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Brain tumor - adults
 
Alternative Names:

Glioblastoma multiforme - adults; Ependymoma - adults; Glioma - adults; Astrocytoma - adults; Medulloblastoma - adults; Neuroglioma - adults; Oligodendroglioma - adults; Meningioma - adults; Cancer - brain tumor (adults)

Definition:

A tumor is any growth of abnormal cells, or the uncontrolled growth of cells. This article is about primary brain tumors. These start in the brain, rather than spreading to the brain from another part of the body.

Causes, incidence, and risk factors:

Primary brain tumors include any tumor that starts in the brain. Tumors may be confined to a small area, invasive (spread to nearby areas), benign (not cancerous), or malignant (cancerous).

Tumors can directly destroy brain cells. They can also indirectly damage cells by producing inflammation, compressing other parts of the brain as the tumor grows, causing swelling in the brain, and increasing pressure within the skull.

Brain tumors are classified depending on the exact site of the tumor, the type of tissue involved, benign or malignant tendencies of the tumor, and other factors. Primary brain tumors can arise from the brain cells, the meninges (membranes around the brain), nerves, or glands.

The cause of primary brain tumors is unknown. This is because they are rare, there are many types, and there are many possible risk factors that could play a role. Exposure to some types of radiation, head injuries, and hormone replacement therapy may be risk factors, as well as many others. The risk of using cell phones is hotly debated.

Some inherited conditions increase the risk of brain tumors, including neurofibromatosis, Von Hippel-Lindau syndrome, Li-Fraumeni syndrome, and Turcot's syndrome.

Tumors may occur at any age, but many specific tumors have a particular age group in which they are most common. In adults, gliomas and meningiomas are most common.

SPECIFIC TUMOR TYPES

Gliomas are thought to be derived from glial cells such as astrocytes, oligodendrocytes, and ependymal cells. These tumors can have varying degrees of malignancy. The gliomas are subdivided into 3 types:
Astrocytic tumors include astrocytomas (less malignant), anaplastic astrocytomas, and glioblastomas (most malignant). Astrocytomas can progress over time more malignant forms, including glioblastoma.
Oligodendroglial tumors also can vary from low grade to very malignant. Some primary brain tumors are composed of both astrocytic and oligodendrocytic tumors. These are called mixed gliomas.
Glioblastomas are the most aggressive type of primary brain tumor. These may or may not arise from a prior lower grade primary brain tumor.
Treatment can involve surgery, radiation therapy, and chemotherapy, as well as experimental therapies in various combinations. Therefore, these tumors are best treated by a team involving a neurosurgeon, radiation oncologist, oncologist or neuro-oncologist, and others, such as neurologists and social workers.

More recently, "molecular subtyping" of tumors is being used to make decisions about how to best treat a particular tumor. Because these tumors are difficult to cure, patients should consider enrolling in a clinical trial after talking with their treatment team. All of the above tumors can be difficult to remove completely by surgery alone, because the tumor invades surrounding brain tissue much like roots from a plant. It is often difficult for a neurosurgeon to determine where the tumor ends.

Meningiomas are another type of brain tumor. These tumors:

Occur most commonly between the ages of 40 to 70
Much more common in women.
While 90% are benign, they still may cause devastating complications and death due to their size or location. Some are cancerous and aggressive.
Other primary brain tumors in adults are rare and can include ependymomas, craniopharyngiomas, pituitary tumors, pineal gland tumors, primary germ cell tumors of the brain, and other types.