WHAT IS CHILDHOOD CANCER?

Childhood cancers are cancers that primarily affect children, teens and young adults. It is important to understand that when cancer strikes children and young people, it affects them differently than it does adults.

For example, young patients often have a more advanced stage of cancer when first diagnosed. Only about 20% of adults with cancer show evidence that the disease has spread at the time of diagnosis, yet 80% of children show that cancer has spread to distant sites in the body when the disease is first diagnosed.

While most adult cancers result from lifestyle factors, such as smoking, diet, occupation, and other exposure to cancer-causing agents, the causes of most childhood cancers, are not yet known. While 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 family physicians, consulting surgeons, medical oncologists or other cancer specialists. Cancers in children are rarely treated by family physicians or pediatricians. A child with cancer must be diagnosed precisely and treated by physicians and clinical and laboratory scientists who have special expertise in managing the care of children with cancer. Such teams are found only in major children's hospitals, university medical centers and cancer centers.

Types of childhood cancers
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, a 50% reduction in child deaths due to bone sarcoma was achieved due to research.

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. However, because of the difficulty in diagnosing and treating brain tumors, there has been less dramatic progress in treating them than other childhood malignancies. Today, 20% of all primary brain tumors arise in children younger than age 15, with a peak in incidence between the ages of five and 10 years. More boys than girls develop brain tumors.

Leukemias: Leukemia is cancer of the bone marrow and tissues that make the blood cells. When leukemia strikes, the body makes an abundance of abnormal white cells that do not perform their proper functions. Instead, they invade the marrow and crowd out normal healthy blood cells, making the patient susceptible to anemia, infection and bruising. The most common form of leukemia in young children is Acute Lymphoblastic Leukemia (ALL,) which laboratory and clinical research have achieved remarkable progress in fighting. About 70% of children can now be cured.

Lymphomas: Lymphoma is cancer which arises in the lymph system, the body’s circulatory network for filtering out impurities. There are two broad varieties of lymphomas: Hodgkin’s disease, and Non-Hodgkin’s lymphoma. Non-Hodgkin’s lymphoma is more common in children than is Hodgkin’s disease. Non-Hodgkins lymphoma 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. Today, treatments can cure many children, and other promising treatments are being developed to help even more young people.

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. Neuroblastoma attacks very young children. One-fourth of those affected show initial symptoms during the first year of life. Neuroblastoma spreads quickly, and is often discovered only after the disease is widespread. The early stages of neuroblastoma are curable by surgery alone. Researchers have discovered new, increasingly effective treatments for the advanced stages of the disease.

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 spread rapidly, its symptoms are quite obvious compared to other forms of childhood cancer. Overall prognosis for curing this disease has resulted from the development of improved chemotherapies.

Wilms' Tumor: This rapidly-developing tumor of the kidney most often appears in children, between the ages of two and four years of age. Wilms’ Tumor in children behaves differently than kidney cancer in adults. In children, the disease often metastasizes to the lungs. In the past, mortality from this cancer was extremely high. However, therapies that combine surgery, radiation therapy and chemotherapy, have been very effective in controlling the disease. As a result, cure rates for Wilms’ Tumor have risen sharply.

Retinoblastoma: A malignant eye tumor which occurs in infants and young children and shows a hereditary pattern, retinoblastoma accounts for only 2% of childhood cancer. This disease received a great deal of attention because it is the first cancer for which researchers identified a "tumor suppressor gene".

Other rare forms of childhood cancers include germ cell tumors, thyroid cancer, malignant melanoma, testicular tumors (usually during puberty,) and primary cancers in the kidney, liver, and lung.