About brain cancer
What is brain cancer?
What is brain cancer?
Brain cancer is a disease of the brain in which cancer cells (malignant cells) arise in the brain tissue. Cancer cells grow to form a mass of cancer tissue (tumor) that interferes with brain functions such as muscle control, sensation, memory, and other normal body functions. Tumors composed of cancer cells are called malignant tumors, and those composed of mainly noncancerous cells are called benign tumors. Cancer cells that develop from brain tissue are called primary brain tumors while tumors that spread from other body sites to the brain are termed metastatic or secondary brain tumors. Statistics suggest that brain cancer occurs infrequently and is likely to develop in about 22,850 new people per year with about 15,320 deaths as estimated by the National Cancer Institute (NCI) and the American Cancer Society.
What are grades of brain cancers?
Not all brain tumors are alike, even if they arise from the same type of brain tissue. Tumors are assigned a grade depending on how the cells in the tumor appear microscopically. The grade also provides insight as to the cell's growth rate. NCI lists the following grades from benign to most aggressive (grade IV):
- Grade I: The tissue is benign. The cells look nearly like normal brain cells, and they grow slowly.
- Grade II: The tissue is malignant. The cells look less like normal cells than do the cells in a grade I tumor.
- Grade III: The malignant tissue has cells that look very different from normal cells. The abnormal cells are actively growing and have a distinctly abnormal appearance (anaplastic).
- Grade IV: The malignant tissue has cells that look most abnormal and tend to grow quickly.
What are the types of brain cancers?
The most common primary brain tumors are usually named for the brain tissue type (including brain stem cancers) from which they originally developed. These are gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, and primitive neuroectodermal tumors (medulloblastomas). Gliomas have several subtypes, which include astrocytomas, oligodendrogliomas, ependymomas, and choroid plexus papillomas. These names all reflect different types of cells in the normal brain that can become cancers. When the grades are coupled with the tumor name, it gives doctors a better understanding about the severity of the brain cancer. For example, a grade III (anaplastic) glioma is an aggressive tumor, while an acoustic neuroma is a grade I benign tumor. However, even benign tumors can cause serious problems if they grow big enough to cause increased intracranial pressure or obstruct vascular structures or cerebrospinal fluid flow.
What is brain cancer staging?
Brain cancers are staged (stage describes the extent of the cancer) according to their cell type and grade because they seldom spread to other organs, while other cancers, such as breast or lung cancer, are staged according to so-called TMN staging which is based on the location and spread of cancer cells. In general, these cancer stages range from 0 to 4; with stage 4 indicating the cancer has spread to another organ (highest stage is 4).
What is metastatic brain cancer?
Cancer cells that develop in a body organ such as the lung (primary cancer tissue type) can spread via direct extension, or through the lymphatic system and/or through the bloodstream to other body organs such as the brain. Tumors formed by such cancer cells that spread (metastasize) to other organs are called metastatic tumors. Metastatic brain cancer is a mass of cells (tumor) that originated in another body organ and has spread into the brain tissue. Metastatic tumors in the brain are more common than primary brain tumors. They are usually named after the tissue or organ where the cancer first developed (for example, metastatic lung or breast cancer tumors in the brain, which are the most common types found). Occasionally, an abbreviated name may be used that often confuses people; for example, "small cell brain cancer" actually means "small cell lung cancer that has metastasized to the brain." People should not hesitate to ask their doctor about any terms they do not understand or about the origin of their cancer.
What are the symptoms for brain cancer?
General signs and symptoms caused by brain tumors may include:
- New onset or change in pattern of headaches
- Headaches that gradually become more frequent and more severe
- Unexplained Nausea or vomiting
- Vision problems, such as blurred vision, double vision or loss of peripheral vision
- Gradual Loss of sensation or movement in an arm or a leg
- Difficulty with balance
- Speech difficulties
- Feeling very tired
- Confusion in everyday matters
- Difficulty making decisions
- Inability to follow simple commands
- Personality or behavior changes
- Seizures, especially in someone who doesn't have a history of seizures
- Hearing problems
What are the causes for brain cancer?
Brain tumors that begin in the brain Acoustic neuroma (schwannoma) Open pop-up dialog box Close Acoustic neuroma (schwannoma) Acoustic neuroma (schwannoma)
An acoustic neuroma (schwannoma) is a benign tumor that develops on the balance and hearing nerves leading from your inner ear to the brain. These nerves are twined together to form the vestibulocochlear nerve (eighth cranial nerve). The pressure on the nerve from the tumor may cause hearing loss and imbalance.Medulloblastoma Open pop-up dialog box Close Medulloblastoma Medulloblastoma
Medulloblastoma is a type of brain cancer that starts in the part of the brain called the cerebellum. Medulloblastoma is the most common type of cancerous brain tumor in children.
Primary brain tumors originate in the brain itself or in tissues close to it, such as in the brain-covering membranes (meninges), cranial nerves, pituitary gland or pineal gland.
Primary brain tumors begin when normal cells develop changes (mutations) in their DNA. A cell's DNA contains the instructions that tell a cell what to do. The mutations tell the cells to grow and divide rapidly and to continue living when healthy cells would die. The result is a mass of abnormal cells, which forms a tumor.
In adults, primary brain tumors are much less common than are secondary brain tumors, in which cancer begins elsewhere and spreads to the brain.
Many different types of primary brain tumors exist. Each gets its name from the type of cells involved. Examples include:
- Gliomas. These tumors begin in the brain or spinal cord and include astrocytomas, ependymomas, glioblastomas, oligoastrocytomas and oligodendrogliomas.
- Meningiomas. A meningioma is a tumor that arises from the membranes that surround your brain and spinal cord (meninges). Most meningiomas are noncancerous.
- Acoustic neuromas (schwannomas). These are benign tumors that develop on the nerves that control balance and hearing leading from your inner ear to your brain.
- Pituitary adenomas. These are tumors that develop in the pituitary gland at the base of the brain. These tumors can affect the pituitary hormones with effects throughout the body.
- Medulloblastomas. These cancerous brain tumors are most common in children, though they can occur at any age. A medulloblastoma starts in the lower back part of the brain and tends to spread through the spinal fluid.
- Germ cell tumors. Germ cell tumors may develop during childhood where the testicles or ovaries will form. But sometimes germ cell tumors affect other parts of the body, such as the brain.
- Craniopharyngiomas. These rare tumors start near the brain's pituitary gland, which secretes hormones that control many body functions. As the craniopharyngioma slowly grows, it can affect the pituitary gland and other structures near the brain.
Secondary (metastatic) brain tumors are tumors that result from cancer that starts elsewhere in your body and then spreads (metastasizes) to your brain.
Secondary brain tumors most often occur in people who have a history of cancer. Rarely, a metastatic brain tumor may be the first sign of cancer that began elsewhere in your body.
In adults, secondary brain tumors are far more common than are primary brain tumors.
Any cancer can spread to the brain, but common types include:
- Breast cancer
- Colon cancer
- Kidney cancer
- Lung cancer
What are the treatments for brain cancer?
A treatment plan is individualized for each brain cancer patient. The treatment plan is constructed by the doctors who specialize in brain cancer, and treatments vary widely depending on the cancer type, brain location, tumor size, patient age, and the patient's general health status. A major part of the plan is also determined by the patient's wishes. Patients should discuss treatment options with their health-care providers.
Surgery, radiation therapy, and chemotherapy are the major treatment categories for most brain cancers. Individual treatment plans often include a combination of these treatments. Surgical therapy attempts to remove all of the tumor cells by cutting the tumor away from normal brain tissue. This surgery is often termed invasive surgery to distinguish it from noninvasive radiosurgery or radiation therapy described below. Some brain cancers are termed inoperable by surgeons because attempting to remove the cancer may cause further brain damage or death. However, a brain cancer termed inoperable by one surgeon may be considered operable by another surgeon. Patients with a diagnosis of an inoperable brain tumor should consider seeking a second opinion before surgical treatment is abandoned.
Radiation therapy attempts to destroy tumor cells by using high-energy radiation focused onto the tumor to destroy the tumor cells' ability to function and replicate. Radiosurgery is a nonsurgical procedure that delivers a single high dose of precisely targeted radiation using highly focused gamma-ray or X-ray beams that converge on the specific area or areas of the brain where the tumor or other abnormality is located, minimizing the amount of radiation to healthy brain tissue. Equipment used to do radiosurgery varies in its radiation source; a gamma knife uses focused gamma rays, and a linear accelerator uses photons, while heavy-charged particle radiosurgery uses a proton beam.
Chemotherapy attempts to destroy tumor cells using chemicals (drugs) that are designed to destroy specific types of cancer cells. There are many chemical agents used; specific drug therapies are numerous, and each regimen is usually designed for the specific type of brain cancer and individualized for each patient. For example, bevacizumab (Avastin) is a drug approved for treatment of glioblastomas (glioblastoma multiforme). Chemotherapy can be administered intrathecally (into the cerebrospinal fluid by a spinal tap or through a surgically placed permanent reservoir under the scalp attached through a sterile tubing placed into the fluid-containing chambers in the brain), by IV administration, and biodegradable chemically impregnated polymers. All treatments attempt to spare normal brain cells.
Other treatment options may include hyperthermia (heat treatments), immunotherapy (immune cells directed to kill certain cancer cell types), or steroids to reduce inflammation and brain swelling. These may be added on to other treatment plans.
Clinical trials (treatment plans designed by scientists and physicians to try new chemicals or treatment methods on patients) can be another way for patients to obtain treatment specifically for their cancer cell type. Clinical trials are part of the research efforts to produce better treatments for all disease types. Stem cell treatments for brain and brain stem cancers and other conditions may be available, because research with patients is ongoing using these potential therapies. The best treatment for brain cancer is designed by the team of cancer specialists in conjunction with the wishes of the patient.
What are the risk factors for brain cancer?
In most people with primary brain tumors, the cause of the tumor isn't clear. But doctors have identified some factors that may increase your risk of a brain tumor.
Risk factors include:
- Exposure to radiation. People who have been exposed to a type of radiation called ionizing radiation have an increased risk of brain tumor. Examples of ionizing radiation include radiation therapy used to treat cancer and radiation exposure caused by atomic bombs.
- Family history of brain tumors. A small portion of brain tumors occurs in people with a family history of brain tumors or a family history of genetic syndromes that increase the risk of brain tumors.