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types of cancer

Brain Tumour

Overview

A Brain Tumour is defined as an abnormal growth of brain cells (neural or connective cells) which can be malignant (cancerous) or benign (non-cancerous). The suspicion of a brain tumour may arise from headaches, abnormal behaviour or a variety of other symptoms. The symptoms require an investigation with a series of tests.

Symptoms

The symptoms of brain tumours vary widely depending on the type and location of the tumour. Some of the most common symptoms are headache, vomiting or nausea. These are often caused by increased intracranial pressure. The tumours can also encroach and compress the surrounding brain tissue giving rise to additional symptoms like drowsiness, seizures and insomnia. Abnormal behavioural changes amongst children can be associated to brain tumour.

Symptoms associated with the main parts of the brain may include one or more of the following:

  • Frontal lobe memory loss
  • Impaired sense of smell and loss of vision
  • Behavioural, emotional and cognitive changes
  • Impaired judgment
  • Parietal lobe impaired speech
  • Inability to write
  • Occipital lobe vision loss in one or both eyes
  • Temporal lobe impaired speech
  • Seizures
  • Brainstem irritability
  • Difficulty in swallowing
  • Drowsiness and headaches in the morning
  • Muscle weakness on one side of the face or body
  • Drooping eyelid or crossed eyes
  • Increased Intracranial Pressure (ICP)
  • Vomiting (usually occurs in the morning without nausea)
  • Uncoordinated muscle movements
  • Problems walking (ataxia)
  • Causes

    The causes of brain tumours are largely unknown. However the risk of brain tumour is higher among people who have suffered from or have had exposure to:

    • Genetic cell mutations
    • Viruses that can affect the brain
    • Injury to the head
    • Exposure to harmful chemicals
    • Radiation
    • Hormone imbalance and/or hormone based therapy
    • Environmental factors
    • Occupational factors

    Brain tumours are not contagious. It is however clear that a large portion of brain tumours are caused by other cancers. Patients who have had any history of cancer in their childhood are prone to getting brain tumours. Such tumours are called secondary brain tumours.

    Diagnosis

    Neurological examination: This helps to establish the Increased Intracranial Pressure and the focal deficit would help us localise the probable site of tumour.

    Magnetic Resonance Imaging (MRI): MRI is perhaps the most valuable test used to diagnose brain tumours because it provides an accurate anatomical location of the tumour along with proximity to important areas (DTI and functional MRI) and probable pathology of the tumour (with the help of spectroscopy / perfusion studies).

    Computed Tomography (CT): The CT is an affordable method for effective detection of tumour. It is most effective while detecting lesions with calcification or blood in the lesion.

    Benign tumours are often extra-axial in location. Surgery is the only treatment for benign tumours and the duration depends on the complexity of the tumour.

    There are times when the surgeon may not be able to treat the tumour effectively due to its complexity and location. In such cases additional radiotherapy or radiosurgery may have to be considered as adjuvant therapy. In certain instances where tumour has formed in the membranes that cover the brain (Meningioma), then surgery is advised.

    Malignant brain tumours can be slow or fast-growing and is usually life threatening due to their ability to invade and destroy surrounding normal brain tissue. There are two types of malignant brain tumours known as primary and metastatic. Primary brain tumours originate from the cells in the brain and they include various sub-types. The most common type of malignant primary brain tumour is Glioblastoma Multiforme (grade IV astrocytoma), which make up approximately 20% of all primary brain tumours. Glioblastoma is quite common amongst elderly patients. Metastatic brain tumours are cancers that have spread from other areas of the body to the brain. There are cases where brain tumour is common in patients with metastatic melanoma (cancer which develops in the pigment containing cell called melanocytes). These tumours are the most common, occurring as much as four times more frequently than primary brain tumours. Cancers that commonly spread to the brain include breast and lung cancers. The prognosis depends on the grade of the malignant tumour.

    Generally grade 1 or pilocytic tumours (common amongst children) behave like a benign tumour which need long-term follow up. In the present era the outlook of the disease has improved with the use of immune histology, tumour marker, modern radiotherapy technique and less toxic chemotherapy.

    Treatment

    Brain tumours are typically treated with surgery, radiation therapy and chemotherapy. Sometime a combination of all three options is exercised as part of the standard procedure.

    Surgery is the primary treatment for brain tumours that can be removed without causing severe damage. Many benign tumours are treated only by surgery but most malignant tumours require treatment along with surgery, such as radiation therapy and/or chemotherapy.

    The goals of surgical treatment for brain tumours are multiple and may include one or more of the following:

  • Remove all or as much of the tumour as possible
  • Reduce symptoms and improve quality of life by relieving intracranial pressure caused by the tumour
  • Provide access for implantation of internal chemotherapy or radiation
  • A stereotactic or navigation guided biopsy is used to access the tumour in deep seated areas where surgery is hazardous. This technique utilises a computer and a three-dimensional scan to direct the placement of the needle. Radiation Therapy (RT) may be used alone or in combination with surgery and/or chemotherapy while treating primary or metastatic brain tumours. External Beam RT is the conventional technique for administering radiation therapy for brain tumours. Another treatment method includes using the CyberKnife System which involves a frameless robotic radiosurgery system for treating benign tumours, malignant tumours and other medical conditions.

    The CyberKnife system is a method of delivering radiotherapy with the intention of targeting treatment more accurately than standard radiotherapy. This system improves on other radiosurgery techniques by eliminating the need for stereotactic frames. As a result, this methodology enables doctors to achieve a high level of accuracy in a non-invasive manner and allows patients to be treated on an outpatient basis. The CyberKnife system can pinpoint a tumours’ exact location in real time using X-ray images to capture the unique bony structures of a patient’s head. It has a strong record of proven clinical effectiveness. It is used either on a stand-alone basis or in combination with chemotherapy, surgery or whole brain radiation therapy.

    Treating brain tumours with chemotherapy is more complicated than treating tumours elsewhere in the body because of a natural defence system called the blood-brain barrier that protects the brain from foreign substances. Furthermore, not all brain tumours are sensitive to or respond to chemotherapy, even if the drug does penetrate the blood brain barrier. Actively dividing cells are the most vulnerable to chemotherapy. Most tumour cells and some normal cells fall into that category. In cases where lymphoma has started in the brain (cerebral lymphoma), chemotherapy becomes a possible option. The side effects of chemotherapy can include nausea, vomiting, mouth sores, loss of appetite and loss of hair.

    Some of the latest methods for treating brain tumours include:

    Chemotherapy wafers – the wafers contain cancer killing substances which is inserted directly into the area of the brain tumour during surgery. The wafers are effective in reaching out to remote regions of the brain.

    Immunotherapy is a breakthrough innovation in cancer care where the immune system is strengthened to fight against cancer.

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