Spring 2003
Childhood Cancer is Different
The cancers that attack children are different from the principal cancers of adults.
Children frequently have a more advanced stage of cancer when they are first diagnosed. Only about 20% of adults with cancer show evidence that the disease has spread at the time of diagnosis, yet 80% of the children who are diagnosed with cancer have disease which has already spread to distant sites in the body.
Most adult cancers result from lifestyle factors, such as smoking, diet, occupation, and other prolonged exposure to cancer-causing agents. The causes of most childhood cancers are not yet known.
Adult cancers are primarily those of the lung, colon, breast, prostate and pancreas. Childhood cancers are mostly those of the white blood cells (leukemias), brain, bone, the lymphatic system, and tumors of the muscles, kidneys and nervous system. Each of these behaves differently, but all are characterized by an uncontrolled proliferation of abnormal cells.
The majority of adult cancer sufferers are treated in their local community by their family physician, consulting surgeons, medical oncologists or other cancer specialists. Children with cancer rarely are treated by family physicians or pediatricians. A child with cancer must be diagnosed precisely and treated by teams of clinical and laboratory scientists who have expertise in the management of children with cancer. Such teams are found only in major children's hospitals, university medical centers and cancer centers.
PRINCIPAL CANCERS OF CHILDREN
TYPES OF CHILDHOOD CANCER
BONE CANCERS
The bones may be the site to which other cancers spread, but some types originate in the skeleton. The most common bone cancer is osteogenic sarcoma. Bone cancer in children occurs most often during adolescent growth spurts, and 85% of those teenagers have tumors on their legs or arms, half of them around the knee. Ewing’s sarcoma differs from osteosarcoma in that it affects the bone shaft, and tends to be found in bones other than the long bones of the arm and the leg, such as the ribs. During the period from 1950 to 1980, there was a 50% reduction in deaths in children due to bone sarcoma.
BRAIN TUMORS
Tumors of the brain and spinal cord are the most common types of solid tumors in children. Some tumors are benign, and some children can be cured by surgery. But there has been less dramatic progress in treating brain cancer tumors than most other childhood malignancies because they are hard to diagnose and treat. Twenty percent of all primary brain tumors arise in children younger than age 15, somewhat more in boys than girls. There is a peak in incidence between the ages of 5 and 10.
LEUKEMIAS
Leukemia is cancer of the tissues of the body which make the blood cells and the bone marrow. When leukemia strikes, the body makes an abundance of abnormal white cells that do not perform their proper functions. They invade the marrow and crowd out the normal healthy blood cells, making the patient susceptible to infection and bruising. The most common form of this disease in young children is Acute Lymphoblastic Leukemia (ALL) which medical science has made remarkable progress in fighting.
LYMPHOMAS
Lymphoma is cancer which arises in the lymph system, the body’s circulatory network for filtering out impurities. There are two broad varieties, Hodgkin’s disease, and Non-Hodgkin’s lymphoma. Non-Hodgkin’s lymphoma is more common in children than Hodgkin’s disease. It can arise in the tonsils, thymus, bone, small intestine, spleen, or in lymph glands anywhere in the body. The disease can spread to the central nervous system and the bone marrow. Treatments have been developed that can cure many children, and other promising treatments are coming along.
NEUROBLASTOMA
Found only in children, neuroblastoma arises in the adrenal glands, located in the abdominal area near the kidneys, and along the sympathetic nerve chain in the chest and abdomen. It attacks very young children. One-fourth of those affected show initial symptoms during the first year of life. Neuroblastoma spreads quickly, and often is discovered only after the disease is widespread. Early stages are curable by surgery alone. Researchers have discovered new treatments for advanced stages which are increasingly effective.
RHABDOMYOSARCOMA
The most common soft tissue sarcoma in children, this extremely malignant neoplasm originates in skeletal muscle. Although it can occur in any muscle tissue, it is generally found in the head and neck area (including the eye socket), the genito-urinary tract, or in the extremities. Although rhabdomyosarcoma tends to grow and spread very rapidly, fortunately its symptoms are quite obvious compared to other forms of childhood cancer. Overall prognosis is improving, with the development of improved chemotherapies.
WILMS’ TUMOR
This rapidly-developing tumor of the kidney most often appears in children, usually between the ages of two and four, and is very different from adult kidney cancers. The disease often metastasizes to the lungs, and in the past, the mortality from this cancer was extremely high. However, newer therapies have been very effective in controlling it, combining surgery, radiation therapy and chemotherapy, and cure rates have risen sharply.
OTHER
Retinoblastoma -- a malignant eye tumor which occurs in young children and shows a hereditary pattern -- accounts for only 2% of the childhood cancer cases. However, it received a great deal of attention when it was the first cancer for which researchers were able to identify the responsible gene. There are many other childhood cancers that are even more rare, including germ cell tumors, thyroid cancer, malignant melanoma, testicular tumors (usually during puberty,) and primary cancers in the kidney, liver, and lung.
About Childhood Cancer
Currently one in every 330 children in the United States develops cancer before the age of nineteen.
Progress in the development of effective new treatments and cures for children with cancer has been spectacular during the past three decades, but progress is beginning to plateau. Most children now can be cured if they are treated at childhood cancer treatment and research centers by teams of experts in childhood cancer. But many types of childhood cancer have not yet yielded to research progress.
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