What is brain cancer?
Primary brain cancer develops from cells within the brain. Part of the central nervous system (CNS), the brain is the control center for vital functions of the body, including speech, movement, thoughts, feelings, memory, vision, hearing and more.
Primary brain tumors are classified by the type of cell or tissue the tumor affects, and the location and grade of the tumor. Tumor cells may travel short distances within the brain, but generally won't travel outside of the brain itself.
When cancer develops elsewhere in the body and spreads (metastasizes) to the brain, it’s called a secondary brain tumor, or metastatic brain cancer. Metastatic brain tumors are more common than primary brain tumors. Some cancers that commonly spread to the brain include lung, colon, kidney and breast cancers.
Brain cancer incidence
Each year, over 190,000 people in the United States are diagnosed with a primary or metastatic brain tumor (National Brain Tumor Society).
Metastatic brain tumors make up the majority, with an estimated incidence of about 10 times that of primary brain tumors. About 17,000 Americans are diagnosed with primary brain cancer each year (National Cancer Institute).
While brain tumors can develop at any age, studies show that brain cancer incidence occur most commonly in children younger than eight years old and adults over age 50.
How brain cancer develops
The brain and spinal cord together make up the central nervous system (CNS). Cancer can begin in the CNS or, more commonly, it can spread there.
Primary brain tumors are tumors that form from cells within the brain. Not all primary brain tumors are the same. Primary brain tumors can be divided into malignant or benign tumors.
- Benign primary brain tumors are not cancerous. They grow slowly, and tend to be more amendable to surgical or other treatments. However, benign brain tumors can still damage normal brain tissue and cause serious problems.
- Malignant brain tumors are more aggressive by definition. They grow more quickly and invade local structures more aggressively.
Metastatic brain tumors are tumors that spread (metastasize) to the brain from another location in the body, such as the lung, colon, breast or kidney. Metastatic brain tumors are more common than primary brain tumors.