Brain cancer is usually diagnosed after an individual notices symptoms (such as headaches, visual problems, or seizures) and has been referred to a neurologist, a doctor who specializes in diseases of the central nervous system.
A diagnosis of brain cancer begins with a thorough physical exam, during which a neurologist will ask about symptoms such as seizures, persistent headaches, or other indications of pressure inside the skull, like nausea/vomiting. The neurologist will also ask about an individual’s personal medical history, including past illnesses and treatments, as well as family history. The neurologist will check the patient’s reflexes, balance, coordination, and muscle strength, along with hearing and vision, for abnormalities. Swelling or protrusion of the blind spot at the back of the eye can provide clues to the type of brain tumor. The neurologist will also be assessing the individual for their mental status and checking for cognitive dysfunction.
If the physician suspects a brain tumor, imaging tests and other diagnostic tests will be ordered to confirm and provide details about the tumor type, size, location, and speed of growth.
An MRI scan of the brain is the diagnostic tool of choice. An MRI showing multiple lesions is very suggestive of metastatic tumors. A diagnostic work-up may be performed to look for the primary cancer site. This work-up often includes a chest X-ray, CT scan of the chest, abdomen, and pelvis, or a mammogram. A PET scan may be performed.
More About Some Imaging Tests:
X-rays can produce images of bones and organs and provide a quick and noninvasive glimpse into the body.
A CT scan relies on sophisticated X-ray devices connected to computers. It may be used to get a quick view to see whether or not there is a brain tumor; it can also reveal whether there are calcifications in the tumor.
An MRI uses a strong magnetic field and radio waves to create detailed images that reveal the location of a tumor and which parts of the brain are involved prior to surgery. Sometimes an MRI with contrast enhancement is performed; “contrast” means a special dye is injected into an individual’s blood vessels to reveal tumors.
The neurologist may refer the patient to a neurosurgeon for further evaluation. A surgical tissue biopsy may be required for a definitive diagnosis. This is because current research suggests the importance of identifying specific gene changes or biomarkers (molecules) to confirm certain kinds of cancers. In addition, it may predict how an individual will respond to different treatments, which will assist in planning appropriate and effective next steps as well as whether a person is suitable for a particular clinical trial.
Depending on the location and type of tumor, a biopsy is not always possible. Often, if a tumor is large or causing pressure on part of the brain, the neurosurgeon will advise removing the entire tumor and performing a biopsy as part of that larger procedure.
Reviewed by: Rohan Ramakrishna, MD
Last reviewed/last updated: August 2024
