Glioblastoma Diagnosis

If you have a brain tumor, it is important to get the most accurate diagnosis possible. This will help your doctor pinpoint the tumor to give you the most advanced treatment with the least impact on your body.

At MD Anderson, we have the most sophisticated equipment available to identify brain tumors and find out exactly how far they may have spread in the central nervous system.

Our specialized staff truly sets us apart. The Brain and Spine Center has renowned neuropathologists who focus solely on diagnosing brain and spine tumors.

These experts were instrumental in writing the World Health Organization book that defines every type of brain tumor and provides standard classifications for doctors worldwide. When called on to give a second opinion, they change diagnoses for up to 10% of patients first diagnosed at another hospital. Their expertise and experience can make a big difference in brain tumor treatment success.

Glioblastoma diagnostic tests

The process of diagnosing glioblastoma is essentially the same as testing for other brain tumors.

If you have symptoms that signal a brain tumor, your doctor will examine you and ask questions about your health, your lifestyle and your family’s medical history.

If the doctor decides further testing is needed, he or she will order an imaging exam. One or more of the following tests may be used to find out if you have a brain tumor. These tests also may be used to find out if treatment is working.

Imaging exams: Imaging exams let doctors see tumors in and around the brain. Glioblastoma imaging exams include:

• CT (computed tomography) scans
• MRI (magnetic resonance imaging)
• ABTI (advanced brain tumor imaging): This imaging technique provides doctors with highly detailed information on the tumor. It is used to evaluate new tumors, identify recurrence and guide treatment decisions.

Biopsy: While imaging tests may show an area where there could be a brain tumor, doctors need a tissue sample to definitively diagnose a primary brain tumor. Tissue samples are obtained by a biopsy. For glioblastoma, a tissue sample is usually retrieved during surgery to remove the tumor. A pathologist will then examine the cells to make a diagnosis. Since glioblastoma is a very complex disease, it is best to work with a pathologist with extensive experience in diagnosing brain cancers to get an accurate diagnosis from the very beginning.

Molecular testing: Some primary brain tumors, including glioblastoma, are defined by their key molecular features that are results of mutations in the tumor. These features can be used to diagnose a tumor, provide a more accurate prognosis and enhance the treatment plan. This is an area of ongoing study and more mutations will almost certainly emerge. Currently, the key molecular subtypes of glioblastoma include:

• IDH mutation: IDH is a gene that produces proteins that help repair damaged DNA. In general, patients whose tumor has an IDH mutation have a better prognosis than those who do not have the mutation (known as IDH wildtype). Doctors believe this is because the mutation limits the ability of IDH proteins to repair cancer cell DNA.
• MGMT promoter methylation: MGMT is an enzyme that can make cancer cells more resistant to therapy. When the DNA associated with producing this enzyme is mutated through a process called methylation, less MGMT is made. Glioblastoma with the MGMT promoter methylation mutation may respond better to treatment. Testing for the MGMT mutation is required for many brain tumor clinical trials.