Tumors are abnormal growths due to unnecessary cell multiplication that serves no proper function in the human body. Typically, cell multiplication is controlled by suppressor genes, which continually act to protect cells from cancer-causing genes known as oncogenes. However, when suppressor genes fail because of changes in their protein coding, tumor can develop as cell division becomes unregulated.

Whereas our body’s built-in defenses find and destroy these abnormal cells, naturally occurring chemicals sometimes hamper the ability of our immune system to see these cells, as which point they become strong enough and exist in large enough numbers to overpower any of body’s defenses.

Tumors—including those of the brain—are categorized based on whether they are malignant (also known as metastatic and cancerous) or benign (also known as primary and non-cancerous), whether they are growing quickly or slowly and whether they are localized or spreading. Classifying this way allows physicians to determine the appropriate courses of treatment for the best possible outcomes.

In the case of brain tumors, the most common symptoms are headaches, specifically upon waking up and often accompanied by nausea and vomiting; vision problems; and generalized weakness or numbness. Other symptoms dependent on the type, size and location of the tumor may be seizures, changes in mood and behavior, mental and cognitive deficiencies, fatigue, auditory problems and balance and coordination issues.

A neurological exam is the first step if the presence of a metastatic or primary brain tumor is suspected. Eye, ear, nose and muscle function will be tested, as will coordination and balance, memory and cognitive abilities. Image testing in the form of CT scans and MRIs can help determine the exact size, location and form of the tumor, and a biopsy can test whether it is benign or malignant.

For primary tumors that are localized and growing slowly, treatment will focus on relieving symptoms and monitoring the tumor to ensure is doesn’t spread and impact the brain. For metastatic tumors that are growing and spreading quickly and are or will become life threatening, surgery, radiation therapy or chemotherapy (or a combination of all) will be necessary to halt the tumor’s development or remove it from the body completely.