Introduction: Who Should Undergo Diagnostics

Anyone experiencing symptoms that might suggest a problem in the brain or spinal cord should seek medical attention. For malignant astrocytoma, these symptoms vary widely depending on where the tumor is located. People who develop seizures (sudden episodes of uncontrolled electrical activity in the brain causing changes in behavior or consciousness), persistent headaches, nausea and vomiting, changes in personality, problems with speech, or feelings of extreme tiredness or weakness should consult a healthcare provider.^[1][2] These signs can appear gradually or suddenly, and they may worsen over time as the tumor grows.

In the spinal cord, malignant astrocytomas can cause pain in the affected area, numbness, or weakness that may spread to other parts of the body. Because these symptoms can also be caused by many other conditions, it is important not to assume the worst, but equally important not to ignore warning signs. Early diagnosis allows for timely treatment, which can make a significant difference in quality of life and outcomes.^[1]

People with certain risk factors may also benefit from closer monitoring. The only well-established risk factor for astrocytomas is exposure to ionizing radiation (a type of high-energy radiation used in some medical treatments).^[7] For example, children who received radiation therapy to the head for conditions like acute lymphocytic leukemia have a much higher risk of developing a brain tumor later in life. Additionally, a small number of patients have a family history of genetic conditions such as Li-Fraumeni syndrome, neurofibromatosis type 1, tuberous sclerosis, or Turcot syndrome, which can increase the risk of astrocytoma.^[10] If you belong to any of these groups, discussing diagnostic options with your doctor is advisable.

Classic Diagnostic Methods

The diagnostic process for malignant astrocytoma typically begins with a neurological examination. During this exam, a healthcare provider asks detailed questions about your symptoms and medical history. They will check your vision, hearing, balance, coordination, strength, and reflexes. Any problems found in these areas can help the doctor understand which part of the brain or spinal cord may be affected by the tumor.^[12] This examination is a crucial first step because it guides the choice of further tests.

After the neurological exam, imaging tests are the next step. Magnetic resonance imaging (MRI) is the most commonly used imaging test for diagnosing brain tumors. An MRI uses powerful magnets and radio waves to create detailed pictures of the inside of your brain or spinal cord. It can show the exact location and size of the tumor, and it helps doctors see how the tumor relates to surrounding tissues.^[12] Sometimes, specialized types of MRI are used, such as functional MRI (which shows brain activity in real time), perfusion MRI (which measures blood flow in the brain), and magnetic resonance spectroscopy (which analyzes the chemical composition of tissues). These advanced techniques provide even more information about the tumor’s characteristics.

In some cases, doctors may also use a computed tomography (CT) scan, which uses X-rays to create cross-sectional images of the brain. CT scans are faster than MRIs and can be helpful in emergency situations or when MRI is not available. Another imaging test that may be used is a positron emission tomography (PET) scan, which shows how tissues and organs are functioning by detecting the movement of a radioactive tracer injected into the body. PET scans can help distinguish between active tumor tissue and scar tissue from previous treatments.^[12]

The most definitive diagnostic test is a biopsy, which involves removing a small sample of tissue from the tumor for laboratory examination. In many cases, the biopsy is performed during surgery to remove the astrocytoma. A neurosurgeon (a surgeon who specializes in brain and spinal cord surgery) carefully extracts tissue from the tumor. If the tumor is located in a hard-to-reach area, a needle biopsy may be used instead. During this procedure, a thin needle is guided to the tumor using imaging scans, and a small amount of tissue is extracted.^[12]

Once the tissue sample reaches the laboratory, a specialist called a neuropathologist examines it under a microscope. The pathologist looks at the appearance of the cells, checking how abnormal they look compared to healthy brain cells, how quickly they are growing, and whether new blood vessels are forming within the tumor. These features help determine the tumor’s grade, which ranges from 1 to 4. Grade 1 astrocytomas are the least aggressive, while grade 4 astrocytomas (also called glioblastomas) are the most aggressive.^[3][13]

Modern diagnostic approaches also include genetic and molecular testing of the tumor tissue. Scientists now know that certain changes in the tumor’s DNA (the genetic material inside cells) can affect how the tumor behaves and responds to treatment. One of the most important tests looks for mutations in a gene called IDH (isocitrate dehydrogenase). If the tumor has an IDH mutation, it is classified as “IDH-mutant astrocytoma.” If it does not have this mutation, it is classified as “IDH-wildtype,” which often means the tumor is more aggressive. These genetic findings are now a standard part of the diagnostic process and help doctors create a more personalized treatment plan.^[6][15]

Diagnostics for Clinical Trial Qualification

When patients are being considered for enrollment in clinical trials, additional diagnostic tests and criteria are often required. Clinical trials are research studies that test new treatments or combinations of treatments to find better ways to manage astrocytomas. Because these studies follow strict protocols to ensure safety and accuracy, participants must meet specific eligibility criteria based on their diagnosis and overall health.

One of the first requirements for clinical trial qualification is confirmation of the tumor type and grade through biopsy and pathology analysis. Trials often specify which grades of astrocytoma are eligible. For example, some trials may only accept patients with grade 3 or grade 4 tumors, while others may focus on grade 2 astrocytomas.^[14] The presence or absence of the IDH mutation is also a key factor, as some clinical trials are designed specifically for IDH-mutant or IDH-wildtype tumors.

In addition to tumor-specific diagnostics, patients must undergo general health assessments to ensure they are strong enough to participate in the trial. These assessments typically include blood tests to check kidney and liver function, as well as tests to evaluate the heart, lungs, and overall physical condition. Doctors use these results to determine whether a patient can safely tolerate the experimental treatment being tested.^[14]

Imaging studies, particularly MRI scans, are also used as baseline measurements before starting a clinical trial. These scans establish the size and location of the tumor at the beginning of the study, so that doctors can later compare new scans to see if the treatment is working. Throughout the trial, patients typically undergo regular MRI scans to monitor the tumor’s response.

Some clinical trials require additional specialized tests. For example, trials testing targeted therapies may require detailed genetic testing of the tumor to identify specific mutations or proteins that the treatment is designed to target. This ensures that the experimental therapy has the best chance of working for that particular patient. In some cases, trials may also require a test called a neurological examination at multiple time points to assess changes in brain function and symptoms over time.

Eligibility for clinical trials is not only based on diagnostic results but also on the patient’s treatment history. Some trials are designed for patients who have just been diagnosed and have not yet received treatment, while others are for patients whose tumors have returned after initial treatment. Doctors carefully review all of this information to match patients with the most appropriate clinical trials.