About brain cancer and other brain tumors

Primary brain tumors, which form from cells within the brain, may be malignant (cancerous) or benign (non-cancerous). However, even benign tumors can damage normal brain tissue and cause serious problems.

Benign tumors grow slowly and tend to be more amenable to surgical or other treatments. Malignant brain tumors are more aggressive and grow faster.

When cancer develops elsewhere in the body and spreads to the brain, it’s called a secondary brain tumor, or brain metastasis. Lung cancer, colon cancer, kidney cancer and breast cancer can all metastasize to the brain. These tumors are more common than primary brain tumors.

Brain cancer cells may travel short distances within the brain, but they generally do not spread beyond the brain. The chance of developing a malignant brain or spinal cord tumor is less than 1 percent. Men are at a slightly higher risk—about one in 140—while women have a one in 190 chance of getting this cancer type, although women are at a greater risk for certain types of brain tumors.

There is no definitive cause of brain tumors or brain cancer. The risk of developing primary brain cancer is very low. The American Cancer Society estimates the risk over a lifetime at less than 1 percent.

While risk factors for brain cancer are much less defined than for other cancers, some genetic conditions and environmental factors may contribute to the development of the disease. Those risk factors include:

• Compromised immune system
• Genetic links, such as Von Hippel-Lindau disease, Li-Fraumeni syndrome and Neurofibromatosis (NF1 and NF2), which are inherited conditions that have been found in families with a history of rare brain tumors
• Chemical exposure to certain industrial chemicals or solvents
• Previous radiation treatment

The frequency of brain cancer increases with age, with more cases in individuals aged 65 and older. The age factor varies depending on the cell type and location of the tumor.

Certain cancers, like meningiomas, are twice as likely to develop in women, while medulloblastomas—predominantly diagnosed in children—are more frequently found in males.

Although not conclusive, cancer research indicates that chemical exposure may lead to a higher incidence of some brain tumors in individuals who work in oil refining, rubber manufacturing and drug manufacturing.

There are more than 120 types of brain tumors, according to the National Brain Tumor Society. Some brain tumors, such as a glioblastoma multiforme, are malignant and may be fast-growing. Other types of brain tumors, such as meningiomas and schwannomas, may be slow-growing and benign.

The most common type of primary brain tumor is called a glioma, which originates in the glial (supportive) tissue. About one-third of all primary brain tumors and other nervous system tumors form from this type of cell.

The types of brain tumors include:

• Astrocytomas: They can form anywhere in the brain or spinal cord and are most commonly found in the cerebrum in adult brains. They include brain stem gliomas, glioblastoma multiforme and meningioma.
• Ependymomas: These cancers usually occur in the lining of the ventricles and are most common in children and adolescents.
• Oligodendroglioma: This cancer type develops in brain cells that produce myelin and is diagnosed most often in middle-aged adults. This cancer generally has more favorable outcomes than astrocytomas.
• Mixed gliomas: These have two types of tumor cells: oligodendrocytes and astrocytes.
• Pituitary adenomas: These make up the vast majority of pituitary tumors. They are benign growths that do not spread beyond the skull, but they can cause severe medical issues.
• Pituitary carcinomas: The American Cancer Society says these cancers are so rare, only a few hundred have been documented in the United States. They look similar to benign adenomas and are often diagnosed only when abnormal cells spread to other parts of the body.
• Craniopharyngiomas: These tumors develop near the pituitary gland and are usually benign. They are often considered malignant because of the damage they may do to the hypothalamus that regulates body temperature, hunger and thirst.
• Germ cell tumors: These include germinoma in the brain. They arise from developing sex cells and are most common in children.
• Pineal region tumors: These occur around the pineal gland in the center of the brain and include slow-growing pineocytoma and fast-growing pineoblastoma.
• Medulloblastomas: These cancers develop from the neurons of the cerebellum that controls movement and balance. They are fast-growing tumors usually found in children and young adults.
• Primary central nervous system (CNS) lymphomas: These tumors develop in the lymph tissue of the brain or spinal cord and are usually found in people with compromised immune systems.

Symptoms of brain cancer are influenced by which parts of the brain are involved and the functional systems affected. For example, vision problems may result from a tumor near the optic nerve. A tumor in the front part of the brain may affect the ability to concentrate and think. A tumor located in an area that controls motor function may cause weakness, numbness or difficulty with speech.

Signs of brain cancer may include:

• A headache that changes depending on the time of day and position of the head, and gets worse over time
• Seizures
• Numbness
• Nausea or vomiting
• Memory loss
• Muscle weakness
• Speech difficulty
• Mood or personality changes
• Unexplained tiredness
• Changes in menstrual cycle
• Impotence or infertility
• Overproduction or underproduction of breast milk
• Cushing’s syndrome, a condition marked by weight gain
• High blood pressure
• Diabetes
• Bruising

Some patients may experience cognitive impairments or they may have visual, speech or coordination problems. Symptoms may be subtle or develop gradually.

It’s important to understand that even noncancerous tumors often damage normal cells in the surrounding brain tissue, nerves and blood vessels. This can cause side effects, such as headaches, fatigue, double-vision or blurred vision.

Health care professionals use the following tools to diagnose brain cancer:

• Biopsy
• Laboratory tests, including advanced genomic testing that looks for DNA alterations that may be causing a cancer to grow
• Nuclear medicine bone scan
• Angiography
• Magnetic resonance imaging (MRI)
• Computed tomography scan (CT scan)
• Positron emission tomography scan (PET scan)

Treatment options for brain cancer patients include:

• Surgery, neurosurgery and craniotomy
• Minimally invasive surgical techniques, including endoscopy
• Intraoperative neuronavigation, a brain-mapping procedure
• Intraoperative electrophysiology brain-mapping, also called motor mapping and language mapping
• Intraoperative radiation therapy (IORT)
• Radiation therapy, including external beam radiation and whole-brain radiation
• Chemotherapy, including local chemotherapy (BCNU) and systemic chemotherapy
• Targeted therapy, addressing specific pathways or abnormal brain cells involved in tumor growth