Brain tumours: how are they diagnosed and what treatments may be offered?

Very different tumours

A first distinction is made between primary tumours, which arise in the brain or its coverings, and metastases, which come from a cancer located elsewhere, for example in the lung, breast or skin. Among primary tumours:

• gliomas arise from the supporting cells of the brain; their aggressiveness ranges from slow-growing forms to rapidly progressive forms such as glioblastoma;
• meningiomas arise from the coverings of the brain; most are benign;
• pituitary adenomas can disturb hormones or compress the nerves of vision;
• schwannomas, such as that of the hearing nerve, are benign tumours of the nerves;
• in children, other tumours predominate, with specific paediatric care.

Since 2021, the World Health Organization classification has included molecular markers in the diagnosis of many tumours of the nervous system. Two tumours that look alike under the microscope may therefore have a different prognosis and treatment.

Which symptoms should prompt a consultation?

Symptoms depend more on the size and location of the tumour than on its nature:

• recent, progressive headaches, often in the morning, sometimes with vomiting;
• an epileptic seizure in someone who has never had one;
• weakness on one side of the body, a disturbance of speech, vision or balance;
• changes in behaviour, memory or concentration;
• hormonal or visual disturbances for tumours in the pituitary region.

Sudden worsening, increasing drowsiness, repeated vomiting or a prolonged seizure require emergency care.

Diagnosis: from MRI to tissue sample

Contrast-enhanced MRI of the brain is the reference test. It locates the tumour, measures its volume, shows the swelling around it and points towards a probable type. CT is often carried out first in an emergency. When a metastasis is suspected, an assessment looks for the original cancer.

In most cases, the diagnosis is confirmed by analysis of tissue obtained during a biopsy or surgical removal. The pathologist specifies the type, the grade and the molecular markers. For some tumours, such as small typical meningiomas, monitoring without a sample may be offered.

What treatments?

Surgery

When possible, removing the tumour aims to take out as much tumour tissue as possible without damaging the areas essential for movement, speech or vision. It relieves compression and provides the tissue needed for diagnosis. Depending on the location, a biopsy alone may be preferred.

Radiotherapy and radiosurgery

Fractionated radiotherapy delivers daily sessions over several weeks; it often follows surgery for aggressive tumours. Stereotactic radiosurgery, for example with Gamma Knife, concentrates a high dose in one or a few sessions on a small, well-defined target, such as certain metastases or certain meningiomas.

Medicines

Depending on the type of tumour, chemotherapy, sometimes combined with radiotherapy, or targeted treatment may be offered. Corticosteroids reduce swelling around the tumour and anti-epileptic drugs prevent seizures when necessary; these supportive treatments must not be stopped without medical advice.

After treatment

Follow-up relies on regular MRI scans, the frequency of which depends on the type of tumour and the treatment received. Rehabilitation, support for cognitive or mood problems and management of fatigue are part of care. A summary document stating the diagnosis, the treatments and the MRI schedule is essential for the doctor providing follow-up in the home country.

Frequently asked questions