Brain Tumor

What is a brain tumor?

A brain tumor, also known as an intracranial tumor, is an abnormal mass of cells in or around the brain. The tumor can be cancerous (malignant) or noncancerous (benign). Tumors that are found in the brain and spinal cord are called central nervous system (CNS) tumors.

Both cancerous and noncancerous brain tumors can impact the way your brain works if they grow and press on surrounding tissues, nerves or blood vessels. Some tumors grow quickly and some grow slowly.

Are there different types of brain tumor?

Tumors that originate from the brain are called primary tumors (whether they originate from the brain cells or the surrounding tissues). If a tumor originates in a different part of the body and then spreads to the brain, it is called a secondary or metastatic brain tumor(s).

Primary tumors are classified as either malignant or benign, and are either:

• Glial: Made of the brain’s glial cells
• Non-glial: Develop in or on the brain’s structures such as blood vessels, glands or nerves.

Types of benign brain tumors include:

• Chordomas: Slow-growing tumors which usually form at the skull base.
• Craniopharyngiomas: Form in a part of the pituitary gland embryonic tissue.
• Gangliocytomas: Form in a specific nerve cells (neurons).
• Glomus jugulare: Form under the skull base at the jugular vein
• Meningiomas: Slow growing tumors which form in the tissue layers which protect the brain and spinal cord called the meninges.
• Pineal gland tumors: Form in the pineal gland, deep in the brain.
• Pituitary adenomas: Form in the pituitary gland at the base of the brain.
• Schwannomas: Form in the Schwann cells of the cranial nerves or peripheral nervous system.

Types of malignant brain tumors include:

• Astrocytoma: Forming in a type of glial cells called astrocytes, usually in the cerebrum, these are the most common type of glioma.
• Ependymomas: Form in the radial glial cells near the brain’s ventricles.
• Glioblastoma[KP1]: A fast-growing type of astrocytoma.
• Oligodendroglioma: Form in the oligodendrocytes (which insulate nerve cells within the brain).

What are the symptoms of a brain tumor?

The symptoms of a brain tumor can vary, depending on its size, location and type. If it’s very small, there may be no symptoms.

In general, brain tumor symptoms include:

• Balance difficulties
• Changes in personality
• Difficulty thinking or speaking
• Dizziness
• Feeling confused or disorientated
• Nausea or vomiting
• Numbness or tingling in the face
• Seizures
• Severe headaches
• Vision and hearing problems
• Weakness.

Always see a doctor if you experience any of the symptoms of a brain tumor.

What causes a brain tumor?

Brain tumors develop when specific genes become damaged and stop working properly. This damage means that brain cells don’t function the way they should, and abnormal brain cells, which grow and multiply quickly, form a mass of abnormal cells which take the space of normal cells.

Doctors don’t know exactly why this happens. Some changes in our DNA may be genetic, and some may be caused by environmental factors such as exposure to radiation from previous cancer treatments or X-rays.

How is a brain tumor diagnosed?

Diagnosing brain tumors can be complicated and requires the involvement of several specialists. Sometimes, a brain tumor may be found when imaging tests are performed for other medical issues.

If your doctor suspects a brain tumor, they will usually:

• Perform a physical examination.
• Discuss your symptoms in detail.
• Ask about any other health conditions, any family history of brain tumors, and medications you may be taking, and any past surgeries.
• Perform a neurological examination, which will assess your balance, reflexes, vision and mental status.

If a brain tumor is suspected, your doctor will perform the following to confirm a diagnosis:

• Brain scan: A magnetic resonance imaging (MRI) or computed tomography (CT) scan can identify a tumor’s size and location accurately. They can also show if a tumor has spread.
• Biopsy: A sample of the tumor is taken so that its type and malignancy can be determined. A biopsy may be done during surgery to remove part or all of the tumor. A stereotactic biopsy, in which a small hole is created in the skull and a needle used to take a sample of tissue, may be performed if the tumor is in a difficult to reach place.
• Spinal tap: Also known as a lumbar puncture, a doctor will take a sample of cerebrospinal fluid from the spine with a fine needle, which is examined for cancerous cells.
• Specialized tests: Blood or cerebrospinal fluid tests can identify tumor markers or gene abnormalities.

Pre-operative planning is a crucial part of successful treatment, and imaging technologies such as modern magnetic resonance imaging (MRI) and computed tomography (CT) scans provide invaluable information about a patient’s skull anatomy, as well as the location and behavior of a tumor.

Important technological advancements are now available that are helping in the diagnosis of certain types of brain tumors. These include:

• Advanced MRI techniques:

• Functional MRI (fMRI): An imaging technique which measures and maps brain activity by detecting changes associated with blood flow, helping to identify regions of the brain involved in various functions such as speech and motor function.
• Magnetic resonance spectroscopy (MRS): This provides chemical information about tissues, helping to differentiate between tumor types and grades.
• Diffusion tensor imaging (DTI): This maps white matter tracts in the brain, which is crucial for planning surgeries to avoid critical areas.

• Positron Emission Tomography (PET) scans:

• PET-MRI Fusion: Combining PET and MRI allows for detailed structural and functional imaging, improving tumor localization and characterization.
• Amino acid PET imaging: Enhances the detection of tumor boundaries and is particularly useful in cases where traditional imaging is inconclusive.

• Intraoperative MRI, CT, and ultrasound:

• Intraoperative MRI (iMRI) and intraoperative ultrasound: Allows surgeons to obtain real-time images during surgery, improving the precision and extent of tumor removal and minimizing damage to surrounding tissues.
• Intraoperative CT (iCT): Provides real-time imaging during surgical procedures, aiding in the accurate placement of surgical instruments and implants.
• Focus Ultrasound: This is a novel non-invasive technique can be used for the ablation of brain tumors and to increase the permeability of the blood brain barrier to facilitate the delivery of chemotherapy to the brain.

• Stereotactic techniques:

• Stereotactic biopsy: A minimally invasive procedure that uses three-dimensional coordinates to locate and safely biopsy brain lesions with high precision.
• Stereotactic radiosurgery (SRS): A non-invasive procedure using targeted radiation to treat tumors with high precision, sparing healthy tissues.
• Laser interstitial thermal therapy (LiTT): A minimally invasive procedure that delivers heat using a laser probe to destroy brain tumors or abnormal brain tissue causing seizures.

• Artificial Intelligence (AI) and Machine Learning: AI algorithms assist in analyzing imaging data and pathological specimens, enhancing diagnostic accuracy, and predicting treatment outcomes by learning patterns in large datasets.

• Liquid Biopsies: A non-invasive method to detect tumor-specific genetic material in the blood, which can provide insights into the genetic profile of the tumor and monitor treatment response.

How are brain tumors managed and treated?

Brain tumor or intracranial tumor treatment will depend on factors such as its size, location, type, number of tumors present and the patient’s overall health.

A combination of treatments may be used, including:

• Brain surgery: If possible, neurosurgery is performed to remove the tumor. Innovative technologies have transformed the way brain surgeries are performed in recent years, including:
  • Imaging technology: Incorporated into a navigation system and microscope during surgery, this allows for better visibility during the procedure.
    • Intraoperative neuromonitoring (IOM): Used to monitor the function of cranial nerves as well as overall brain function during surgery, it greatly increases success, leading to fewer side effects, better outcomes, and more complete removal of brain tumors.
    • Fluorescence guided surgery: A state-of-the-art method which uses special dyes and lamps to distinguish tumor tissue from adjacent brain tissue.
• Radiation therapy: High doses of radiation are used to destroy the brain tumor or shrink it. A type of radiation therapy, called brachytherapy, is sometimes used, which involves placing radioactive implants or seeds directly into or near the tumor.
• Radiosurgery: Focused beams of radiation are used to destroy the tumor, without an incision. Can also be applied in benign tumors.
• Proton beam therapy: A type of radiation therapy that uses protons instead of X-rays, offering more precise targeting of tumors, especially beneficial for tumors located near critical structures.
• Laser interstitial thermal therapy (LITT): A minimally invasive procedure using laser energy to destroy tumors, often used for tumors that are difficult to access surgically.
• Chemotherapy: Drugs are given which kill cancerous cells. Chemotherapy may be given after surgery to ensure all cancer cells have been killed.
• Immunotherapy: This therapy uses the body’s own immune system to attack cancer cells.
• Targeted therapy: Drugs are given which target certain features of the cancer cells, but don’t affect healthy cells.
• Active surveillance: If the brain tumor is benign and very small/causes no symptoms, doctors may suggest closely and regularly monitoring it.

Many brain tumors are benign but may still affect the way your brain works and may require medical treatment. If you experience any of the symptoms listed above, always talk to your doctor.