Craniopharyngioma is a cancer which arises in the pituitary gland, in tissue originally found in the embryo. One of the most common childhood brain cancers, it is also sometimes called a Rathke's pouch tumor or a suprasellar cyst.
Description
Craniopharyngioma is the second most common type of childhood brain tumor, accounting for almost 10% of all brain tumors in children. This cancer has very little tendency to spread to other parts of the body. It readily invades local tissues, however, and since it occurs deep within the brain, invasion of local tissues alone can result in serious illness or even death.
The pituitary gland produces many hormones that play critical roles in the development and regulation of the body. Because this cancer arises in the pituitary gland, it often results in deficiencies of the various hormones that the pituitary gland produces. The tumor can be either solid or cystic or mixed, and most (up to 90%) of craniopharyngiomas contain calcium deposits, an indication of diseased tissue readily observable on x rays.
Demographics
The large majority of craniopharyngiomas are childhood tumors. The median age at diagnosis is eight years; peak incidence is between the ages of six and eleven. Almost 70% of all craniopharyngiomas occur before the age of 20, although a small peak occurs after the age of 50. Diagnosis before the age of two is very rare. Girls and boys and all races are affected equally.
Causes and symptoms
The cause of craniopharyngioma is not really understood, although it is believed to be primarily a congenital illness. Nests of embryonic cells exist in a part of the pituitary gland known as Rathke's pouch. In craniopharyngioma, these nests appear to contain cancerous cells which, over time, multiply and become a tumor.
The symptoms of craniopharyngioma can be divided into two categories. Some are nonspecific symptoms which occur because of increased pressure within the skull; some result from deficiencies of the hormones that the pituitary gland normally produces. Any individual patient may have various combinations of symptoms and both the number of symptoms and the severity of the symptoms typically increase over time. Nonspecific symptoms of increased intracranial pressure include:
Most patients seek medical attention because of headaches or visual disturbances, failure to match normal growth patterns (due to a deficiency of growth hormone), or symptoms of diabetes. If (after other causes of symptoms are ruled out) a craniopharyngioma is suspected, usually some kind of imaging technique is performed. Traditional x rays reveal an enlargement of the space at the base of the skull where the tumor is typically found, and will also show calcification of cancerous cells. Computed tomography (CT scan or CAT scan) may show calcification that does not show up on x rays and also shows whether the tumor is cystic or solid in nature. Magnetic resonance imaging (MRI) can show how much the tumor has invaded the surrounding tissues.
Often the amounts of pituitary hormones in the blood are measured as well. Measurements may be made of gonadatropins (hormones which regulate reproduction), thyrotropin (a hormone that regulates the thyroid gland), growth hormones (regulates growth), corticotropin (a hormone that regulates carbohydrate metabolism, vasopressin (a hormone that regulates water retention), or prolactin (a hormone that regulates milk production in mothers of infants).
Treatment team
As the understanding of cancer grows and new treatment approaches are developed, the complexity of cancer treatment also increases. Today, a multidisciplinary approach to cancer treatment is considered necessary for effective patient care. Since craniopharyngioma is a neuroendocrine tumor that occurs deep in the brain and mainly in children, optimal treatment requires a particularly complex and sophisticated team of health professionals. The types of people who may be involved in treating or caring for a patient with craniopharyngioma and their family typically include oncologists (pediatric), pathologists (neuropathologists), radiation oncologists, radiation technicians, psychiatrists, oncology social workers, nutritionists, home health care providers, endocrinologists, rehabilitative specialists, and neurosurgeons. The surgeon, specifically, should be a pediatric neurosurgeon, as these specialists have been shown to provide better long-term outcomes than general neurosurgeons.
Clinical staging, treatments, and prognosis
Standard treatment for craniopharyngioma consists of surgical removal of as much of the tumor as is readily accessible, followed by radiation therapy. Although total removal of the tumor yields the best odds of survival, the location in which this cancer occurs (and the fact that these tumors are typically covered by a thick membrane that adheres tightly to surrounding tissues) can make total removal difficult. Attempts to remove the tumor completely, therefore, often result in significant and unacceptable side effects. A better quality of life, and therefore better overall outcome, is obtained through partial removal of the tumor followed by radiation therapy. This is now generally accepted as the best treatment approach.
Chemotherapy is not routinely used for treatment of craniopharyngioma, although some medications are commonly used to treat symptoms. Drugs that decrease inflammation and reduce the probability of convulsions may be given preoperatively to make surgical removal of the tumor safer. Hormone replacement therapy may be necessary if the cancer, occurring in the pituitary gland, causes serious hormone deficiency problems.
Therapies that are not routinely used but have shown some promise include internal placement of radioactive material and improvements in surgical techniques, including stereotactic surgery, which utilizes a radioactive "gamma knife" for excision of the tumor.
Since this type of cancer does not demonstrate a tendency to spread to remote areas of the body, staging or grading systems are not usually used. Factors that improve survival are complete removal of the tumor (although this often results in greatly decreased quality of life), the size of the tumor at diagnosis, a cystic rather than solid nature of the tumor, and an age of at least five years old at diagnosis. Unfortunately, most patients who survive have significant remaining illness, and predicting how much function may be lost is as important in this cancer as prognosis of survival. It is important to remember, especially with regards to extent of functional capacity to be expected, that the physician's prognosis is only an educated guess, and that positive thinking can contribute significantly to a better quality of life.
Alternative and complementary therapies
Alternative and complementary therapies are treatments which are not traditional, first-line therapies like surgery, chemotherapy and radiation. Complementary therapies are those that are meant to supplement traditional therapies and usually have the objective of relieving symptoms or helping cancer patients cope with the disease or traditional treatments. Alternative therapies are nontraditional treatments which are chosen instead of
traditional treatments in an attempt to cure the disease. Alternative therapies have typically not been proven to be effective in the same way that traditional drugs are evaluated, in studies called clinical trials, and are usually not recommended for use with children.
Common complementary therapies that may be employed by cancer patients include aromatherapy, art therapy, massage, meditation, music therapy, prayer, t'ai chi, and yoga or other forms of exercise, which reduce anxiety and can increase a patient's feeling of well-being. Many patients also take high doses of vitamins and other nutritional supplements, especially A, C, E, and selenium, which are thought to act as antioxidants. Any physical activities or nutritional supplements (especially when treating a child) should be discussed with then patient's physician.
Numerous alternative therapies exist in cancer treatment. Special caution must be used, however, when considering alternative therapies for children's cancers. Although alternative treatments, by definition, have not been proven effective by scientific methods, some brain tumor patients believe that the use of alternative therapies has been beneficial. Some alternate therapies include:
Laetrile, a product of apricot seeds, contains a form of cyanide that proponents believe may be released by tumor enzymes and act to kill cancerous cells. Laetrile is not approved by the Food and Drug Administration for use in the United States. The National Cancer Institute sponsored two studies of laetrile in the late 1970s and early 1980s, but concluded after the second study that no additional research was necessary.
Vitamin E, melatonin, aloe vera, and a compound called beta-1, 3-glucan are reported to stimulate the immune system. Some practitioners believe that natural substances like garlic, ginger, and shark cartilageshrink tumors, although how they are supposed to work is not really defined.
Antineoplastons are believed by some to be another alternative approach to a cancer cure. Antineoplastons are small proteins which may act as molecular messengers and which may be absent from the urine and blood of many cancer patients. The therapy is based on the idea that replacing these proteins may have beneficial effects. However, the National Cancer Institute proposed phase II clinical trials, and protocols were developed, but the trials never got underway on a large scale because of lack of patient participation. The National Cancer Institute draws no definitive conclusions about the treatment's effectiveness due to lack of clinical trials.
Coping with cancer treatment
Children have special needs when coping with treatment, depending on their age. Some comprehensive resources are available about how families can cope with cancer diagnoses, but some coping strategies are summarized here. Very young children need affection, soothing, time to play, reassurances, while toddlers have these same needs, but also may need to be taught how to express their anger or frustration, and simple explanations about what is happening. School-age children may enjoy a little more involvement in their treatment plan, and will need empathy about missing school and activities. They may benefit from drawing or keeping a journal, communicating with friends, and, if possible, a little physical activity each day. Adolescents have similar needs, but also may want to keep some thoughts and feelings private, and also may have more complex spiritual concerns along with feelings of anger and frustration. The siblings and parents of the child with cancer will have needs and concerns and will need to adopt coping strategies as well. The patient's treatment team can help point the family to helpful resources.
Treatment of craniopharyngioma commonly includes surgery and radiation therapy. Although the use of radiation therapy in addition to surgery has improved
the quality of life for craniopharyngioma patients, treatments unavoidably result in damage to some healthy tissues and other undesirable side effects.
Fatigue is a very common side effect of radiation therapy. Patients should expect to be very sleepy and therefore to cut back on activities, allowing plenty of time for resting and letting the body heal. It is also important to try maintain a well-balanced, nutritious diet. Patients should avoid as much extra stress as possible and should limit visitors, if needed, to avoid being overtired.
Another problem for those undergoing radiation therapy is dry, sore skin in the area being treated. (Radiation does not hurt during treatment and does not make the person radioactive.) Skin in the treatment area is essentially "burned" and may blister and peel, becoming painful. Patients with fair skin or those who have undergone previous chemotherapy have a greater risk of more serious reactions. Dry, itchy or sore skin is temporary, but skin in the treatment area may remain more sensitive to sun exposure, so a good sunscreen should be used whenever affected skin is exposed to sunlight.
Radiation therapy requires a substantial level of commitment from the patient in terms of time and emotional energy. Fear and anxiety are major factors in coping with cancer in general and these cancer treatments specifically. The feelings are completely normal. Some patients find that concentrating on restful, pleasurable activities like hobbies, prayer, or meditation is helpful in decreasing negative emotions. It is also very important that patients have people to whom they can express their fears and other negative emotions. If friends or family members are unable to provide this to patients, support groups may help to provide an environment where fears can be freely expressed and understood.
Clinical trials
Although numerous clinical trials are in progress which evaluate treatments for childhood brain tumors, few of these are specifically concerned with craniopharyngioma. Most clinical trials for childhood brain tumors are evaluating new medications or new chemotherapy combinations. Although some of these may prove effective against craniopharyngiomas, chemotherapy at this time is not considered an appropriate approach to treatment of this disease. Some new therapies with potential value for cranipharyngioma patients include new forms of drug delivery, including liposomes, and immune-based therapies like monoclonal antibodies. In addition, new refinements of surgical techniques, including MRI-assisted surgery and stereotactic surgery, including the bloodless "gamma knife" surgery, are being evaluated. A clinical trial evaluating a pharmaceutical therapy for a common
side effect of surgical treatment of craniopharygioma, hypothalmic obesity, is ongoing.
Prevention
Craniopharyngioma is believed to be a congenital disease, and there is no known way to prevent this cancer.
Special concerns
This tumor is characterized by various diseases related to hormone deficiencies which may arise as the result of the tumor itself or as the result of either surgical or radiation therapy. The tumor may cause problems related to hormone deficiencies, especially diabetes or growth retardation, and these are often the reason that medical attention is first sought. Craniopharyngioma patients may also experience sleep disorders, changes in personality, and mental disturbances. In addition, treatment for craniopharyngioma can create a condition called hypothalmic obesity, in which a patient steadily gains weight although eating patterns may not have changed. Although many of these problems may significantly improve with time, care of a family member with a brain tumor is a significantly stressful experience for caregivers, which creates a huge strain on normal family life.
As mentioned, childhood cancers create unique concerns for the children diagnosed and their families. Parents and siblings, as well as the cancer patient, all have emotional issues to address, in addition to everyday
concerns, such as social development, friends, and school. Hospital staff and social workers can help direct a family to useful resources for support. Support groups for craniopharyngioma patients and for parents of craniopharyngioma patients offer patients and parents a place to discuss their fears and concerns with other people who have been impacted by this disease.
Resources
BOOKS
Abeloff, ed. Clinical Oncology. New York: Churchill Livingstone.
Bracken, Jeanne Munn. Children with Cancer: A Comprehensive Reference Guide for Parents. New York:Oxford University Press, 1986.
Buckman, R. What You Really Need to Know About Cancer. Baltimore: Johns Hopkins University Press, 1999.
Cook, Allan R., ed. The New Cancer Sourcebook. New York:Omnigraphics, Inc., 1996.
Fromer, Margot Joan. Surviving Childhood Cancer: A Guide for Families. Washington D.C.: American Psychiatric Press, 1998.
Ganz, Pam. Life Isn't Always A Day at the Beach: A Book for All Children Whose Lives Are Affected by Cancer. Lincoln, Nebraska: High-Five Publishing, 1996.
Pizzo and Poplack, eds. Principles and Practice of Pediatric Oncology. Baltimore, MD: Lippincott-Raven Publishers, 1997.
PERIODICALS
Lafferty, A. R. "Pituitary Tumors in Children and Adolescents."Journal of Clinical Endocrinology and Metabolism 84 (December 1999):4317-4322.
ORGANIZATIONS
American Cancer Society, 1599 Clifton Road, NE, Atlanta, GA30329-4251. (800)586-4872 <http://www.cancer.org>
National Cancer Institute, 9000 Rockville Pike, Bethesda, Maryland, 20892. (800)422-6237. <http:..www.nci.nih.gov>
