Types of Cancer : Brain tumor

Definition

A brain tumor is a mass or growth of abnormal cells in your brain. Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant). Brain tumors can begin in your brain (primary brain tumors), or cancer can begin in other parts of your body and spread to your brain (secondary, or metastatic brain tumors).

The number of brain tumors diagnosed each year is increasing. There's evidence the increase has been occurring for decades. But it's not clear why.

Symptoms

The signs and symptoms of a brain tumor vary greatly and depend on the brain tumor's size, location and rate of growth.

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
• Confusion in everyday matters
• Personality or behavior changes
• Seizures, especially in someone who doesn't have a history of seizures
• Hearing problems
• Hormonal (endocrine) disorders

Causes

Brain tumors that begin in the brain
Primary brain tumors originate in the brain or 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 acquire errors (mutations) in their DNA. These mutations allow cells to grow and divide at increased rates and to continue living when healthy cells would die. The result is a mass of abnormal cells, which forms a tumor.

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:

• Acoustic neuroma (schwannoma)
• Astrocytoma, also known as glioma, which includes anaplastic astrocytoma and glioblastoma
• Ependymoma
• Ependymoblastoma
• Medulloblastoma
• Meningioma
• Neuroblastoma
• Oligodendroglioma
• Pineoblastoma

Cancer that begins elsewhere and spreads to 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. In some cases you may have a history of cancer when a brain tumor is discovered. In other cases, a brain tumor is the first sign of cancer that began elsewhere in your body.

Secondary brain tumors are far more common than are primary brain tumors. Any cancer can spread to the brain, but the most common ones include:

• Breast cancer
• Colon cancer
• Kidney cancer
• Lung cancer
• Melanoma
• Neuroblastoma
• Sarcoma

Risk factors

Though doctors aren't sure what causes the genetic mutations that can lead to primary brain tumors, they've identified factors that may increase your risk of a brain tumor. Risk factors include:

• Your race. Brain tumors occur more frequently in whites than they do in others. One exception is meningioma, which occurs most frequently in blacks.
• Your age. Your risk of a brain tumor increases as you age. The majority of brain tumors occur in people 45 and older. However, a brain tumor can occur at any age. And certain types of brain tumors, such as medulloblastomas, occur almost exclusively in children.
• 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. More-common forms of radiation, such as electromagnetic fields from power lines and radiofrequency radiation from cell phones and microwave ovens, have not been conclusively linked to brain tumors.
• Chemical exposure on the job. People working in certain industries have an increased risk of brain tumors, possibly because of the chemicals they're exposed to on the job. Studies don't always agree, but there is some evidence of an increased risk of brain tumor in certain industries, including agricultural, electrical, health care and oil refineries.
• Family history of brain tumors. A small portion of brain tumors occur in people with a family history of brain tumors or a family history of genetic syndromes that increase the risk of brain tumors.

When to seek medical advice

Make an appointment with your doctor if you have signs and symptoms that concern you. These may include headaches that progressively worsen, are particularly severe, are always in the same location or are accompanied by nausea or vomiting or by blurred or double vision.

Tests and diagnosis

If it's suspected that you have a brain tumor, your doctor may recommend a number of tests and procedures, including:

• A neurological exam. A neurological exam may include, among other things, checking your vision, hearing, balance, coordination and reflexes. Difficulty in one or more areas may provide clues about the part of your brain that could be affected by a brain tumor.
• Imaging tests. Magnetic resonance imaging (MRI) is commonly used to help diagnose brain tumors. MRI uses magnetic fields and radio waves to generate images of the brain. In some cases a dye may be injected through a vein in your arm before your MRI. A number of specialized MRI scans may help your doctor in evaluation and treatment planning, including functional MRI, perfusion MRI and magnetic resonance spectroscopy.
• Tests to find cancer in other parts of your body. If it's suspected that your brain tumor may be a result of cancer that has spread from another area of your body, your doctor may recommend tests and procedures to determine where the cancer originated. One example might be a chest X-ray to look for signs of lung cancer.

• Collecting and testing a sample of abnormal tissue (biopsy). A biopsy can be performed as part of an operation to remove the brain tumor, or a biopsy can be performed using a needle. A stereotactic needle biopsy may be done for brain tumors in hard to reach areas or very sensitive areas within your brain that might be damaged by a more extensive operation. Your neurosurgeon drills a small hole, called a burr hole, into your skull. A narrow, thin needle is then inserted through the hole. Tissue is removed using the needle, which is frequently guided by computerized tomography (CT) or MRI scanning.

  The biopsy sample is then viewed under a microscope to determine if it is cancerous or benign. This information is helpful in guiding treatment.

Complications

A brain tumor can cause complications depending on the part of your brain that's affected. Complications can include:

• Weakness. A brain tumor can damage any part of the brain. But if the part of the brain involved happens to control strength or movement of an arm or leg, it could produce definite weakness in that part of the body. Weakness caused by a brain tumor can be very similar to that caused by a stroke.
• Vision changes. A brain tumor that damages the nerves that connect to the eyes or the part of the brain that processes visual information (visual cortex) can lead to vision problems, such as double vision or a reduced field of vision.
• Headaches. A brain tumor that causes increased pressure within the brain can cause headaches. These headaches can be severe and unrelenting and may be accompanied by nausea and vomiting. Headaches can be due to the tumor itself, or they can result from fluid building up in the brain (hydrocephalus).
• Personality changes. Tumors in certain areas of the brain may cause personality changes or changes in behavior.
• Hearing loss. Brain tumors that affect the auditory nerves — especially acoustic neuromas — may cause hearing loss in the ear on the involved side of the brain.
• Seizures. A brain tumor can cause irritation to the brain that can result in a seizure.

Treatments and drugs

Treatment for a brain tumor depends on the type, size and location of the tumor, as well as your overall health and your preferences. Your doctor can tailor treatment to fit your particular situation.

Surgery
If the brain tumor is located in a place that makes it accessible for an operation, your surgeon will work to remove as much of your brain tumor as possible. In some cases, tumors are small and easy to separate from surrounding brain tissue, which makes complete surgical removal possible. In other cases, tumors are located near sensitive areas in your brain, making surgery risky. In these situations your doctor may try to remove as much of the tumor as is safe. Even removing a portion of the brain tumor may help reduce signs and symptoms you experience. In some cases only a small biopsy is taken to confirm the diagnosis.

Surgery to remove a brain tumor carries risks, such as infection and bleeding. Other risks may depend on the part of your brain where your tumor is located. For instance, surgery on a tumor near nerves that connect to your eyes may carry a risk of vision loss.

Radiation therapy
Radiation therapy uses beams of high-energy particles, such as X-rays, to kill tumor cells. Radiation therapy can come from a machine outside your body (external beam radiation), or, in very rare cases, radiation can be placed inside your body close to your brain tumor (brachytherapy).

External beam radiation can focus just on the area of your brain where the tumor is located, or it can be applied to your entire brain (whole brain radiation). Whole brain radiation is sometimes used after surgery to kill tumor cells that might have been left behind. Whole brain radiation may also be an option if you have several brain tumors that can't be removed through surgery. Whole brain radiation is often used in situations where cancer has metastasized to the brain.

Side effects of radiation therapy will depend on the type and dose of radiation you receive. In general it can cause fatigue, headaches and scalp irritation.

Radiosurgery
Stereotactic radiosurgery is not a form of surgery in the traditional sense. Instead, radiosurgery uses multiple beams of radiation to give a highly focused form of radiation treatment to kill the tumor cells in a very small area. Each beam of radiation isn't particularly powerful, but the point where all the beams meet — at the brain tumor — receives a very large dose of radiation to kill the tumor cells.

Radiosurgery may be an option if your brain tumor can't be removed with traditional surgery. Radiosurgery is typically done in one treatment, and in most cases you can go home the same day. Side effects may include fatigue, headache and nausea.

Chemotherapy
Chemotherapy uses drugs to kill tumor cells. Chemotherapy drugs can be taken orally or injected into a vein (intravenously) so that they travel throughout your body. Chemotherapy drugs can also be administered into your spinal column, so treatment affects only your central nervous system.

Another type of chemotherapy can be placed during surgery. When removing all or part of the brain tumor, your surgeon may place one or more disk-shaped wafers in the void left by the tumor. These wafers slowly release a chemotherapy drug over the next several days.

Chemotherapy side effects depend on the type and dose of drugs you receive. Systemic chemotherapy can cause nausea, vomiting and hair loss.

Targeted drug therapy
Targeted drug treatments focus on specific abnormalities present within cancer cells. By blocking these abnormalities, targeted drug treatments can cause cancer cells to die. Many targeted drug therapies are very new and still undergoing careful study in clinical trials.

One targeted drug therapy used to treat brain tumors is bevacizumab (Avastin). This drug, given through a vein (intravenously), stops the formation of new blood vessels, cutting off blood supply to a tumor and killing the tumor cells.

Clinical trials
Clinical trials are studies of the latest treatments, such as new drugs or new ways of using existing drugs and new surgical techniques. A clinical trial may offer you a chance at the latest treatment advances. But clinical trials can't guarantee a cure. And, in some cases, side effects of new treatments may not be fully known.

Talk to your doctor about clinical trials. Together you can discuss the benefits and risks and decide if a trial is appropriate for you.

Rehabilitation after treatment
Because brain tumors can develop in parts of the brain that control motor skills, speech, vision and thinking, rehabilitation may be a necessary part of recovery. The brain can sometimes heal itself after trauma from or treatment of a brain tumor — but this can take time and patience.

• Cognitive rehabilitation can help you cope with or regain lost cognitive abilities.
• Physical therapy can help you regain lost motor skills or muscle strength.
• Vocational therapy can help you get back to work after a brain tumor or other illness.
• Specialists in speech difficulties (speech pathologists) are just one of many types of therapists who can help you recover.

School-age children with brain tumors may especially benefit from tutoring as a part of their overall treatment plan. A brain tumor can cause changes in the brain that affect thinking and learning. The earlier these problems are identified, the earlier they can be addressed with strategies that provide the most benefits to the child.

Alternative medicine

No complementary and alternative brain tumor treatments have been proved to cure brain tumors. However, they may help you cope with the side effects of your brain tumor and its treatment. Talk to your doctor about your options.

Some complementary and alternative treatments that may help you cope include:

• Acupuncture
• Massage
• Meditation
• Relaxation exercises
• Yoga