Tests to Diagnose Glioblastoma Brain Tumors Everyday Health MenuNewslettersSearch Brain Tumor Tests to Diagnose Glioblastoma Brain Tumors Glioblastomas are the most common type of brain tumor in adults. Tests to gauge whether a patient has this kind of tumor range from a medical history and neurological assessment to brain scans. By Laura NewmanMedically Reviewed by Conor Steuer, MDReviewed: September 19, 2022Medically ReviewedCT scan sequence of a patient with a glioblastoma.Getty ImagesGlioblastomas are a type of tumor that originate in the brain, and are therefore referred to as primary brain tumors. Glioblastomas are rare before age 15, and the incidence escalates after age 45, peaking in the fifties and sixties. The median age for initial diagnosis is age 65. (1) Statistics suggest that the overall incidence of glioblastomas is rising, but some statisticians think that this may not be a true rise, but rather a result of imaging tests being more common and widespread now, so that tumors are being spotted more readily than before. But environmental factors could also be contributing to this apparent rise in numbers. Where Should You Go to Get Your Symptoms Assessed If you or your doctor thinks you might have a glioblastoma, you will be referred to a neurologist for tests. Ask your primary care doctor to refer you to a doctor and institution that treats a high volume of patients with brain tumors. This is because a large national study of patients with glioblastoma found that as many as 40 percent of patients diagnosed at high-volume centers live about three-and-one-half months longer than patients treated at lower-volume centers. The study also found that many patients treated at low- and medium-volume centers were less likely to even receive any treatment. High-volume centers are usually academic medical centers or large hospitals located in cities or in suburban areas nearby. (2) Your First Appointment What to Expect and How to Prepare Prepare for Your Appointment by Writing Down Notes About Your SymptomsInclude in your notes how long you’ve had specific symptoms, when these appear, whether anything triggers them, and if they have gotten worse.Discuss with family or friends to see if they have noticed anything out of the norm for you. Often family or friends notice things are off well before we do.Ask yourself whether you have any specific concerns about what is going on so that the doctor addresses them. Also, keep a small notebook handy at home so that you can log your symptoms going forward.Bring your notes to the appointment and see if your spouse or close friend can accompany you when you see the doctor. Bringing along your spouse, sibling, or significant other can provide a lot of support. At your appointment, the neurologist will ask you about your symptoms, take a medical history (ask questions about your current and past health), and conduct a neurological exam. During a neurological exam, your doctor will check your balance, reflexes, coordination, vision, hearing, sensation, and short-term memory. Your doctor will also look to see if you have any external swelling around your eyes, caused by pressure on the optic nerve. A neurological examination is inadequate for making the diagnosis. Still, the exam might eliminate a brain tumor as the problem, or point to more testing for a definitive diagnosis. If, at the conclusion of the visit, the neurologist suspects that you have a brain tumor, you will be referred for medical imaging (radiology) so that the doctors can get detailed pictures of your brain. Imaging Tests to Detect the Presence of a Tumor Scans of your brain provide extremely useful information as to whether a tumor exists, where a tumor sits, whether it is pressing upon any areas, and how it might affect body functions controlled by specific parts of the brain. A trained radiologist will read your scan and report what the scan shows to your neurologist. Magnetic resonance imaging (MRI) and computerized tomography (CT) scans are the two main types of imaging tests required to make a diagnosis. Usually, these scans are done with a contrast dye, which makes it easier to see details. Contrast for brain imaging is injected into one of your veins before or during your MRI or CT scan. MRI Scans: The Most Commonly Used Imaging Study for Brain Tumors MRI scans use magnetic fields, radio waves, and computer technology to generate images of the soft tissues of the brain. They are considered the optimum form of imaging because they use no radiation. During an MRI scan of the brain, patients lie down on a table that slides into a tunnel-like opening in the MRI machine. Once inside, you will be asked to lie absolutely still. Magnetic fields surround the head and a radio frequency pulse makes loud noises during the test. Specialized forms of MRI are available, but not essential for diagnosis. These include MR angiography, MR spectroscopy, MR perfusion, and functional MR. CT Scans CT scans may also be used in the diagnostic process. CT scans are capable of creating images of your brain and spinal cord, and can reveal soft tissue, bone structure near the tumor, collections of calcium within tumors, bleeding, and swelling. These scans involve low doses of radiation and merge together multiple X-ray images taken from different angles to generate a three-dimensional view of the brain. During a CT scan, the patient lies down on a table that slides through a doughnut-shaped opening. The CT scanner goes around the head several times, permitting the X-rays to penetrate the brain from multiple directions. This permits thousands of thin cross-sections of the brain to get fed into the computer to generate a picture. CT tends to be used less frequently for brain tumor assessments. It is particularly useful for people with certain metal instruments in their body, such as pacemakers. For these people, MRI is not an option due to the magnetic fields, and CT scans are used instead. Molecular Tests Increasingly Common in Directing Treatment Molecular tests are not essential for diagnosis, but they can be useful for treatment selection, predicting treatment response to chemotherapy, and prognosis. This is a rapidly moving field, meaning as new targeted drugs emerge for treating tumors become available, they could be incorporated shortly after diagnosis. Genetic abnormalities are more common in glioblastoma cells than they are in other brain cancers. Exactly what causes these abnormalities remains unknown. Possible environmental factors include high-dose ionizing radiation, cumulative exposure to chemicals and other carcinogens, other environmental triggers yet to be identified, and genetic mutations. (3) Next Steps Taking a Biopsy of the Tumor A biopsy is necessary for a definitive glioblastoma diagnosis. A biopsy involves taking some tissue from your brain to see if you have a cancerous growth. It also will tell what types of cells are present. A neurosurgeon removes a piece of tumor surgically. A pathologist examines it under a microscope and makes a diagnosis. In cases where the tumor is located in a key part of the brain or a patient is too sick for surgery, a needle biopsy, known as a stereotactic needle biopsy, is done. A tumor sample is obtained by inserting a needle through the skull into the brain. Glioblastomas There Are Three Types Glioblastomas used to be categorized under one umbrella category, but in 2016 the World Health Organization (WHO) led an effort to recategorize them into three broad categories. Working with leading neuro-oncologists and neuropathologists, the WHO identified three broad categories based on genetic information (molecular markers), in addition to the longstanding method of examining tumor tissue taken from biopsy. Of the three categories, IDH-wild type glioblastoma accounts for 90 percent of cases and is the most common type in patients over age 55. (4) The hope is that these new categories will prove valuable in guiding treatment as new therapies capable of targeting specific molecular markers become available. Coping With a Brain Tumor Diagnosis A diagnosis of a brain tumor is scary — they are highly malignant and lethal. Fortunately, there are resources you can turn to for support. Brain Tumor Patient Caregiver and Mentor Support Many brain cancer and cancer organizations have information on where to find support groups. Some are in-person, others are via computer:The American Brain Tumor Association has a database, organized by ZIP code, of support groups for patients and caregivers, as well as mentors. Mentors are often patients or family members of patients who have already gone through this and can provide support. The ABTA also has links to online support groups and a Facebook page.Your doctor, hospital, or community may have support groups. Ask about them at your next visit. Should You Get a Second Opinion A diagnosis of a glioblastoma is serious. Meeting with your doctor may feel overwhelming, and many people seek second opinions to be sure that they are comfortable with their doctor. The American Cancer Society has a fact sheet on this that could prove helpful. NEWSLETTERS Sign up for our Cancer Care Newsletter SubscribeBy subscribing you agree to the Terms of Use and Privacy Policy. Editorial Sources and Fact-Checking Glioblastoma (GBM). American Brain Tumor Association. April 2022.Koshy M, Sher DJ, Spiotto M, et al. Association Between Hospital Volume and Receipt of Treatment and Survival in Patients With Glioblastoma. Journal of Neuro-Oncology. December 2017.Glioblastoma Causes. Moffitt Cancer Center.Louis DN, Perry A, Reifenberger G, et al. The 2016 World Health Organization Classification of Tumors of the Central Nervous System: A Summary. Acta Neuropathologica. June 2016.Additional SourcesMichaud D, Schiff D, Batchelor T. Incidence of Primary Brain Tumors. UpToDate. February 23, 2021.Brain Tumor Support Groups. American Brain Tumor Association.Getting a Second Opinion. American Cancer Society. July 25, 2019.Show Less The Latest in Brain Tumor How Doctors Grade Glioblastoma Brain TumorsBrain tumors are staged differently from tumors in the rest of the body. 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