Glioblastoma

Symptoms

Glioblastoma symptoms can vary widely depending on where the tumor develops in the brain, how large it is, and how quickly it grows. If you notice new or worsening neurologic symptoms, contact your health care provider right away.

Common Symptoms

• Headaches that persist or worsen over time, often more noticeable in the morning.
• Seizures, which may appear as confusion, staring spells, muscle twitching, or convulsions.
• Nausea or vomiting, especially when accompanied by headaches.
• Changes in vision, such as blurred or double vision or loss of peripheral vision.
• Difficulty with speech or language, including trouble finding words.
• Memory issues, confusion, or changes in personality or mood.
• Weakness or numbness, or problems with balance and coordination.
• Fatigue or decreased energy levels.
  

Why Symptoms Differ

Glioblastoma most often develops in the frontal lobe—which can help control speech, behavior, memory, or movement—or the temporal lobe, which supports language, hearing, and memory formation. However, these tumors can arise anywhere in the brain, leading to a wide range of possible symptoms.

Diagnosis and Stages

To understand your condition and create the best treatment plan, your care team will begin by reviewing your medical history and performing a detailed neurologic exam. Based on these results, your team may order additional tests. Brain imaging such as MRI, and in some cases CT, helps visualize the brain and identify the size and location of the tumor. In many cases, a biopsy or surgical removal of tumor tissue is needed to make a definitive diagnosis, allowing specialists to examine the cells under a microscope.

Your doctors may also conduct molecular testing of the tumor, including markers such as IDH status and MGMT promoter methylation, to guide treatment decisions and determine eligibility for specific clinical trials. A lumbar puncture (spinal tap) is used less commonly and is reserved for situations where a tumor may have spread to the tissue surrounding the brain or into the spinal fluid.

Imaging plays a key role in diagnosing brain tumors. CT and MRI scans help your care team understand where a tumor is located and whether it is affecting other areas of the brain. While imaging can show suspicious areas, only a tissue sample can confirm the presence, type, and grade of a primary brain tumor. Tissue can be obtained through a needle biopsy or during surgery that removes part or all of the visible tumor. Your neurosurgeon will recommend the approach that is safest and most appropriate for your situation.

In certain cases, your team may perform a lumbar puncture to collect a small sample of cerebrospinal fluid. This sample is examined to see whether tumor cells have spread to the meninges—the protective layers surrounding the brain and spinal cord.

Molecular diagnosis is another important part of modern cancer care. Because cancers differ at the molecular level, identifying these unique features allows your doctors to tailor treatment more precisely to your tumor. Some patients may also benefit from genetic testing to understand whether inherited mutations could influence their cancer risk or treatment options.

Together, imaging and tissue testing provide the information needed to confirm whether a brain tumor is present and to accurately determine its type and grade, ensuring you receive the most appropriate care.

Glioblastoma Stages

Glioblastoma is not staged like many other cancers. Instead, brain tumors are classified by grades, which describe both the appearance of the cells under a microscope and the presence of various molecular markers and are used to determine how aggressively the tumor is likely to grow. According to the World Health Organization (WHO) grading system, all glioblastomas are grade 4 tumors, the highest and most aggressive grade. This is because glioblastoma cells look highly abnormal, possess certain molecular profiles, reproduce quickly, and tend to invade nearby brain tissue. They also form new blood vessels to support their rapid growth and may contain areas of necrosis (dead tissue). These features are present at diagnosis, which is why glioblastoma is always treated as an advanced, fast‑growing cancer.

Together, imaging, tissue sampling, and molecular testing provide the comprehensive information needed to determine whether a brain tumor is present and to accurately define its type and grade. This ensures that each patient receives a treatment plan designed specifically for their tumor’s biology.

Treatments

Treatment plans are individualized and may combine several approaches. At the University of Colorado Anschutz Cancer Center, patients are cared for by a multidisciplinary team of neurosurgeons, neuro‑oncologists, radiation oncologists, neuroradiologists, neuropathologists, rehabilitation specialists, and supportive‑care experts.

Surgery

Goal: Safely remove as much tumor as possible while relieving pressure on the brain. Because glioblastoma infiltrates normal brain tissue, surgery alone cannot eliminate every tumor cell.

To maximize safety and precision, our neurosurgeons may use:

• Awake craniotomy to monitor speech or other functions during the procedure.
• Intraoperative MRI for real‑time surgical guidance.
• Fluorescence‑guided surgery, in which a special agent causes tumor cells to glow and stand out from healthy tissue.
• For patients who cannot undergo open surgery, Laser Interstitial Thermal Therapy (LITT) may be an option. LITT is a minimally invasive technique that uses a laser probe to heat and destroy targeted tumor tissue.

Radiation Therapy

Radiation therapy uses high‑energy beams to kill cancer cells or slow tumor growth.

Most patients receive:

• IMRT (Intensity‑Modulated Radiation Therapy) or VMAT, which shape radiation precisely around the tumor while protecting surrounding healthy tissue.
• Stereotactic radiosurgery (such as Gamma Knife) for select patients with small, focal, or recurrent tumors.
• Common short‑term effects may include fatigue, hair loss at the treatment site, mild skin irritation, and temporary brain swelling (often managed with medication). Long‑term effects vary based on dose and treatment location and will be reviewed with your care team.

Chemotherapy

The standard chemotherapy for newly diagnosed glioblastoma is temozolomide, an oral medication given during radiation and then in additional monthly cycles.

For recurrent disease, other oral or IV chemotherapy options may be used, often within a clinical trial. Blood counts and side effects—such as fatigue, nausea, or infection risk—are monitored closely.

Targeted Therapy

A small subset of tumors carry molecular changes that make them eligible for targeted treatments. These therapies focus on specific pathways that drive tumor growth. Side effects vary depending on the drug but are often manageable with supportive care.

Tumor Treating Fields (TTF)

TTF therapy uses low‑intensity, alternating electric fields delivered through adhesive scalp patches to disrupt cancer cell division. It is typically used after chemoradiation and worn for most hours of the day. It requires the head to be shaved. The most common side effect is scalp irritation and/or thinning.

Clinical Trials

Several clinical trials aimed at improving outcomes for patients with glioblastoma are available at the CU Anschutz Cancer Center. If you are interested in participating in a clinical trial, please speak with your doctor to discuss whether any current studies may be appropriate for your treatment.

Supportive & Rehabilitative Care

Comprehensive supportive care is a core part of neuro‑oncology at CU Anschutz Cancer Center. Your team may recommend:

• Anti‑seizure medications.
• Steroids (when appropriate) to reduce swelling.
• Physical, occupational, and speech therapy.
• Cognitive rehabilitation.
• Nutrition counseling.
• Social work services.
• Palliative care to support comfort, function, and quality of life at any stage.

Recurrent Glioblastoma

Because microscopic tumor cells remain after initial treatment, most glioblastomas eventually recur. Options may include:

• Repeat surgery (when safe and appropriate).
• Re‑irradiation for select patients.
• Additional chemotherapy, targeted therapy, TTF, or LITT.
• Enrollment in clinical trials offering novel drugs, immunotherapies, device‑based treatments, or combination strategies.

Your care team will partner with you to align treatment decisions with your goals and priorities.