Definition & Overview
Meningiomas are classified as brain tumours that grow from the meninges, which are fibrous membranes that protect delicate tissues of the central nervous system. The majority of meningiomas cases are slow-growing and benign (non-cancerous) but can still cause serious complications depending on their location or size. Meningiomas are more likely to affect women than men and may appear at any age. However, when they appear in men, they are highly likely to be malignant. In women, they are common between the age of 50 and 70. Based on research, the condition is prevalent in all cultures and has the same statistical frequency as other types of brain tumours. Meningiomas are very rare in children.
Cause of Condition
Despite the advancement in the field of cancer research, the causes of meningioma are yet to be established. However, experts believe that the condition stems from abnormalities in the cells in the meninges causing them to multiply rapidly.
Most cases of meningiomas are sporadic while some are familial. Although the exact causes are yet to be identified, experts have come up with a list of risk factors, which include the following:
- Radiation treatment
- Previous brain injury
- Frequent dental X-rays
- Heavy mobile telephone use
- Neurofibromatosis (an inherited nervous system disorder)
- Female hormones – as meningioma is more common in women, experts believe that female hormones may play a role in its development.
- Genetic mutations particularly on chromosome 22q
Being slow-growing tumours, meningiomas typically don’t show signs and symptoms during the early stages, making early detection close to impossible. In fact, thousands of individuals remained undiagnosed, with the condition being discovered only during an autopsy. About two percent of all autopsies reveal the presence of meningioma, which remained unknown to the individuals during their lifetime, as they did not notice any symptom of the condition. In the 1970s, two out of 100,000 people were diagnosed with the condition following the appearance of the symptoms while 5.7 out of 100,000 were diagnosed despite the absence of the symptoms. In recent years, diagnosing asymptomatic meningiomas has increased by up to 300% due to the availability of modern imaging technologies such as CT scans.
Meanwhile, patients who were diagnosed with the condition exhibited the following symptoms:
- Memory loss
- Blurred vision
- Chronic progressive headaches
- Loss of smell
- Weakness in the arms and legs
- Speech problems
If patients are showing symptoms listed above, a brain scan will most likely to be performed, allowing the doctor to identify the location and assess the size of the meningioma.
Who to See & Types of Treatment Available
The first medical professional to see when experiencing symptoms that are closely associated with meningioma is a general practitioner or family doctor who can perform a thorough physical examination and review your medical history before ordering a CT scan or an MRI. If meningioma is confirmed, you will be referred to specialists. Depending on the severity of the condition, you will require the expertise of a team of doctors that is composed of neurosurgeons, radiation oncologist, and your primary health provider.
Meningiomas are classified into three types:
Grade 1 – 75% of all meningiomas fall under this category, which is characterized by the presence of benign, slow-growing tumours that may not need treatment.
Grade 2 – These are also slow-growing tumour but are likely to recur.
Grade 3 – These are malignant tumours that are growing at a fast rate and producing symptoms listed above.
Prior to initiating treatment, the neurosurgeon will perform different tests to assess the extent of your condition and identify any medical problems that you may have. Treatment protocols, which can include radiation therapy, surgery, and chemotherapy, aim to remove the tumours to relieve pressure and prevent the distortion of the normal brain tissue.
However, if various tests confirm that the tumour is not causing any problem and is highly unlikely to spread and cause life-threatening complications, observation is often recommended. This option requires regular brain scans to confirm that the tumour is not growing. It the tumour grows or if symptoms start to develop, the neurosurgeon will recommend surgery. In cases where the tumour is not accessible, radiation therapy will be used to shrink the tumour and at the same time, kill cancer cells. In cases where the surgeon is unable to remove 100% of the growth, surgery will be combined with radiation therapy to ensure that no traces of the tumour or cancer cells are left behind.
Radiosurgery is another treatment option performed by aiming beams of powerful radiation at precise locations, making sure that surrounding structures and tissues are unharmed. This treatment, despite its name, does not require surgery and is performed in cases where the surgeon is unable to remove the tumour via traditional surgical approach and when the tumour keeps on recurring despite treatment.
If the tumour is located near the optic nerves and if high-intensity radiosurgery is deemed to do more harm than good, fractionated radiation is often recommended. This treatment requires several sessions where the patient receives small fractions over time. For patient’s safety and to ensure the success of the treatment, each session is spaced 30 days apart.
Certain medications can also be used to treat meningioma. This is typically the best option for tumours that do not respond to other forms of treatment including surgery and radiation. One of the commonly prescribed drugs is hydroxyurea. Drugs such as somatostatin analogs are also being tested to prevent the release of growth hormones.
Medications are also provided to control symptoms. These include anticonvulsant drugs to prevent seizures and steroid drugs to relieve swelling. During the course of treatment, a thin, plastic tube may also be surgically placed to drain the fluid from the brain.
- Cedars-Sinai: "Meningiomas Brain Tumors."
- Brigham and Women's Hospital: "Facts about Meningiomas."
- Johns Hopkins Medicine web site: "Grades of Meningioma," "Stereotactic Radiosurgery," "What Is a Meningioma?" "Types of Meningioma," "Diagnosis of Meningioma," "Treatment of Meningioma."
- American Academy of Neurological Surgeons: "Meningiomas."
- Medscape: "Pathophysiology."
- UCLA Health System web site: "What Is a Meningioma?"