By Wesley M Jose
Brain tumour is a common term to describe all the cancers that can affect the brain. Brain can have primary tumours, which means the tumour begins in the brain, or secondary tumors (also known as metastatic) which have started elsewhere but have now migrated to the brain.
Conventionally, the term brain tumour is indicative of primary brain tumour. All brain tumours are not malignant. Some may be slow-growing and benign. But even the tumor that is slow growing may invade into other nearby structures and cause symptoms.
These tumours may arise from different parts of the brain — for example, the tumour arising from meninges, which is the covering layer of the brain, is called meningioma; or gliomas, which arise from the supporting cells of the brain called glia. The World Health Organization (WHO) classifies primary tumours into low grade (grade 1 and 2) and high grade (grade 3 and 4).
What Causes Brain Tumour?
Brain tumours arise due to abnormal genes and chromosomes, which lead to uncontrolled growth and increase of a particular kind of cell in the brain. The affected genes are primarily related to control of cell growth, repair of the damaged cells and senescence (meaning cells getting old and dying). An intrinsic loss of control on cell multiplication, inability to repair the damaged non-functional cell and ability of the damaged cells to continue living instead of self-destructing (becoming immortal) is the primary reason for occurrence of these tumours.
Such gene abnormality may be genetically inherited from parents or may be acquired later in life. A well known acquired factor for brain tumors is exposure to radiation like in blood cancer treatment of children where radiation to the brain is a part of treatment. Such tumours arise 10-15 years after the radiation exposure.
Most people with brain tumours do not have any family history but in rare situations the tumours may be familial. If you have a close family member (related by blood) who has a diagnosis of neurofibromatosis, tuebrous sclerosis, von-hippel landau sybndrome, Li fraumeni, turcot syndrome, Lynch syndrome, then you too may be at risk.
Lately there have been debates about use of cellular phones causing brain tumours. The cell phones produce radiofrequency waves and not ionising radiation (which causes cancer). The available medical data from large studies does not support this association. However, if you are concerned, it would be prudent to avoid long use of cellular phones.
Similar to cell phones, living near high-tension power lines (producing string electromagnetic fields) has also been blamed but is yet unproven.
The other environmental factors that have been blamed for causing brain tumors are petroleum products, vinyl chloride which is used in plastic manufacture.
Using sugar substitute called aspartame, infection by certain viruses have also been suggested as possible risk factors. But there is no foolproof evidence for the same.
Brain Tumour Prevention And Symptoms
Since there are no specific proven environmental factors that cause primary brain tumour, it may be difficult to make standard guidelines for prevention of brain tumour. This means the emphasis still remains in knowing whether you have a family history in which case you could do germline testing to identify whether you are at risk.
If you do not have a family history, it is best to approach a hospital if you have any unexplainable symptoms which you consider needs attention. The best person to approach for a brain-related issue may be a physician or neurologist who has reasonable means to evaluate you.
While symptoms may vary depending on the location of the tumour, these are some of the signs that should prompt you to see a doctor:
- Severe headaches in the morning, or if it wakes you up at night
- Seizures or convulsions
- If you find it difficult to think, speak or articulate. Confusion and disorientation
- Weakness or paralysis in one part or one side of the body
- Dizziness or loss of balance
- Changes in vision and/or hearing
- Tingling or numbness on face
- Nausea or vomiting, difficulty swallowing
The author is Associate Professor (Lead Neuro-oncology Services), Medical Oncology, AIMS Kochi
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