Brain tumors are often classed as benign or malignant.
- Benign brain tumors: These brain tumors are not as aggressive as malignant tumors. The mass or growth of abnormal cells does not contain cancer cells. Benign brain tumors grow slowly and tend not spread into other tissue.
- Malignant brain tumors: This type of brain tumor does contain cancer cells and also tends not to have clear borders. These tumors are considered more dangerous as they grow rapidly and can invade other parts of the brain.
Doctors may also refer to a tumor based on where the tumor cells originated. If the tumor began in the brain, it can be referred to as a primary brain tumor. If it began in another part of the body and spread to the brain, it can be referred to as a secondary, or metastatic, brain tumor.
On May 9 2016, the World Health Organization officially reclassified all of the types of brain tumor. There are now over 120 types of brain tumors.
The American Brain Tumor Association (ABTA) estimate that there will be more than 79,000 new cases of primary brain tumors diagnosed in the United States in 2017. However, they have estimated that around one third of these will be malignant.
ABTA also estimate that there are currently around 700,000 people living with primary brain tumors in the U.S. According to ABTA, an estimated 16,700 people will die from brain and spinal cord tumors in 2017