A brain tumor is an abnormal growth of cells that develops in the brain or in areas close to it. These tumors can form within the brain tissue itself or in nearby structures such as nerves, the pituitary gland, the pineal gland, or the membranes that cover and protect the brain.
What is a brain tumor?
Brain tumours are abnormal masses that develop in the brain due to uncontrolled cell growth and division.
There are over 150 different types of brain tumours. Some are benign (non-cancerous), while others are malignant (cancerous). They are generally divided into two main categories:
- Primary brain tumours originate within the brain itself. They may develop from brain cells, the meninges (membranes surrounding the brain), nerves, or glands.
- Secondary brain tumours form when cancer from another part of the body, such as the breast or lungs, spreads to the brain. These are also called metastatic brain tumours and are more common than primary brain tumours.
Whether benign or malignant, brain tumours can increase pressure inside the skull, disrupt normal brain function, and lead to various health complications.
Common symptoms of brain tumor
The signs and symptoms of a brain tumour vary depending on its size, location, and how quickly it is growing, which is referred to as the tumour grade.
Common signs and symptoms of brain tumours may include:
- Headaches or a feeling of pressure in the head, especially in the morning
- Headaches that become more frequent or more intense over time
- Headaches that may feel similar to tension headaches or migraines
- Nausea or vomiting without a clear reason
- Vision problems, such as blurred vision, double vision, or loss of side vision
- Weakness or loss of sensation in an arm or leg
- Difficulty maintaining balance or coordination
- Problems with speaking or understanding speech
- Persistent fatigue or unusual tiredness
- Confusion during routine activities
- Memory difficulties
- Trouble understanding or following simple instructions
- Changes in personality or behaviour
- Seizures, particularly in individuals with no prior history of seizures
- Hearing difficulties
- Dizziness or a spinning sensation, known as vertigo
- Increased appetite and unexpected weight gain
Causes of brain tumours
Brain tumours that develop from cells within the brain are known as primary brain tumours. These tumours may begin in the brain tissue itself or in nearby structures, such as the meninges (the protective membranes covering the brain), nerves, the pituitary gland, or the pineal gland.
Primary brain tumours occur due to changes or mutations in the DNA of brain cells. DNA contains instructions that regulate how cells grow, function, and die. When these instructions are altered, cells may grow rapidly and avoid the natural process of cell death. This leads to the accumulation of abnormal cells, which can form a tumour. As the tumour grows, it may invade or damage surrounding healthy brain tissue.
In many cases, the exact cause of these DNA changes is unknown. However, some brain tumours are linked to inherited genetic mutations passed down from parents to their children, although hereditary brain tumours are uncommon. Individuals with a family history of brain tumours may benefit from consulting a healthcare professional or genetic specialist to assess their risk.
Brain tumours in children are more often primary, meaning they originate in the brain. In contrast, adults are more likely to develop secondary brain tumours, which occur when cancer from another part of the body spreads to the brain.
Types of brain tumors
Brain tumors are classified into different types based on their origin and nature.
Primary Brain Tumors
- Originate in the brain or nearby tissues
- Examples include gliomas, meningiomas, and pituitary tumors
Secondary Brain Tumors
- Result from cancer spreading to the brain from other parts of the body
- Commonly caused by lung, breast, or kidney cancer
Benign Brain Tumors
- Non-cancerous and slow-growing
- Typically do not spread to other parts of the body
Malignant Brain Tumors
- Carncerous and aggressive
- May invade nearby tissues or spread to other parts of the body
How are brain tumors diagnosed?
Diagnosing a brain tumor involves various medical tests and evaluations. Common methods include:
- Neurological exam: Tests reflexes, balance, and coordination to detect abnormalities.
- Imaging tests: MRI and CT scans help identify the tumor’s size and location.
- Biopsy: Involves sampling the tumor tissue for detailed analysis.
- Blood tests: Detects markers that may indicate a tumor's presence.
What are the risk factors for brain tumours?
Several factors may increase the risk of developing brain tumours, although having one or more risk factors does not guarantee that a tumour will occur. These include:
- Age: Brain tumours can occur at any age, but certain types are more common in children, while others are more frequently diagnosed in older adults.
- Family history and genetic conditions: In rare cases, inherited genetic disorders such as neurofibromatosis, Li-Fraumeni syndrome, or tuberous sclerosis can increase the risk.
- Exposure to radiation: Previous exposure to high levels of ionising radiation, especially radiation therapy to the head during childhood, is one of the strongest known risk factors.
- Weakened immune system: People with compromised immunity, such as those with HIV/AIDS or those who have undergone organ transplants, may have a higher risk.
- History of cancer: Individuals who have had cancer in other parts of the body may develop secondary (metastatic) brain tumours if cancer spreads to the brain.
- Environmental exposure: Long-term exposure to certain toxic chemicals or harmful substances may also contribute, although research is ongoing.
What are the complications and related diseases of brain tumours?
Even benign brain tumours can continue to enlarge over time, raising the pressure inside the skull (intracranial pressure). This increased pressure can interfere with vital brain functions and disrupt normal body processes. In severe cases, it may lead to serious complications such as hydrocephalus (a buildup of fluid in the brain) or brain herniation, both of which can be life-threatening and may result in coma or even death.
