Brain Tumors

Signs and Symptoms

Brain tumors may be benign or malignant.

Benign tumors don't contain cancer cells. If completely removed by surgery, they often don't recur. Benign tumors that can't be completely removed, however, may continue to grow and may require treatment such as chemotherapy or radiation treatment.

Malignant or cancerous brain tumors usually grow quickly, spread to surrounding tissue and may recur after treatment.

The majority of brain tumors are caused by genetic abnormalities within the tumor cells. Researchers are studying the parents of children with brain tumors and their exposure to certain chemicals. Some chemicals may change the structure of a gene that protects the body from cancer. Workers in oil refining and rubber manufacturing and chemists have a higher incidence of certain tumors. In addition, children who have received radiation therapy to the head as part of treatment for other malignancies have a higher risk for developing brain tumors.

There are two types of brain tumors -- primary and secondary.

Primary Tumors

Tumors that begin in brain tissue are known as primary brain tumors. The most common brain tumors are gliomas, which begin in the glial or supportive, tissue. There are several types of gliomas including:

• Astrocytomas arise from small, star-shaped cells called astrocytes. They may grow anywhere in the brain or spinal cord. In children, they occur in the brain stem, the lowest stem-like part of the brain that connects to the spinal cord; the cerebrum, the upper part of the brain that controls mental processes; and the cerebellum, the lower part of the brain that controls coordinated movement and possibly even some forms of cognitive learning. Astrocytomas can be either low grade, usually benign, or high grade, which are malignant.

• Brain stem gliomas occur in the lowest, stem-like part of the brain that connects to the spinal cord. The brain stem controls many vital functions. Tumors in this area generally can't be removed. Most brain stem gliomas are high-grade astrocytomas.

• Ependymomas usually develop in the lining of the ventricles or cavities of the brain. They also may occur in the spinal cord. Although these tumors can develop at any age, they are most common in childhood and adolescence.

Other types of primary brain tumors that do not begin in glial tissue include:

• Medulloblastomas are malignant tumors that are thought to develop from developing nerve cells that normally don't remain in the body after birth. Most medulloblastomas arise in the cerebellum, the lower part of the brain that controls coordinated movement and possibly some forms of cognitive learning, as well as in other areas of the brain. These tumors most often occur in children and are more common in boys than girls. A related tumor called supratentorial primative neuroectodermal tumor (SPNET) occurs in the cerebral hemispheres or the upper parts of the brain that control mental processes.

• Craniopharyngiomas develop in the region of the pituitary gland near the hypothalamus that regulates body heat and other vital functions such as food intake. These tumors most often occur in children and adolescents and are usually benign.

• Germ cell tumors arise from developing sex cells or germ cells. The most frequent germ cell tumor in the brain is the germinoma. Germ cell tumors account for about 3 percent of all cancer in children and adolescents.

• Pineal region tumors occur in or around the pineal gland, a tiny organ near the center of the brain that affects hormones and other functions. This tumor can be slow growing, called pineocytoma, or fast growing, called pineoblastoma. Pineoblastoma, which is a malignant tumor, is in the same family of tumors as supratentorial primitive neuroectodermal tumors (SPNET). 

• Choroid plexus tumors arise from tissues that make cerebrospinal fluid that surrounds and protects the brain and spinal cord. These tumors are rare, representing only 3 percent of pediatric brain tumors but account for 10 percent to 20 percent of the tumors that occur in the first year of life. There are two forms choroid plexus papillomas, which is slow growing, or choroid plexus carcinomas, which is more aggressive in growth. They occur most frequently in infants and young children.

Secondary Brain Tumors

Cancer that begins in other parts of the body but spread to the brain are called secondary brain tumors. For example, if lung cancer spreads to the brain, it is a secondary brain tumor resulting from metastatic lung cancer. The cells in the secondary tumor resemble abnormal lung cells, not abnormal brain cells. Secondary brain tumors are rare in children, accounting for less than 5 percent of those occuring in children. 

Symptoms

Symptoms are caused by damage to vital tissue and pressure on the brain as the tumor grows within the limited space in the skull. Symptoms also may arise because of a condition called edema, a swelling and buildup of fluid around the tumor, or due to hydrocephalus, which occurs when the tumor blocks the flow of cerebrospinal fluid and causes it to build up in the ventricles. If a brain tumor grows very slowly, its symptoms may appear so gradually that they are overlooked for a long time. Symptoms vary with the size and location of the tumor.

The most frequent symptoms are:

• Headaches that tend to be worse in the morning and ease during the day
• Seizures or convulsions
• Nausea or vomiting
• Weakness or loss of feeling in the arms or legs
• Stumbling or lack of coordination in walking (ataxic gait)
• Abnormal eye movements or changes in vision
• Drowsiness
• Changes in personality or memory
• Changes in speech

These symptoms may be caused by brain tumors or by other problems. Only a doctor can make a diagnosis.

Diagnosis

Diagnosis of a brain tumor depends mostly on the types of cells in which the tumor begins and the tumor location. Diagnostic procedures for a brain tumor may include the following:

• Neurological Exam Your child's doctor will test reflexes, muscle strength, eye and mouth movement, coordination and alertness.

• Computed Tomography Scan (CT or CAT scan) This is a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images, both horizontally and vertically, of the body. A CT scan shows detailed images of the body, including the bones, muscles, fat and organs. CT scans are more detailed than general X-rays.

• Magnetic Resonance Imaging (MRI) This is a diagnostic procedure that uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body. An MRI may require sedation or anesthesia for young children.

• X-ray X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones and organs onto film.

• Bone Scan These pictures or X-rays are taken of the bone after a dye has been injected that is absorbed by bone tissue. These are used to detect tumors and bone abnormalities.

• Lumbar Puncture or Spinal Tap A special needle is placed into the lower back in the spinal canal, the area around the spinal cord. A small amount of cerebral spinal fluid (CSF) is removed for testing. CSF is the fluid that bathes the brain and spinal cord. A lumbar puncture may require sedation or anesthesia for young children.

Treatment

Treatment options for primary brain tumors include:

• Surgery When possible, surgery is performed to remove tumors.
  
  
• Radiation Therapy The use of high-dose X-rays to kill cancer cells and shrink tumors. Radiation therapy for childhood brain tumors usually comes from a machine and is called external radiation therapy.
  
  
• Radiosurgery Gamma Knife radiosurgery is a minimally invasive option for children with small to medium tumors deep within the brain. Radiosurgery differs from conventional radiation treatment in that small, targeted doses of radiation are delivered to the brain, with little damage to surrounding tissue.
  
  
• Chemotherapy The use of drugs to kill cancer cells. Chemotherapy drugs may be taken orally or injected into a vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body and can kill cancer cells throughout the body.

More than one type of treatment may be used, depending on the needs of your child.  Children who undergo treatment at UCSF Children's Hospital receive specialized care from imaging studies to anesthesia to recovery provided by pediatric specialists. Your child's treatment may be coordinated by a pediatric oncologist, a doctor who specializes in brain tumor treatment in children. The oncologist may refer your child to other doctors, such as a pediatric neurosurgeon, who is a specialist in childhood brain surgery,  a pediatric neurologist, a psychologist, a radiation oncologist and other doctors who specialize in the type of treatment your child requires.

Astrocytomas

Surgery to remove all or as much of the tumor as possible is the primary treatment for childhood cerebellar astrocytoma. If the tumor can't be completely removed, radiation therapy may be given. Because radiation therapy can affect a child's growth and development, chemotherapy may be given to try to delay or eliminate the need for radiation therapy, depending on the age of the child. The prognosis for children with cerebellar astrocytoma that has been completely surgically removed is generally good, with a 95 percent survival rate for five to 10 years.

Some forms of low grade astrocytoma may not be easily removed and may be treated with chemotherapy, radiation treatment or both, depending on the age and symptoms of the child.

Brain Stem Gliomas

Surgery is used when possible to treat brain stem glioma, but tumors in the brain stem often can't be surgically removed. Your child's doctor may remove as much of the tumor as possible by creating an opening in the skull in an operation called a craniotomy. Surgery, however, may be limited to a biopsy. Sometimes, no surgical procedure can safely be performed, in which case the diagnosis is made based on the MRI appearance of the tumor. The prognosis for children with brain stem gliomas is generally poor, with a 10 percent survival rate two years from the time of diagnosis.

Ependymomas

Depending on the tumor's location, your child's doctor may remove as much of the tumor as possible by creating an opening in the skull in an operation called a craniotomy. If the ependymoma is in a place where it can't be removed, surgery may be limited to a biopsy or partial removal of the tumor.

Chemotherapy is being studied as a means of delaying or eliminating the need for radiation therapy in young patients as well as for use prior to or during radiation therapy. UCSF Children's Hospital is participating in clinical research to find new ways of using radiation treatment to reduce the side effects in children. The prognosis for children with ependymomas varies widely, depending on the characteristics of the tumor and other factors.

Medulloblastoma

Researchers are studying different chemotherapy drugs for childhood medulloblastoma. Stem cell transplantation, which returns a child's blood cells after high-dose chemotherapy, may be considered if your child's tumor recurs after surgery, radiation and chemotherapy, or if your child is very young and at risk for complications from standard radiation therapy.

The prognosis of medullobastoma varies, depending on the age of the child at the time of diagnosis, the amount of tumor that can be removed and whether the tumor has spread beyond the primary site at the time of diagnosis.