Treatment of pediatric brain and spinal cord tumors
Treatment approaches for brain tumors vary depending on the type, location and stage of the tumor. The age and general health of the child are also considered. Treatment may include surgery, radiation therapy, and/or chemotherapy. Sometimes steroids are given to reduce swelling. Scientists are currently trying to find treatments that stimulate the body's own immune system to destroy tumor cells. Gene therapy is another treatment option being studied.
If the tumor is located in a area of the brain that will allow access to the tumor, a surgical biopsy or a needle biopsy will be done to remove a sample of tumor tissue so that doctors can study its characteristics. Some tumors are not biopsied prior to surgery. Instead, samples may be sent to pathology for analysis during the surgery for tumor removal.
To gain access to the brain, surgeons perform a craniotomy or craniectomy. "Cranio" means skull. "Otomy" means surgical incision. "Ectomy" means surgical removal. For a craniotomy, the surgeon creates a "bone flap" in the skull which is removed and put back in place when the operation is over. For a craniectomy, the bone is removed in pieces and not replaced.
If the tumor is located in a area of the brain where it's blocking the flow of the cerebrospinal fluid (CSF) pathway, removing the tumor will correct the problem. Sometimes, however, even when the CSF pathway is open, it doesn't function properly. In that case, the surgeon may insert a small plastic tube called a ventriculostomy or external ventricular drain (EVD) to avoid the buildup of fluid. Later, a more permanent internal shunt may be inserted to keep the fluid circulating around the brain. Sometimes steroids are given to reduce swelling before, during and after surgery.
The brain is a complex, sensitive organ, and doctors and parents must understand and deal with the risks of brain surgery. Despite the risk, surgery may be essential to remove as much of the tumor as possible. Studies show that two out of every 10 children who have brain surgery may develop serious after-effects. Examples include loss of speech, balance difficulties, hormonal disorders, or growth disorders. These problems may last for weeks, months, or longer. Speech therapy, physical therapy or occupational therapy can help restore function to maximum potential.
The ability of the pediatric neurosurgeon to remove as much of the tumor as possible is the first line of defense against a recurrence. Neurosurgeons commonly designate the extent of surgical resection (removal of tumor) as being total, near total, subtotal, partial, or biopsied only.
Total resection means that there are no visible residual tumor cells under the operating microscope or on the postoperative MRI, although there are always some tumor cells left behind. Therefore, some neurosurgeons refer to this as a "gross total" resection to distinguish it from the rare instances of a true total resection, in which the tumor as well as a margin of normal tissue are removed (which is rarely safe in the brain).
Near total means a small amount (less than 10%) of residual tumor is left behind. Subtotal means 50% to 90% tumor removal, and partial means less than 50% tumor removal.
Radiation therapy (RT)
Radiation therapy, also called radiotherapy, uses X-rays to attempt to destroy tumor cells. In cases where a tumor cannot be completely resected, survival rates improve when RT is used after surgery.
The side effects of RT vary from child to child and are most related to the dose administered and the age of the child. Radiation effects can be temporary or permanent, occurring at the time of treatment or months or years later.
Problems that can occur during radiation therapy include fatigue, nausea, diminished appetite, skin changes (like sunburn), hair loss, and difficulty swallowing. RT can cause low white blood cell counts (leaving the child susceptible to infection) or low levels of platelets (important for clotting and healing). Your radiation oncologist can often suggest ways to relieve some of the symptoms seen during radiation therapy.
Later effects of RT
- RT to the entire brain can cause learning problems noted several years after therapy. The effect of irradiation on learning and memory is quite variable, but in general is more pronounced when higher doses are used in younger children.
- Changes in growth can result from direct effects on spinal bone growth, or more commonly from a reduction in growth hormone. Growth hormone (GH) is an important substance produced at the base of the brain. GH is often diminished when measured a year or more after radiation therapy. In many cases, it can be replaced with a medicine.
- Changes in other hormones, including thyroid hormone and sometimes the hormones responsible for sexual maturation during puberty, can be noted at or beyond the one-year post-therapy point. When levels are inadequate, the hormones can be replaced with medication.
For some types of brain tumors, clinical trials are evaluating RT given in several small doses per day (hyperfractionated radiation therapy). Since radiation therapy can affect growth and brain development, other clinical trials are testing ways to decrease or delay radiation therapy, especially for younger children who aren't fully grown.
Chemotherapy is the use of a single medicine or combination of medicines to attack tumor tissue. It can be taken by mouth, injection, or through an intravenous line (IV). Some therapies can be given on an outpatient basis, while others require one or more days in the hospital.
Chemotherapy can be used to destroy tumor cells that remain after surgical removal of the tumor. It's often used if the patient is a child under 3 and the doctor wishes to delay or avoid RT. The treatment team may also use chemotherapy when they think that a second attempt at surgical resection may be feasible, because chemo may make the tumor more amenable to resection.
Among the side effects caused by chemotherapy are hair loss, skin problems, nausea, vomiting, diarrhea, constipation, changes in taste, fatigue, mouth sores, seizes, hearing loss, kidney and liver problems, and reduction of platelets, red cells, or white cells in the blood. Some of these problems may not occur at all. Some may be temporary, while others may be permanent. If your child requires chemotherapy, it's helpful to keep in mind that (1) children do not normally experience all possible side effects, and (2) there are ways to relieve or offset many of these side effects.
Research continues to improve the effectiveness and reduce the negative side effects of RT and chemotherapy. If you're interested in learning about clinical trails or studies that are testing new approaches, ask your doctor or contact the National Cancer Institute. You may also order free booklets about specific types of brain tumor and other free educational materials from us.