Understand Primary Brain Tumors – Brain Science Foundation
Doctors have three basic treatment options for brain tumors: surgery, radiation therapy, and chemotherapy. Progress is also being made with biological treatment.
The “wait-and-monitor” option, also know as conservative management, may be a reasonable choice for a patient with a small and asymptomatic meningioma. An asymptomatic tumor would have been discovered on neuroimaging (e.g., CT or MRI) of the patient’s brain for other health concerns. If conservative management is chosen, the patient would continue to have neuroimaging scans on a regular basis to follow the behavior of the tumor. If the tumor is not growing and the patient remains asymptomatic, then the tumor may continue to be monitored. It is not uncommon for some patients to live out their lives without requiring any treatment. It should be noted that in some cases, the conservative management option may be chosen even though a tumor is causing symptoms (for example, seizures), if the symptoms can be treated successfully with medication and/or there are other reasons for wanting to avoid surgery.
In most cases, if a tumor is causing symptoms, surgery would be the first treatment choice, barring other complications. Complete removal of the tumor is the goal, as this allows the best chance for the least likelihood of tumor recurrence, increased patient survival time, and the potential easing or complete disappearance of symptoms. In one study, it was shown that complete surgical removal of the tumor was accomplished in 80% of the patients and that in these cases, there was no tumor recurrence in 88% of them at five years (progression-free survival) and in 75% of them at 10 years.
As pointed out previously, complete removal of the tumor is not always possible due to such factors as its location and size. In this case, there is greater likelihood of tumor recurrence and a decrease in patient survival times, even if the tumor is benign. The study mentioned above, found that in those with incomplete tumor removal, progression-free survival was 61% at five years and 39% at 10 years. As for patients with atypical and malignant tumors, the degree of tumor removal is also influential, but the tumor grade is the most significant factor influencing recurrence and patient lifespan. See the section on Types of Meningiomas dscription of the WHO tumor grades.)
In cases where there is tumor recurrence, treatment options may include surgery and/or radiation therapy (discussed below) with all factors taken into consideration, including previous treatment used to treat the tumor, degree of tumor removal, and grade of the tumor.
Prior to surgery, neuroimaging (primarily MRI) of the tumor is performed to help in the planning of the surgical approach to be taken and can also be used during surgery providing 3-dimensional guided imagery. While the location of the tumor will influence the particular surgical approach chosen, most often a neurosurgeon will remove a piece of skull bone to gain access to the brain. This operation is called a craniotomy. After surgery, the bone is usually put back in place and secured with small plates and screws. Sometimes due to complications, the bone cannot be replaced, or replaced immediately, in which case other materials are used to cover the hole in the skull and protect the brain.
The major goal of radiation treatment is to kill meningioma tumor cells while minimizing damage to surrounding normal brain tissue. Radiation therapy for meningiomas involves externally beaming from a machine high energy X-rays at the tumor site (known as external beam radiation). There are variations of radiation therapy and the type chosen is based on factors used for determining treatment options discussed at the beginning of this section (size, location, symptoms, age and health of patient), as well as the extent of tumor removal and the WHO grade of the meningioma.
Radiation therapy is often prescribed following surgery where there has been incomplete tumor removal, regardless of the tumor grade. When used as such, the treatment is called adjuvant radiotherapy, meaning it is used in addition to the primary treatment option of surgery in order to increase the chances of a more positive outcome. In the case of benign meningiomas that were incompletely removed, its use has been effective in decreasing the recurrence rates.
If there has been complete tumor resection, radiation is not recommended for benign tumors. In some cases, however, radiation may be recommended as follow-up treatment with atypical and malignant tumors despite complete removal. While some studies have indicated that this type of follow-up radiation therapy does have a positive effect in reducing atypical and malignant meningioma recurrence rates, more rigorous research is needed to obtain a more accurate assessment of its efficacy under these circumstances.
With recurrent tumors, some form of radiation therapy and/or surgery may be recommended.
The most common adjuvant radiation is conventional external beam radiation, which typically involves treatment given five days a week for 5 to 7 weeks. Intensity-modulated radiation therapy (IMRT) is a specialized variation of this type and allows the radiation to conform more closely to the shape of the tumor and allows greater control of the amount of radiation being received by the tumor cells versus the surrounding healthy tissue. A linear accelerator (LINAC) is used to beam the radiation.
Radiation therapy is also used as a treatment option when tumors are inoperable, in locations where the risk of surgery is considered too high, or the patient is not a good surgical risk. Two variations of external beam radiation often employed in these cases are stereotactic radiosurgery and stereotactic radiotherapy. Stereotactic radiosurgery is not actually surgery, but rather a delivery of a very intense dose of radiation, much higher than the daily dose received with conventional radiation. It is given in a single dose that is delivered by either a Gamma Knife machine or a linear accelerator. This radiation methodology is only appropriate for small tumors. Stereotactic radiotherapy is similar to stereotactic radiosurgery, except that instead of one high dose of radiation, the dose is broken down into smaller amounts of radiation and administered over several sessions to achieve the desired total dose of radiation (also known as fractionated stereotactic radiotherapy). This can help reduce damage to healthy brain tissue, while still allowing the appropriate radiation dose to reach the tumor.
More recently, stereotactic radiosurgery has been employed as the first treatment option to destroy smaller meningiomas, even though surgery was possible. While some studies have indicated that this approach may be just as effective as surgery as a primary treatment, there is not yet a consensus regarding this approach, and surgery, if possible, is still the preferred initial treatment option (unless the wait-and-monitor approach is a reasonable alternative).
Biological therapies are therapies that enhance or improve the body’s natural ability to fight disease, or are based on the normal mechanisms utilized to control growth. One example of a type of biological therapy is “immunotherapy,” which uses the body’s immune system to control or destroy tumor cells. Biological therapies are sometimes referred to as “biological response modifiers” because they are intended to optimize or somehow change the body’s response to growing tumor cells.