A primary brain tumour means that the first site of occurrence is in or around the brain, rather than being a secondary occurrence resulting from another form of cancer. Meningioma can however also occur as a secondary tumour, metastasising from breast cancer for example. 

Previous radiotherapy to the head, for example to treat paediatric (childhood) cancer, may cause meningioma to develop a number of years after the initial treatment.

Meningioma can also occur as part of a genetic condition, Neurofibromatosis 2 (NF2).

The incidence of meningioma increases with age and there is a notable increase after the age of 65.

Meningioma are nearly twice as common in females than in males, rising to being three times more common in females between the ages of 35 and 54 years.

A drug called Cyproterone Acetate (CPA) that acts on testosterone and is used in the treatment a number of medical conditions. When used in very high doses, for example to control aggressive sexual disorders or support transgender women, CPA has been shown to induce meningioma. If the CPA is stopped, these meningioma tumours usually shrink and there is no need for any further treatment. It is therefore very important that you disclose to your medical team if you are taking CPA and have been diagnosed with a meningioma.

Estrogen-only hormone replacement therapy (HRT) has been linked to a small increased risk of developing a meningioma, but estrogen-progestin hormone therapy has not.

There are actually over 50 different sub groups of meningioma, but the World Health Organisation (WHO) groups them into three grades to reflect their main characteristics:

Grade I is the least aggressive and slowest growing form of meningioma, therefore carrying the longest prognosis. This form may never grow back after a successful surgical operation that is able to remove all, or most, of the tumour. Some meningioma may never grow any bigger and will not need to be treated at all, so the first line of response from your medical team may be to simply keep the tumour under close surveillance (for example by offering you a scan every 6 or 12 months), but not to treat until it poses a threat due to its size, position or a worsening of your symptoms.

Grade II meningiomas are known as “atypical meningioma.” Their name indicates the fact that these do not behave in a “typical” way and therefore their rate of growth and recurrence is hard to predict, but they are more likely to recur after surgery than a grade I meningioma. If you have a grade 2 meningioma you will be carefully monitored by your medical team to ensure that you receive the best possible care.

Grade III meningiomas are known as anaplastic (malignant) meningioma, and represent approximately 3% to 5% of those diagnosed. Unfortunately, these frequently recur after surgery, which is why they are also treated with radiotherapy.

Methylation means adding, removing or replacing a methyl group (CH3) on a molecule (for example, DNA) that then influences the way in which molecules behave (for example, switching genes on the DNA on and off). Molecular profiling can potentially be used to predict which tumours are more likely to progress to a higher grade or recur after surgery, so there is a lot of research in this area at the moment to clarify which molecular markers can be relied upon to predict how a tumour will behave, and hence guide treatment decisions as well as offer opportunities to develop drugs that influence those molecules’ behaviour.

Higher grades of meningioma have larger numbers of genetic changes than lower grade tumours, which makes them more aggressive and harder to treat.

This knowledge helps medical teams to plan how aggressively they need to treat a tumour, or if it is safe to choose active monitoring: meaning regular scans and blood tests that will indicate when is the best time to treat. It also enables researchers to explore drugs that can target specific genetic mutations, leading in the future to more effective, personalised treatment protocols.

NF2 is the gene which when mutated gives rise to a condition called Neurofibromatosis 2, an inherited genetic disorder characterized by the development of schwannoma, ependymoma and meningioma tumours in the brain and spinal cord. Approximately 40% - 60% meningiomas have a mutation of the NF2 gene although this does not necessarily mean that the patient has Neurofibromatosis 2. If you were diagnosed with Neurofibromatosis 2 you would be directed to a specialist team to care for you.

The signs and symptoms may include:

• Changes in vision, such as blurriness or seeing double 
• Headaches that worsen with time
• Hearing loss or tinnitus (ringing in the ears)
• Memory loss
• Loss of smell
• Seizures
• Weakness in the arms or legs

Symptoms are primarily caused by the meningioma growing to a size that puts pressure on parts of the brain or spine nerves and blood vessels. This is especially true if the tumour is growing inwards rather than spreading close to the skull.

Surgery

Some meningiomas can be successfully removed by surgery, whilst others may be in positions that make complete removal impossible. For example, the tumour may be wrapped around the optic nerve or an artery. In these cases, the priority for the neurosurgeon will be to remove as much of the tumour as possible whilst avoiding damage to any critical structures within the brain.

If the tumour grows back, surgery may be offered again to reduce tumour size 

Radiotherapy

After surgical removal, some meningioma may grow back. For this reason, those classified as grade II or III will be treated with radiotherapy in order to reduce the risk of this re-growth happening. 

Some tumours are treated with stereotactic radiosurgery, which is a tightly focused type of radiotherapy, usually given in one high-dose session. This is a contrast to the way in which fractionated radiotherapy is delivered, which is in lower doses spread over a number of appointments.

Chemotherapy

Chemotherapy is rarely used for meningioma tumours because they grow so slowly, and most chemotherapy drugs are designed to target cells that are dividing rapidly, as seen in more malignant (faster growing) forms of cancer.

More details about the current standard of care for meningioma can be found in the NICE guidance document here.

Our University of Plymouth Low-Grade Brain Tumour Research Centre of Excellence is Europe’s leading research institution for low-grade brain tumours, and has a strong focus on meningioma. They have a large bank of meningioma samples and have identified a wide variety of genetic mutations across all grades. This has enabled them to develop a blood test that can identify different subgroups of meningioma, with the potential to be used as a way to classify and monitor tumours without the need for a surgical biopsy. They are also developing and testing a range of drugs for meningioma, including those caused by the genetic condition Neurofibromatosis 2 (NF2).

The team of research and clinical experts at our Centre of Excellence at Imperial College, London have built up a significant bank of meningioma tissue samples thanks to their close relationship with Charing Cross Hospital. They work closely with the University of Plymouth Centre of Excellence on certain aspects of research into meningioma, particularly the identification of genes and proteins that can form potential targets for drugs to influence. 

Scientists at our Centre of Excellence in the University of Portsmouth have identified a number of proteins that are expressed (activated) in Grade I meningioma, but are not expressed in healthy brain tumour cells. Such findings can potentially be used to develop treatments that target theses proteins and hence influence the processes that they control.

Pioneering research at our Brain Tumour Research Centre of Excellence at Queen Mary University of London has developed methods of studying stem cells that could potentially transfer across all types of brain tumour.

We also fund BRAIN UK at Southampton University, the country’s only national tissue bank providing crucial access to brain tumour samples for researchers from the archives of clinical neuroscience centres in the UK, effectively covering about 90% of the UK population, and an essential component in the fight to find a cure for meningioma.