Diagnosis and Screening for Brain Cancer
After visiting their primary doctor or the emergency room with symptoms that indicate the possibility of brain cancer, most people will receive a brain or spine imaging test. Results of these imaging tests, along with a physical exam and review of your medical history and risk factors, will help with the diagnosis.
A CT scan, or computed tomography, is often the first imaging test you will receive. It is fairly quick and can show many abnormalities of the brain. Because certain tumors are hard to see with a CT scan, some people also will receive an MRI, or magnetic resonance imaging, of the brain or spine.
How is brain cancer diagnosed?
Interpreting a CT or MRI scan is often challenging because disease processes can look similar. For example, an aggressive primary brain tumor like glioblastoma can resemble a metastatic tumor that originated somewhere else in the body. These lesions can also look like a brain abscess (infection) or even multiple sclerosis. It is important to quickly and correctly diagnose these conditions because each requires a different evaluation and treatment. Effective treatment should begin promptly.
Radiologists are trained in reading and interpreting many different kinds of imaging studies, including X-rays, CT scans, MRIs and other imaging tests, from all parts of the body. Neuroradiologists have completed additional specialized training specifically focused on interpreting imaging studies of the brain and spinal cord.
Board-certified neuroradiologists at The University of Kansas Health System are available around the clock to review CT and MRI scans and discuss results with your care team.
Additional tests a neuroradiologist may recommend include:
- Magnetic resonance perfusion captures images of blood flow and volume, which is often elevated in aggressive tumors.
- Magnetic resonance spectroscopy looks at the chemical composition of the brain. The region of the brain that is of interest often appears to be abnormal in both aggressive and nonaggressive tumors.
- Positron emission tomography, or PET imaging, looks at metabolic activity in the body. Aggressive tumors typically grow quickly and consume a lot of nutrients. This activity can be seen with a PET scan.
A CT scan of the chest, and possibly the abdomen and pelvis, may be performed if you have risk factors for metastatic cancer or if your physician suspects it. This test gives specialists the opportunity to look at the lungs, adrenal glands, bone and other sites in the body that are often affected by metastatic cancers.
If your care team suspects an infection or autoimmune issue, they may conduct blood or spinal fluid tests. If a tumor is still possible based on test and evaluation results, additional specialists will join your care team to help guide further testing. These specialists may include neurosurgeons, neuro-oncologists and/or neurologists.
Role of neurosurgery in diagnosis
If CT or MRI scans indicate concern for a tumor, a neurosurgeon who is experienced in brain tumor surgery will join your care team. This is important for the accurate diagnosis and removal of as much underlying tumor as possible while leaving healthy tissue intact. Available evidence and general consensus among neurosurgeons and neuro-oncologists indicate that the more completely a tumor is surgically removed, the greater the chance of survival and controlling your symptoms. This is true for both malignant and nonmalignant tumors.
Role of neuropathology in diagnosis
A pathologist is a physician who is trained in analyzing tissue samples from all parts of the body, often using a microscope to identify fine details. These specialists understand the complicated interpretation of studies such as:
- Flow cytometry, which looks for important surface markers on hundreds of tumor cells
- Fluorescence in-situ hybridization testing for chromosome abnormalities in the tumor cells
- Polymerase chain reaction testing, which can amplify portions of the tumor cells' DNA
- Cytology, which looks at cells in fluid collections, usually spinal fluid
- Special stains and many others
The University of Kansas Cancer Center has one of the few neuropathologists in the Kansas City region.
Becoming board-certified in neuropathology requires focused training in studying diseases and conditions found in the brain and spine and interpreting tissue samples from these locations. Because many different brain conditions can appear to be quite similar under the microscope, a neuropathologist plays an important role in helping the care team arrive at the correct diagnosis.
Frozen section biopsy
Biopsies are performed when a small sample of tissue is taken from the tumor and examined under a microscope to make a diagnosis. As an additional safety check, the surgeon will remove a small tissue sample before surgery begins. The neuropathologist will quickly freeze, slice and examine it in real time. This frozen section procedure is performed minutes before the neurosurgeon begins to remove the suspected tumor. When the pathologist indicates that the mass indeed looks like a tumor and removal is appropriate, the neurosurgery team can proceed with confidence.
Once surgery is complete, the suspected tumor tissue is placed in special preservative and undergoes fixation overnight. This will cause the tissue to become firm, allowing it to be thinly sliced. If you have given consent to donate tumor tissue for use in clinical trials, a portion of the tissue is fixed for diagnosis while the rest is preserved and sent to the tissue bank. Slices of the fixed tumor tissue are placed onto glass slides and stained with different markers that aid the final diagnosis. Additional studies are often necessary for the full description of these tumors. These include FISH testing for chromosomes, PCR testing for MGMT, IDH mutation status and EGFR.
The University of Kansas Cancer Center maintains a biospecimen repository allowing banking of tumor tissue from many different types of tumors for support of ongoing research efforts. Any extra tissue not needed for diagnosis or clinical trial purposes can be preserved for use in future studies. Your name and other identifying information would not be included with this banked tissue.
Screening for brain cancer
Screening imaging tests can be part of the ongoing care for known cancer syndromes. Some people who have completed treatment and have no evidence of tumor regrowth will have repeated MRI scans over a long period of time. This is not classified as screening and is instead referred to as periodic restaging. Due to the rarity of brain and spine tumors, even in people with symptoms, it is unlikely to discover a tumor causing those symptoms.