Brain cancer refers to a set of conditions in which abnormal cells develop in the brain tissue or coverings of the brain. These may include primary brain cancers (that begin in the brain) or secondary brain cancers (resulting from cancer elsewhere spreading to the brain).

It’s important to note that not all brain tumours are cancerous (malignant); some are benign (non-cancerous) and grow slowly, but may still affect brain function because of location and pressure.

Because the brain is encased in the skull and contains vital structures, any growing mass—even a non-cancerous one—can have significant effects.

If you have concerns or questions about possible brain cancer, the best step is to consult a specialist who can explain what tests may be indicated and what your situation is.

Signs are indications that something may be changing in brain function or structure. While signs alone do not confirm a brain cancer diagnosis, they can be prompts to further medical review. Common signs include:

• Persistent or worsening headaches, particularly if worse on waking or when bending/straining.
• Seizures, new onset or change in pattern.
• Changes in behaviour or personality, such as increased irritability or lack of interest in usual activities.
• Weakness, numbness or loss of movement on one side of the body.
• Difficulty walking, balance problems, dizziness or unsteadiness.
• Vision, hearing or speech problems, new or worsening.

These signs are not exclusive to brain cancer—they may have many other causes. But if you notice a new, persistent, or worsening sign, it’s helpful to seek medical review.

Unlike many other cancers, the concept of “stage” (how far the cancer has spread) is less straightforward for many primary brain cancers. For brain tumors, doctors often refer to grades (which reflect how abnormal the cells look and how quickly they may grow) rather than the same staging system used for other cancers.

For example:

• Grade I or II = lower grade, slower-growing, often more benign-behaving.
• Grade III or IV = higher grade, more aggressive tumor behavior.

It’s still important to understand that each case is unique: tumor location, type, size, patient health and other features all affect how disease is managed and what outcomes might look like. Always rely on a specialist’s evaluation for how disease is described in your specific situation.

Symptoms are the changes a person may experience because of a brain tumour pressing on or damaging brain tissue, causing increased intracranial pressure or interfering with normal brain function. Common symptoms may include:

• Headaches that may be worse in the morning or when bending, coughing or straining.
• Nausea or vomiting, particularly if associated with headaches.
• Seizures or convulsions, or subtle changes in consciousness or awareness.
• Weakness or numbness in part of the body, loss of coordination, difficulty with walking or balance.
• Changes in vision (blurry or double vision), hearing or speech.
• Memory problems, difficulty concentrating, confusion or personality change.

Again, these symptoms do not automatically mean brain cancer, but when they appear newly or worsen, they may warrant investigation.

The brain can be affected by many different tumor types. Some of the better-known types include:

• Gliomas — tumors that develop from glial (support) cells in the brain. These include sub-types such as astrocytoma, oligodendroglioma and glioblastoma.
• Astrocytomas — start in astrocytes (a kind of glial cell). These range from lower grade to higher grade (glioblastoma is a high-grade astrocytoma).
• Oligodendrogliomas — develop from oligodendrocytes (another glial cell type). Often slower-growing but still significant.
• Ependymomas — arise from ependymal cells lining brain cavities and spinal cord canals.
• Meningiomas — tumors that originate from the meninges (the membranes covering the brain and spinal cord). Many are benign but can cause effects by location.
• Other rarer types: embryonal tumors (more common in children), pineal-region tumors, nerve-sheath tumors, etc.

Each type has its own behavior, growth potential and implications. The classification and naming of these tumors has evolved over time as genetic testing has advanced.