarely spreads elsewhere in the body.

 There are two types of glioblastomas:

  • Primary, or de novo: These tumors tend to form and make their presence known quickly. This is the most common form of glioblastoma; it is very aggressive.
  • Secondary: These tumors have a longer, somewhat slower growth history, but still are very aggressive. They may begin as lower-grade tumors which eventually become higher grade. They tend to be found in people 45 and younger, and represent about 10% of glioblastomas.

GBMs are biologically aggressive tumors that present unique treatment challenges due to the following characteristics:

  • Localization of tumors in the brain;
  • Inherent resistance to conventional therapy;
  • Limited capacity of the brain to repair itself;
  • Migration of malignant cells into adjacent brain tissue;
  • The variably disrupted tumor blood supply which inhibits effective drug delivery; 
  • Tumor capillary leakage, resulting in an accumulation of fluid around the tumor; (peritumoral edema) and intracranial hypertension;
  • A limited response to therapy;
  • The resultant neurotoxicity of treatments directed at gliomas.

Glioblastoma cancer symptoms
Symptoms of glioblastoma vary depending on the location of the tumor, but they may include:

  • Persistent headaches
  • Double or blurred vision
  • Nausea
  • Vomiting
  • Loss of appetite
  • Changes in mood or personality
  • Changes in ability to think and learn
  • Memory loss
  • New onset of seizures
  • Muscle weakness
  • Speech difficulty

NOTE: These symptoms may be attributed to a number of conditions other than cancer. It is important to consult with a medical professional for an accurate diagnosis.

Sophisticated imaging techniques can very accurately pinpoint the location of brain tumors. Diagnostic tools include computed tomography (CT or CAT scan) and magnetic resonance imaging (MRI). 

Intraoperative MRI may also be useful during surgery to guide tissue biopsies and tumor removal. Magnetic resonance spectroscopy (MRS) is used to examine the tumor's chemical profile, with postron emission tomography (PET scan) helpful in detecting tumor recurrence.

Common glioblastoma treatments include:

Surgery: Surgical resection, which requires a craniotomy, is typically the first stage of treatment for patients with glioblastomas. Surgery may also allow for the removal of tumor tissue to relieve pressure in the brain caused by the tumor.

Radiation: It may also be necessary to treat glioblastomas when surgery is deemed unsafe or is not recommended for another reason. Radiation therapy may be used alone, with chemotherapy or with targeted therapies. 

  • Intensity modulated radiation therapy (IMRT): IMRT is a state-of-the-art radiation delivery system that is used to treat hard to reach tumors. It can also spare healthy tissue from radiation therapy. In IMRT, the radiation beams are broken up into smaller beams and the intensity of each of these smaller beams can be changed. This means that the more intense beams, or the beams giving more radiation, can be directed only at the tumor. It is most useful to treat a tumor that is near critical parts of the brain, such as the brain stem and areas that control sight.
  • Stereotactic radiation therapy: this treatment focuses radiation from various angles to the outline of the tumor. This technique is designed to reduce damage to healthy tissue. Because the procedure does not require an incision, it typically leads to less discomfort, shorter recovery times and fewer complications than surgery.

Chemotherapy: Several chemotherapy drugs taken orally or intravenously are available to manage the symptoms of glioblastoma. Chemotherapy and radiation therapy are typically the recommended course of treatment for nearly all glioblastomas. Following surgery, carmustine wafers may also be implanted. After a surgeon operates to remove the cancerous tissue in the brain, up to eight dime-sized wafers are implanted in the space where the tumor was. Over the next few weeks, the wafers slowly dissolve while filling surrounding cells with medication. The goal is to kill tumor cells left behind after surgery. Chemotherapy along with Optune has been approved for adjuvant therapy once radiation is complete.

Targeted therapy: are medicines that target the parts of cancer cells that make them unlike normal cells. These new drugs are used more often to treat brain tumors than standard chemotherapy. Targeted therapy can help when other treatments are not working as well. They can also have less-severe side effects than standard chemotherapy medicine.   

Want to learn more?

The following are organizations and/or websites dedicated to providing information and education surrounding Glioblastoma Multiforme. These organizations are dedicated to research, education, awareness, and/or support. They are listed in Alphabetical order without any preference or prejudice. Listing these organizations is not a recommendation or referral in any regard for seeking treatment or consultation or support for treatment.

America Brain Tumor Association
Cancer Treatment Centers of America
National Association of Neurological Surgeons
National Brain Tumor Society
National Center for Biotechnology Information

​Information on this page taken directly from:
America Brain Tumor Association
Cancer Treatment Centers of America
National Association of Neurological Surgeons
National Brain Tumor Society