A primary brain tumor is a mass created by the growth or uncontrolled proliferation of cells in the brain.

Each year, more than 17,000 people in the United States find out that they have a primary malignant brain tumor.¹ There are a few different types of brain tumors.  Astrocytomas are the most common of the primary brain tumors.  They are typically graded on a scale of I to IV, based on how quickly the cells are reproducing, as well as their ability to invade nearby tissue.²

Glioblastoma multiforme, a grade IV astrocytoma is the most common of the primary malignant brain tumors and one of the most difficult to treat effectively. Each year, approximately five out of every 100,000 people living in the United States are diagnosed with a glioblastoma. These tumors represent about 20 percent of all primary tumors found in the brain.³

Oligodendrogliomas, another type of brain tumor, represent about four percent of all primary brain tumors. About 60-65 percent of oligodendrogliomas respond to chemotherapy. New tests that are being developed may help better predict the effectiveness of chemotherapy in this group of tumors.

Risk Factors

The causes of brain tumors are not known. The more information we can learn, the better the chance of finding ways to prevent them. Doctors cannot explain why one person develops a brain tumor and another does not, but they do know that no one can “catch” a brain tumor from another person. Brain tumors are not contagious.¹  Little is known about the interaction of genetic factors and environmental toxins in the development of brain tumors.²  Because identification of the risk factors for brain tumors may aid in prevention and suggest effective treatments, high-quality epidemiological studies are extremely important.²

Signs and Symptoms

When physical signs are present, they may include a headache, weakness on one side, seizures, nausea and/or vomiting. These symptoms do not automatically indicate that a brain tumor is present.