Meningioma – curable or dangerous?

Meningiomas are among the most common benign brain tumors. Meningiomas often only cause symptoms when they have reached a certain size. Meningiomas rarely grow quickly and aggressively.

Accidentally discovered (incidental) small meningiomas are increasingly being diagnosed, as powerful MRI imaging of the head is increasingly used in the case of non-specific neurological complaints or when staging cancer.

Patients and the caring team of doctors must then discuss how to proceed together. The balance between “observation” and immediate therapy often represents a challenge for everyone involved.

Meningioma profile

Meningiomas originate from cells of the middle soft meninges (arachnoid membrane).

• Every year, around 9 out of 100,000 people develop a new meningioma (incidence).
• The incidence increases with age. Meningiomas often occur between the ages of 60 and 70.
• Women are affected slightly more often than men.
• Most meningiomas occur in the skull (intracranial), but rarely in the area of ​​the spine (spinal).

Symptoms: If meningiomas cause symptoms, they can often initially be unspecific. Headaches or epileptic seizures are typical. Further neurological deficits depend primarily on the location of the meningioma.

Diagnosis: The gold standard for diagnostics is MRI. If there is clear evidence of a benign tumor, a biopsy can be avoided.

Therapy: Standard treatment for a symptomatic meningioma is the complete surgical removal of the tumor including the affected structures such as the meninges or skull bones. Alternatively, meningiomas can also be irradiated. The disadvantage: a final histological examination is then not possible.

Mostly benign and curable in the long term

The vast majority of meningiomas are benign tumors and, when the tumor tissue is examined, are classified histologically as WHO grade 1 tumors. They usually grow very slowly, are sharply defined and have a broad base on the hard meninges (dura mater). They are either initially observed, operated on or given stereotactic radiation and have a good prognosis. Complete removal of a benign meningioma is usually equivalent to a cure.

Aggressively growing meningiomas such as atypical meningioma (WHO grade 2) or anaplastic meningioma (WHO grade 3) are rare. Overall, they make up less than 10 percent of all meningiomas. They have a higher risk of growing again after removal. In addition to surgery, adjuvant radiation therapy and, if necessary, chemotherapy or targeted medications can also be considered.

Risk factors

A known risk factor for the development of a meningioma is previous radiation therapy in the head and neck area. The tumors can appear decades after radiation treatment. Rare cancer syndromes such as neurofibromatosis type 2 (NF2) are also associated with an increased risk of meningiomas.

Female sex hormones How progesterone (progestin) and estrogen influence the growth of meningioma cells – this is indicated by both scientific data from laboratory experiments and case reports. There is clear evidence, for example, about the connection between high doses of cyproterone acetate (CPA) and the development of meningiomas. There are currently no consistent study results for other hormonal contraceptives or hormone replacement therapy.

All clear for cell phones, smartphones etc.

An increased risk of brain tumors such as meningioma through the use of mobile devices is now considered unlikely – this is also the case current data from a large international cohort study from Sweden¹.

Detection of incident meningiomas is increasing

In comparison, evaluations over the last few decades show that meningiomas are increasingly being discovered by chance.

Prevalence high: Experts suspect that asymptomatic meningiomas are very common. They estimate that 1 to 3 percent of the general population is affected².

Possible reasons: More and more (older) people are now receiving brain imaging, especially when looking for metastases due to cancer. Increasingly, powerful imaging procedures such as MRI and contrast-enhanced examinations are being carried out, with which even small meningiomas that do not cause any symptoms can be easily detected.

The dilemma: Those affected and their medical team must then decide how to deal with the incidental finding.

Observe or operate?

The data situation: To date, there are no meaningful prospective studies on the management of incident meningiomas. The available data shows that asymptomatic meningiomas that are discovered by chance and are observed usually continue to grow. However, they only very rarely lead to symptoms over time.

Estimate prognosis: Various risk scores are currently being examined internationally in order to better estimate the course of incident meningiomas in the future. An example is this IMPACT calculation tool (Incidental Meningioma: Prognostic Analysis Using Patient Comorbidity and MRI Tests). In addition to the size, growth rate and MRI changes of the tumor, patient age and comorbidities are also important parameters.

Individual consideration necessary: The approach to benign meningiomas must always weigh up the benefits of treatment for the individual against the possible limitations that the therapeutic procedure entails.

• An observation (watch and wait) is particularly an option for small meningiomas if they do not cause any symptoms and do not endanger neighboring structures.
• A surgery This should always be sought if the meningioma causes symptoms, grows rapidly in size or if there is additional imaging evidence of aggressive tumor growth.
• radiotherapy: Depending on the size and location, stereotactic radiation therapy or radiosurgery (SRS) can also be carried out as an alternative.

conclusion for practice

Once a decision has been made regarding how to proceed, questions often remain unanswered.

If observation is carried out first, the following should be considered: How frequently should checks be carried out? When is therapy necessary? How can the person affected cope with the knowledge that the tumor remains in their head?

Even after a meningioma has been removed, many questions can arise, for example about postoperative side effects, but also about driving licenses or returning to work.

Important key points when caring for people with an incidental meningioma:

• Those affected should initially see a team experienced in the treatment of brain tumors.
• Internationally, a conservative approach is preferred for small tumors in non-critical locations.
• According to experts, initial follow-up checks should be planned more closely (after 6 to 12 months). Further appointments will then be arranged individually.
• In addition to purely medical questions, psychosocial issues also play an important role in family doctor support. For the latter, cancer advice centers, for example, can also be a contact.

krebsinformationsdienst.med: Service for specialist groups