Glioblastoma also known as glioblastoma multiforme (GBM) or grade IV astrocytoma is a type of brain cancer. It is by far the most common type of malignant brain tumour among adults. And it is usually very aggressive, which means it can grow fast and spread quickly.
Attention was drawn to this form of brain cancer when Senator Ted Kennedy was diagnosed with glioblastoma and ultimately died from it.
Glioblastoma represents about 15.4% of all primary brain tumours. They increase in frequency with age, and affect more men than women. Only 3% of childhood brain tumours are glioblastomas.
Glioblastomas are tumours that arise from astrocytes, the star-shaped cells that make up the “glue-like,” or supportive tissue of the brain. These tumours are usually highly cancerous because the cells reproduce quickly and they are supported by a large network of blood vessels. Dead cells may also be seen, especially toward the centre of the tumour. Because these tumours 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.
In adults, this cancer usually starts in the cerebrum, the largest part of your brain. They are generally found in the cerebral hemispheres of the brain, but can be found anywhere in the brain or spinal cord.
There are two types of glioblastomas:
Primary, or de novo: These tumours tend to form and make their presence known quickly. This is the most common form of glioblastoma; it is very aggressive.
Secondary: These tumours have a longer, somewhat slower growth history, but still are very aggressive. They may begin as lower-grade tumours which eventually become higher grade. They tend to be found in people 45 and younger, and represent about 10% of glioblastomas.
Because glioblastomas can grow rapidly, the most common symptoms are usually caused by increased pressure in the brain. These symptoms can include:
Depending on the location of the tumour, patients can develop a variety of other symptoms such as:
weakness on one side of the body,
changes in mood or personality,
memory and/or speech difficulties,
and visual changes.
What Causes Glioblastoma?
There is nothing to do or avoid doing that would have prevented one from developing a brain tumour.
As with most brain tumours, the cause of glioblastoma is not known.
A doctor who specializes in diagnosing and treating brain disorders (a neurologist) will give you a complete exam. You may get an MRI or CT scan and other tests, depending on your symptoms.
Glioblastoma can be difficult to treat because the tumours contain so many different types of cells. Some cells may respond well to certain therapies, while others may not be affected at all. This is why the treatment plan for glioblastoma may combine several approaches.
The first step in treating glioblastoma is a procedure to make a diagnosis, relieve pressure on the brain, and safely remove as much tumour as possible through surgery. Because glioblastomas have finger-like tentacles, they are very difficult to completely remove. This is particularly true when they are growing near the parts of the brain that control important functions such as language and coordination.
Radiation and chemotherapy may be used to slow the growth of tumours that cannot be removed with surgery. Chemotherapy may also be used to delay the need for radiation in young children.
However, not all glioblastomas have the same biologic abnormalities. This may be the reason different patients respond differently to the same treatment and why different patients with the same tumour have different outcomes. Researchers continue to study the common characteristics of long-term brain tumour survivors, and how personalized and targeted treatments may be optimally used to treat brain tumour patients.
Outlook and Survival Rates
Only modest advancements in the treatment of glioblastoma have occurred in the past 25 years. Although current therapies remain palliative, they have been shown to prolong quality survival.
Many things can affect how well someone does when they have cancer, including glioblastomas. Doctors often can’t predict what someone’s life expectancy will be if they have a glioblastoma. But they do have statistics that track how large groups of people who’ve had these conditions tend to do over time.
Mean survival is inversely correlated with age, which may reflect exclusion of older patients from clinical trials.
Without therapy, patients with glioblastoma multiformes uniformly die within 3 months. Patients treated with optimal therapy, including surgical resection, radiation therapy, and chemotherapy, have a median survival of approximately 12 months, with fewer than 25% of patients surviving up to 2 years and fewer than 10% of patients surviving up to 5 years. Only about 2.9% may survive up to 10 years. Younger people tend to fare the best.
Whether the prognosis of patients with secondary glioblastoma is better than or similar to the prognosis for those patients with primary glioblastoma remains controversial.