Observation of Meningiomas: When Is It Time to Watch and Wait?

A brain tumor is a serious diagnosis and can be devastating news for you and your family. The most common primary brain tumor is a meningioma, a tumor that originates from the layers of the meninges that surrounds the brain and spinal cord. But there’s good news. Meningiomas are often benign and if the tumor is small and not causing you any problems, it may not need to be actively treated.

If you have been diagnosed with a meningioma, you will want to learn more about the role of observation as a viable management plan.

Depending upon the size and location of a meningioma, symptoms will vary. Most of these slow-growing, benign tumors may not cause any symptoms for months or even years. Larger tumors or tumors near critical structures may cause symptoms due to the pressure they are placing on the brain or surrounding nerves.

Symptoms may include seizures, nausea, vomiting, headache, dizziness, imbalance or difficulty walking, memory problems, cognitive difficulty, and language impairment.

Surgery is the most common treatment for meningiomas. Sometimes radiation therapy is used to help stop the growth of the remaining tumor after surgery or when surgery is not feasible. In the case of slow-growing, benign meningiomas with few or no symptoms, your doctor may opt for observation, or "watch and wait." 

About 80% of meningiomas are benign, meaning that they are not made up of cancerous or malignant cells that change or grow rapidly and move quickly to spread to other areas of the body.

Benign meningiomas may still cause a serious problem, however, depending upon their size and location. They may continue to grow over time, putting pressure on specific parts of the brain and causing symptoms which can be very severe and lead to a poor prognosis if left untreated. However, there are certain times when your doctor will recommend observation as the best management plan:

Most patients suffering from a meningioma have tumors that are small, benign, and slow-growing. As a result, the patient may not have any symptoms at the time the tumor is diagnosed, or symptoms may be very mild. In such cases, the doctor may choose to observe the patient and monitor the tumor for changes on a regular basis.

The frequency of monitoring with MRIs will be about every 6-12 months and anytime new symptoms occur.

Meningiomas that are located near the brainstem or close to major blood vessels are difficult to access/remove and pose safety risks during an operation. If the risks of making you worse with active treatment outweigh the potential benefits, your doctor may recommend observation instead.  

Because meningiomas are more common in patients over 65, some patients with meningioma are frail or suffer from poor health. If it is difficult for a particularly ill or elderly patient to endure more aggressive treatments such as surgery, in such cases, the doctor may opt for watching and waiting.              

Besides age, there are other risk factors that may make a person more likely to develop a meningioma. Benign meningiomas affect about twice as many women than men. Also, meningiomas are more likely to occur in Blacks than Whites and in individuals with specific genetic disorders (e.g., Neurofibromatosis 2). Finally, individuals who have been exposed to excessive radiation are at a greater risk of developing meningiomas. 

Depending upon the risk factors listed above and a patient's personal medical history, there are benefits and risks associated with undergoing observation as a management plan for your meningioma instead of more aggressive treatment.

Avoid potential risks of active treatments

Undergoing an observational approach means avoiding risks that come with other treatment options. Although modern surgery and radiation therapies are much safer today than they were in the early years of medicine, there is still potential for, albeit small, serious side effects such as stroke and impaired brain function.

Maximizing quality of life

Although surgery and radiation therapy are relatively routine procedures in medicine, this can be a big commitment for the patient. Organizing transportation to and from the hospital, figuring out where to stay during recovery and what it might mean for your job and finances are just a few of the many items that will require planning. For some patients with little to no symptoms, pursuing active treatment is not worth it at this time but may be considered at a future date.   

Patients with aggressive tumors who underwent multiple surgeries or radiation treatments may decide to stop actively treating the tumor if the side effects of treatments are making it difficult to enjoy their life. Older patients may also feel that active treatment is not necessary if the tumor is growing too slowly to cause a problem in their lifetime. When discussing treatment options with your surgeon, it is important to discuss your thoughts about what matters most to you so the final decision is consistent with your priorities and goals.

Additional emotional impact

While a patient may avoid aggressive treatment and potential side effects by undergoing a period of observation, the "watch and wait" approach can be emotionally taxing on the patient and their family members.

It can be upsetting and frightening to undergo months or years of observation without pursuing active treatment until the tumor becomes larger.

Stressful follow-up appointments

Even benign meningiomas may progress over time. Patients with follow-up appointments frequently experience stress and anxiety as they wait to find out if their latest imaging results revealed any signs of progression. 

Risk of tumor growth

During the “watch-and-wait” period, there is a small chance that the tumor will grow more than expected by the time the patient has their next follow-up MRI. In very rare cases, a benign Grade I tumor may progress to a higher-grade tumor where abnormal and/or malignant cells are detected by the time the surgery is performed.

By watching and waiting until these changes occur, doctors and patients may wait too long and future treatment attempts may be less effective. 

There are different subtypes of meningiomas depending upon their location and characteristics observed under the microscope. According to the World Health Organization's (WHO) classification of meningiomas, benign and slow-growing meningiomas that very slowly grow receive a grade of I.

If you have been diagnosed with one of these slow-growing meningiomas and have a small non-symptomatic tumor, or if you are not a good candidate for surgery, your doctor may choose to select formal observation or monitoring as a management plan for your meningioma:

• Meningothelial
• Fibrous (fibroblastic)
• Transitional
• Psammomatous
• Angiomatous
• Microcystic
• Secretory
• Lymphoplasmacyte-rich
• Metaplastic

Grade II and III meningiomas based on WHO classification are more aggressive and observation is not recommended. However, it is difficult to assess the grade of the tumor without surgery and based on MRI alone. Therefore, serial MRI imaging is important to diagnose faster growing tumors before surgery. 

While your doctor formally monitors or observes your meningioma, you may also receive recommendations for other types of non-surgical treatment. These include:

Medications are usually reserved for patients who have cancerous meningiomas or meningiomas that repeatedly come back. Interferon, bevacizumab, and hydroxyurea are several medications that may be used to treat meningiomas for patients that may not be able to receive surgery or have abnormal or cancerous tumors. Medications that keep the hormone progesterone from attaching to meningioma cells may be used.

Unfortunately, none of the above medicines has proven to be effective in affecting meningioma growth and all are considered experimental.

There is not any definitive research about the impact of diet on meningioma growth. So far, experts have not conclusively found any diet that works without surgery, radiation, or radiosurgery to make a tumor shrink or disappear. 

While a slow-growing tumor such as a meningioma may still grow or recur after surgical removal, the prognosis or outlook for grade I meningioma tumors is generally good and observation is frequently used to monitor non-symptomatic tumors over time. If you or someone you know has a Grade I meningioma, or if you are not a good candidate for other treatment options like surgery, ask your doctor about observation as a management plan.

• American Association of Neurological Surgeons 
• National Cancer Institute 
• American Brain Tumor Society 
• National Brain Tumor Society