all about glioblastoma

Glioblastoma 101

Glioblastoma, also known as GBM, is an aggressive type of cancer that occurs in the brain or spinal cord. It is the most common primary brain tumor in adults, characterized by rapid growth and a tendency to invade surrounding brain tissue.

What is Glioblastoma?

Glioblastoma is classified as a grade 4 astrocytoma by the World Health Organization (WHO).

This grading indicates a highly malignant tumor that arises from astrocytes, the star-shaped cells that form part of the supportive tissue of the brain. GBM is known for its heterogeneity, meaning it contains a variety of different cell types within the same tumor, which contributes to its complexity and resistance to treatment.

Tumor Location

The location of a glioblastoma brain tumor can affect what symptoms manifest as well as which treatment options will be the most effective. The presence of a brain tumor can cause damage to healthy brain tissue, disrupting the normal functions of that area.

  • Frontal Lobe

    Symptoms may include changes in personality, loss of inhibitions, difficulty planning or organizing, and weakness on one side of the body.

  • Parietal Lobe

    May cause difficulty with speech, problems with writing or math, and spatial disorientation.

  • Temporal Lobe

    Can affect memory, speech, and understanding language.

  • Occipital Lobe

    Often causes visual disturbances or loss of vision.

  • Cerebellum

    May lead to problems with balance, coordination, and fine motor skills.

  • Brain Stem/Spinal Cord

    Can cause issues with breathing, heart rate, and blood pressure, and may lead to paralysis.

Understanding Cancer Grades

Cancer grades describe the appearance of cancer cells under a microscope and indicate how quickly the tumor is likely to grow and spread. The grades range from I to IV:

Grade I and II

These lower-grade tumors grow more slowly and are less likely to invade nearby tissues.

Grade III and IV

These higher-grade tumors grow more rapidly and are more likely to infiltrate surrounding brain tissue.

Grade IV, the highest grade, signifies a highly aggressive form of cancer. In glioblastoma, this means the tumor cells are highly abnormal, proliferate quickly, and spread extensively into surrounding brain areas.

Malignant Tumor vs. Benign Tumor

Malignant Tumor

A malignant tumor refers to cancerous cells that have the potential to grow uncontrollably and invade nearby tissues. These cells can spread, or metastasize, to other parts of the body through the bloodstream or lymphatic system. Malignant tumors are more aggressive and can cause significant health issues by disrupting normal bodily functions and damaging healthy tissue.

Benign Tumor

In contrast, a benign tumor consists of non-cancerous cells that grow slowly and do not invade nearby tissues or spread to other parts of the body. While benign tumors can still cause health problems depending on their size and location, they are generally less threatening than malignant tumors.

Symptoms of Glioblastoma

Symptoms of glioblastoma can vary depending on the tumor's size, location, and rate of growth. Common symptoms include:

Headaches

Often severe and persistent, typically worse in the morning or after periods of sleep.

Seizures

A common presenting symptom in patients with GBM.

Cognitive and Personality Changes

Difficulty with memory, speech, and other cognitive functions, as well as changes in personality or behavior.

Nausea and Vomiting

Often due to increased intracranial pressure.

Weakness and Numbness

Usually on one side of the body.

Visual Changes

Such as blurred vision or loss of peripheral vision.

Causes and Risk Factors

The exact cause of glioblastoma is not well understood, but several risk factors have been identified:

  • Genetic Factors

    Certain genetic mutations and syndromes (e.g., Li-Fraumeni syndrome, Turcot syndrome) increase the risk of developing glioblastoma.

  • Age

    GBM is more common in older adults, particularly those over the age of 50.

  • Gender

    Males are slightly more likely to develop glioblastoma than females.

  • Exposure to Radiation

    Previous radiation therapy to the brain can increase the risk of glioblastoma.

Diagnosis

Diagnosing glioblastoma involves several steps:

1) Neurological Examination

To assess brain function and identify any deficits.

2) Imaging Tests

Magnetic resonance imaging (MRI) is the standard imaging technique used to detect glioblastoma. It provides detailed images of the brain and helps in determining the tumor's size and location.

3) Biopsy

A definitive diagnosis is made through a biopsy, where a sample of the tumor tissue is examined under a microscope to identify cancerous cells and determine the tumor's grade.

Treatment Options

Treatment for glioblastoma typically involves a multimodal approach:

  • Surgery

    The primary treatment is surgical resection to remove as much of the tumor as possible.

  • Radiation Therapy

    Following surgery, patients usually undergo radiation therapy to target any remaining cancer cells.

  • Chemotherapy

    Temozolomide (TMZ) is the most commonly used chemotherapy drug for glioblastoma, often given concurrently with radiation therapy.

  • Targeted Therapy

    Bevacizumab (Avastin), or biosimilars, inhibits the growth of blood vessels that supply the tumor.

  • Experimental Treatments

    Clinical trials may offer access to new and emerging treatments, such as immunotherapy and gene therapy.

    To learn more about clinical trials available for glioblastoma, visit ClinicalTrials.gov.

  • Tumor Treating Fields

    Tumor Treating Fields (TTF) therapy uses electrical fields delivered through scalp-attached pads, often combined with chemotherapy after radiation, to disrupt glioblastoma cell growth.

What is a Craniotomy?

A craniotomy is a surgical procedure where a section of the skull is temporarily removed to access the brain. This procedure is often performed to remove brain tumors, such as glioblastoma. Here’s how it typically works:

01 | Preparation

The patient is given anesthesia to ensure they are comfortable and pain-free during the procedure.

02 | Positioning

The head is placed in a fixed position to keep it still.

03 | Surgical Process

A section of the scalp is shaved and sterilized. An incision is made in the scalp, and a bone flap is removed to expose the brain.

04 | Tumor Removal

The neurosurgeon carefully removes as much of the tumor as possible while avoiding critical areas that control essential functions.

05 | Closure

Once the tumor is removed, the bone flap is replaced and secured, and the scalp is sutured back together.

During an awake craniotomy, the patient may be awake and responsive, allowing the surgical team to monitor brain function and minimize damage to vital areas responsible for movement, speech, and other critical functions. This approach helps ensure the safety and efficacy of the surgery.

Prognosis

The prognosis for glioblastoma is generally challenging, with a median survival time of 12-15 months following diagnosis. However, some patients live longer, particularly those who respond well to treatment. Factors that can influence prognosis include the patient’s age, overall health, and the tumor’s genetic profile.

Research and Advances

Ongoing research is crucial for improving glioblastoma outcomes. Some promising areas of research include:

  • Immunotherapy

    Using the body’s immune system to fight cancer. Researchers are exploring innovative approaches like combining oncolytic viruses with immune checkpoint inhibitors to enhance anti-tumor immune responses (Med Xpress) (BioMed Central).

  • Gene Therapy

    Targeting specific genetic mutations within tumor cells (ScienceDaily).

  • Oncolytic Virus Therapy

    Utilizing viruses that selectively infect and kill cancer cells. Recent studies have shown promising results with a combination of oncolytic viruses and immune-checkpoint inhibitors (Med Xpress).

  • Magnetic Resonance Guided Focused Ultrasound (MRgFUS)

    This technique is being investigated to disrupt the blood-brain barrier temporarily, allowing for more effective delivery of therapies (JHU).

  • Personalized Medicine

    Tailoring treatment based on the genetic makeup of the tumor. Advances in intraoperative imaging and molecular profiling are helping to define more precise treatment strategies (BioMed Central).

  • GBM in the News

    Latest updates and information curated by the Glioblastoma Research Organization. For the latest news and advancements, visit GBM in the News.

Living with Glioblastoma

Living with glioblastoma involves managing symptoms and maintaining quality of life. Supportive care services, including physical therapy, occupational therapy, and counseling, can help patients and their families cope with the challenges of the disease.

Citations

  • Louis, D. N., et al. (2016). The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary. Acta Neuropathologica, 131(6), 803-820.

  • Stupp, R., et al. (2005). Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. New England Journal of Medicine, 352(10), 987-996.

  • Johnson, D. R., & O’Neill, B. P. (2012). Glioblastoma survival in the United States before and during the temozolomide era. Journal of Neuro-Oncology, 107(2), 359-364.

  • Wen, P. Y., & Kesari, S. (2008). Malignant gliomas in adults. New England Journal of Medicine, 359(5), 492-507.

  • American Cancer Society. (2020). Understanding Cancer

Reviewed by Henry Friedman, MD - The Glioblastoma Research Organization Medical Advisory Board member.