Brain Cancer

There are two types of brain tumors: primary brain tumors that originate in the brain and metastatic (secondary) brain tumors that originate from cancer cells that have migrated from other parts of the body.

Primary brain cancer rarely spreads beyond the central nervous system, and death results from uncontrolled tumor growth within the limited space of the skull. Metastatic brain cancer indicates advanced disease and has a poor prognosis.

Brain Cancer Picture

Primary brain tumors can be cancerous or noncancerous. Both types take up space in the brain and may cause serious symptoms (e.g., vision or hearing loss) and complications (e.g., stroke).

All cancerous brain tumors are life threatening (malignant) because they have an aggressive and invasive nature. A noncancerous primary brain tumor is life threatening when it compromises vital structures (e.g., an artery).

Aside from a known association with exposure to vinyl chloride, there are no known chemical or environmental agents that lead to the development of brain tumors.

Genetic mutations and deletions of tumor suppressor genes (i.e., genes that suppress the development of malignant cells) increase the risk for some types of brain cancer. Inherited diseases that are associated with brain tumors include the following:

• Multiple endocrine neoplasia type 1 (pituitary adenoma)
• Neurofibromatosis type 2 (brain and spinal cord tumors)
• Retinoblastoma (malignant retinal glioma)
• Tuberous sclerosis (primary brain tumors)
• Von Hippel-Lindau disease (retinal tumor, CNS tumors)

Patients with a history of melanoma, lung, breast, colon, or kidney cancer are at risk for secondary brain cancer.

Exposure to vinyl chloride is an environmental risk factor for brain cancer. Vinyl chloride is a carcinogen, that is, a cancer-causing substance. It is used in manufacturing plastic products such as pipes, wire coatings, furniture, car parts, and housewares, and is present in tobacco smoke.

Manufacturing and chemical plants may release vinyl chloride into the air or water, and it may leak into the environment as a result of improper disposal. People who work in these plants or live in close proximity to them have an increased risk for brain cancer.

A brain tumor can obstruct the flow of cerebrosinal fluid (CSF), which results in the accumulation of CSF (hydrocephalus) and increased intracranial pressure (IICP). Nausea, vomiting, and headaches are common symptoms.

Brain tumors can damage vital neurological pathways and invade and compress brain tissue. Symptoms usually develop over time and their characteristics depend on the location and size of the tumor. A brain tumor in the frontal lobe may cause the following:

• Behavioral and emotional changes
• Impaired judgment
• Impaired sense of smell
• Memory loss
• Paralysis on one side of the body (hemiplegia)
• Reduced mental capacity (cognitive function)
• Vision loss and inflammation of the optic nerve (papilledema)

A tumor located in both the right and left hemispheres of the frontal lobe often cause behavioral changes, cognitive changes, and a clumsy, uncoordinated gait.

A tumor in the parietal lobe may cause the following symptoms:

• Impaired speech
• Inability to write
• Lack of recognition
• Seizures
• Spatial disorders

Vision loss in one or both eyes and seizures may result from a tumor located in the occipital lobe.

Tumors that develop in the temporal lobe are often asymptomatic (i.e., without symptoms), but some may cause impaired speech and seizures.

A tumor in the brainstem may produce the following symptoms:

• Behavioral and emotional changes (e.g., irritability)
• Difficulty speaking and swallowing
• Drowsiness
• Headache, especially in the morning
• Hearing loss
• Muscle weakness on one side of the face (e.g., head tilt, crooked smile)
• Muscle weakness on one side of the body (i.e., hemiparesis)
• Uncoordinated gait
• Vision loss, drooping eyelid (i.e., ptosis) or crossed eyes (i.e., strabismus)
• Vomiting

Ependymoma originates in the lining of the ventricles and the spinal canal and may damage cranial nerves. When this happens, hydrocephalus, stiff neck, head tilt, and weakness may result.

Symptoms produced by a tumor of the meninges (meningioma) depend on which area of the brain is being compressed. They include:

• Headache
• Hearing loss
• Impaired speech (i.e., dysphasia)
• Incontinence
• Mental and emotional changes (e.g., indifference, disinhibition)
• Prolonged drowsiness (somnolence)
• Seizures
• Vision loss

A tumor located in the pituitary gland (i.e., pituitary adenoma) may increase the secretion of hormones and cause discontinuation of menstruation (i.e., amenorrhea) and excess secretion of milk (i.e., galactorrhea) in women. Impotence may occur in men.

Metastatic brain cancer tends to invade the brain tissue indiscriminately. Some symptoms include the following:

• Bleeding
• Headache
• Impaired mental function
• Motor dysfunction
• Nausea
• Seizures
• Swelling
• Vomiting

Complications Drastic and sometimes life-threatening complications can develop with brain cancer.
Obstructed flow of cerebrospinal fluid from the third ventricle may cause sudden death.
Cerebral hernia is a progressive, fatal condition in which the brain is forced through an opening in the skull.
Hemorrhagic stroke produces sudden loss of vision and/or speech, unconsciousness, and paralysis.