Brain Cancer and Gliomas

Medically Reviewed by Dr. K on 28 April 2021

Brain Cancer and Gliomas

Glioma is a broad term for tumours of the brain and spinal cord that arise from the glial cells of the brain that support nerve cells.

Glioma symptoms, prognosis, and treatment are determined by the person's age, the specific type of tumour, and the tumour's location inside the brain. These tumours have a tendency for growing and infiltrating into normal brain tissue, making surgical removal tough, if not impossible, and complicating treatment.

Depending on the type of glioma, these brain tumours are often found in older adults. Males are significantly more likely than females to develop brain tumours. The majority of gliomas in children are low-grade.

Prior brain radiation is linked to the development of malignant gliomas. Some genetic disorders increase the likelihood of these tumours developing in children, but very occasionally in adults.

Malignant gliomas are not linked to any lifestyle risk factors. This includes consuming alcoholic beverages, smoking cigarettes, or using a mobile phone.

Types of Gliomas

Gliomas make up about 80% of malignant brain tumours, despite the fact that many benign brain tumours are gliomas.

Gliomas are named after the type of glioma or brain cell that is affected. Gliomas are classified as ependymomas, astrocytomas, or, oligodendrogliomas, according to the American Cancer Society.

  • Ependymomas account for less than 2% of all brain tumours in adults and less than 10% of all brain tumours in children. Since these tumours arise from ependymal cells and do not spread into normal brain tissue, some ependymomas can be surgically removed. They almost never spread outside the brain. They do, though, have a strong chance of local recurrence and are therefore classified as malignant.
  • Astrocytomas begin in brain cells and are called astrocytes. Since they spread across normal brain tissue, most of these brain tumours are incurable. Astrocytomas are typically identified by criteria developed by a doctor who examines a biopsy under a microscope. Grade 1 tumours develop the slowest, while grade 4 tumours, the most advanced, grow the fastest.
  • Oligodendrogliomas are tumours that behave similarly to astrocytomas in terms of spreading. Even though some of these tumours are slow-growing, they can also spread to surrounding tissue. They can sometimes be cured. Anaplastic oligodendroglioma of a higher grade grows and spreads more rapidly and is normally incurable.

Symptoms of a Glioma

Glioma symptoms are similar to those of other malignant brain tumours and vary depending on which part of the brain is impacted. Headache is the most common symptom, affecting roughly half of all people with a brain tumour. Seizures, memory loss, physical weakness, loss of muscle function, vision symptoms, language problems, cognitive deterioration, and personality changes are all possible symptoms. Depending on which part of the brain is affected, these symptoms may vary.

As the tumour grows and kills brain cells, compresses parts of the brain, and induces swelling and pressure in the skull, symptoms can worsen or change.

Diagnosis

A brain scan is only performed if a brain tumour is suspected. A CT scan, an MRI scan (which is deemed superior), or both may be used. If a brain scan reveals a tumour, a biopsy can be done to confirm the diagnosis. If surgery is an alternative for treatment, a biopsy may be performed at the same time as the tumour is extracted or separately.  Doctors may perform a treatment called stereotactic needle biopsy where a biopsy is performed separately, possibly because you are too ill or because the tumour is in a critical area of the brain. It involves sticking a needle through the skull into the brain to get a sample of the tumour.

Gliomas and Grading

Subtypes and a numerical grading system are used to classify gliomas. A tumour's grade refers to how cancer cells appear under a microscope. Grade I tumours develop slowly and may often be surgically extracted completely, while grade IV tumours grow quickly, are aggressive, and are challenging to treat.

Malignant astrocytomas are categorised and rated as follows, according to the latest World Health Organization (WHO) scheme:

  • Grade I gliomas involve pilocytic astrocytomas and children are more likely to have it.
  • Grade II tumours are diffuse astrocytomas and are low-grade.
  • Grade III gliomas are termed anaplastic astrocytoma since they are diffuse. They're known to be of high grade.
  • Grade IV glioblastoma is deemed high grade.

The following are the different types of oligodendroglial tumours:

  • Grade II or low grade oligodendroglioma
  • Grade III or anaplastic oligodendroglioma.

Subependymoma, ependymoma, and anaplastic ependymoma are the three types of ependymal tumours, with the latter being the most aggressive.

Low-grade tumours develop slowly, but they may progress to high-grade tumours.

Treatments

Based on the location of the tumour, the form of glioma (cell type), and the grade of malignancy, different treatment options for malignant glioma are considered. Treatment is often affected by the patient's age and physical condition. Glioma treatment may provide a variety of options, including:

  • Surgery is used to remove the tumour. The patient should be relatively healthy generally, with normal brain activity, speech, and mobility. To aid the surgeon in extracting the tumour, imaging techniques such as cortical mapping and functional MRI can be used. The goal is to remove as much of the tumour as possible while maintaining vital brain functions. tumour recurrences are very common.
  • Radiation therapy kills cancer cells by exposing them to high-energy X-rays or other forms of radiation.
  • Chemotherapy is a treatment that uses medications to stop cancer cells from growing. This therapy may be taken orally or injected.
  • Targeted therapy is a more recent therapeutic option that may help reduce tumours. It differs from chemotherapy in that it targets specific proteins that promote tumour growth.
  • Alternating electric field therapy uses magnetic fields to kill tumour cells whilst leaving healthy cells untouched. The electrodes are placed directly on the scalp. Optune is the name of the device. After surgery and radiation, it's given with chemotherapy. It has been approved by the FDA to be used in both newly diagnosed adults and adults with recurrent glioblastoma.
  • Corticosteroids, which decrease swelling in the brain produced by the tumour, and anticonvulsants, which suppress or prevent seizures, are forms of supportive therapy for improving symptoms and neurologic function.
  • Another choice is to participate in clinical studies to see whether new cancer therapies are successful and safe.
Treatment for Low-Grade Astrocytomas

Surgery is the most common treatment for low-grade astrocytomas. However, surgery may be complicated since these tumours reach far into the brain and grow into normal brain tissue. After surgery or where there is a recurrence, radiation is often recommended. Chemotherapy may also be used as a follow-up to surgery or to manage recurrences.

 
Treatment for High-Grade Astrocytomas

If possible, surgery is used to treat high-grade astrocytomas (Grade III anaplastic astrocytomas or Grade IV glioblastomas multiforme). Radiation therapy, in combination with chemotherapy, is the next phase after surgery. Some people can benefit from targeted therapy. Surgical removal of a high-grade tumour is not often feasible. Then there is radiation and chemotherapy. If the tumour reappears, the surgery, along with other types of chemotherapy, can be repeated. Patients will also be advised to participate in clinical studies in order to receive new therapies.

Treatment for Oligodendrogliomas

Surgery is the first option of treatment for oligodendrogliomas since it helps to alleviate complications and improve patient survival. After surgery, you may be offered radiation with or without chemotherapy. Even, before surgery, a tumour can be shrunk with chemotherapy or radiation. Chemotherapy with or without radiation therapy can be used if surgery is not an option.

Treatment for Ependymomas and Anaplastic Ependymomas

Ependymomas and anaplastic ependymomas, unlike other gliomas, rarely reach normal brain tissue. As a result, surgery can be very effective if the tumour is completely extracted. However, since ependymomas will seed the cerebrospinal fluid, MRI scanning of the entire spinal canal is required. Radiation has a strong response rate in these tumours.

Prognosis

High-grade gliomas are tumours that grow quickly. It carries a poor prognosis, especially for the elderly.

Sources

Referenced on 22.4.2021

  1. National Cancer Institute: “Adult Brain Tumors."
  2. National Cancer Institute: “What You Need to Know About Brain Tumors."
  3. American Cancer Society: “What are Brain and Spinal Cord Tumors?"
  4. Johns Hopkins Medicine: “Types of Gliomas."
  5. UpToDate: “Classification of gliomas."
  6. Ostrom, Q. Neuro Oncol., 2014
  7. Cern Foundation: “Ependymoma Statistics."
  8. World Health Organization: “The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary."
  9. American Cancer Society: “Alternating Electric Field Therapy for Adult Brain and Spinal Cord Tumors."
  10. U.S. Food and Drug Administration: “FDA approves expanded indication for medical devices to treat a form of brain cancer,” Oct. 8, 2015.
  11. https://www.webmd.com/cancer/brain-cancer/malignant-gliomas 

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