Meningioma: Stages and Grades

Approved by the Cancer.Net Editorial Board, 07/2017

ON THIS PAGE: You will learn about how doctors describe meningioma and factors that help decide treatment options. This is called the stage and grade. Use the menu to see other pages.

Staging is a way of describing where the tumor is located, if it is cancerous, if or where it has spread, and whether it is affecting other parts of the body. Doctors use diagnostic tests to find out the tumor’s stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis, which is the chance of recovery. There are different stage descriptions for different types of tumors.

After meningioma has been diagnosed, additional tests will be done to learn more about the tumor. As outlined in the Risk Factors section, people with neurofibromatosis type 2 are more likely to have more than 1 meningioma. In this situation, a patient will have a variety of tests, including an MRI, to find out how much the tumor has grown within the brain and spine.

There is no formal staging system for meningioma because CNS tumors cannot be staged the same way as other types of tumors. For meningioma, doctors use the 7 factors listed below to determine the treatment options and prognosis:

  • Tumor histology and grade. How tumor tissue looks under a microscope is called tumor histology, which is performed by a pathologist. A sample of the tumor is removed during surgery for a biopsy. When surgery is not possible, a biopsy alone is done to get the sample.

    Using the histology, the pathologist can determine the type of tumor and its grade. Grade describes how likely the tumor cells are to grow quickly. The pathologist compares the tumor tissue with healthy tissue. Healthy tissue usually contains many different types of cells grouped together. If the tumor cells looks similar to healthy tissue and contain different cell groupings, it is called differentiated or a low-grade tumor. If the tumor tissue looks very different from healthy tissue, it is called poorly differentiated or a high-grade tumor. The tumor’s grade may help the doctor predict how quickly the cancer will spread. In general, the lower the tumor’s grade, the better the prognosis. To decide on a treatment, both the type and grade of the tumor must be identified.

    In general, a meningioma is classified into 1 of 3 grades:

    • A grade I tumor grows slowly.
    • A grade II tumor grows more quickly and is often called atypical meningioma.

    • A grade III tumor grows and spread very quickly and is often called anaplastic or malignant meningioma.

  • Labeling Index using MIB-1 test. This test identifies cells that are actively dividing, which can be linked with the aggressiveness of the tumor. The more cells that are dividing, the more likely it is that the tumor will grow quickly. Generally, a slow-growing meningioma has a MIB-1 of less than 5%.

  • Age of patient. In adults, the age that a person is diagnosed with meningioma is one of the best ways to predict prognosis. In general, the younger the adult, the better the prognosis.

  • Extent of tumor residual. This is how much of the tumor was left behind after surgery. It includes 3 classifications:

    • Gross total. The entire tumor was removed, although microscopic cells may remain.

    • Subtotal. Only part of the tumor was removed.

    • Biopsy only. Only a small portion, used for a biopsy, was removed.

The prognosis is better when all of the tumor can be surgically removed.

  • Tumor location. Tumors can form in any part of the CNS. A tumor can cause more damage to some areas than others. Some tumors are harder to completely remove than others because of where they are located.

  • Functional neurologic status. The doctor will test how well a patient’s CNS is working by using an assessment called the Karnofsky Performance Scale. A higher score indicates a better prognosis.

  • Metastatic spread. Meningioma very rarely spreads to other parts of the body.

Recurrent meningioma

A recurrent tumor is one that has come back after treatment. If the tumor does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.

Biogenetic markers

The factors listed above are the best ways to determine the prognosis for a person with meningioma. Researchers are currently looking for tumor markers that could make meningioma easier to diagnose and allow the staging of adult CNS tumors. These tools may someday make it possible for doctors to determine how quickly a brain tumor will grow and spread, develop more effective treatments, and more accurately predict prognosis.

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition published by Springer-Verlag New York, www.cancerstaging. org.

Information about the tumor will help the doctor recommend a specific treatment plan. The next section in this guide is Treatment Options. You may use the menu to choose a different section to read in this guide.