Cancer Health Article

Types of childhood cancers

The most common childhood cancers are leukemia, brain cancer, and lymphoma. Leukemia, which accounts for a third of the cancers diagnosed in children every year, affects the tissues that produce blood cells, causing a proliferation of abnormal white cells in the bone marrow. These crowd out the normal cells, interfering with blood clotting, leading to anemia, and making the child vulnerable to severe infections. Almost all cases of childhood leukemia, 97%, are acute and progress rapidly. Acute lymphocytic leukemia (ALL) is the most widespread type, accounting for 80-85% of cases in children. Leukemia usually strikes children between the ages of three and five. Symptoms include fatigue, pallor, fever, infections, abnormal bruising, bleeding gums, nosebleeds, and limping. The most effective treatment is chemotherapy to kill the abnormal white blood cells, accompanied initially by blood transfusions and antibiotics. Bone marrow transplants are becoming an increasingly frequent treatment method for this disease. After the diseased marrow is destroyed by radiation or chemotherapy, marrow cells from a compatible donor, usually a sibling, are transplanted into the patient. Treatment advances raised the survival rate for childhood leukemia from 4% in the 1960s to 70% by the 1980s.

Brain tumors are the second most common childhood cancer. Nearly half belong to one particular type, called an astrocytoma. If the tumor is in an operable location, the prognosis for 10-year survival is 80%. Hodgkin's disease and other cancers of the lymph system, or lymphomas, are also among the most frequent childhood cancers. Symptoms of lymphoma include fever, night sweats, swollen, tender lymph nodes, jaundice (yellowish skin and eyes), decreased appetite, and, in the case of Hodgkin's lymphoma, widespread itching. Current survival rates for lymphomas are excellent. With radiation and chemotherapy, the five-year survival rate for Hodgkin's disease is 90%, and the 10-year survival rate is 80%. Non-Hodgkin's lymphoma has a two-year survival rate (with treatment) of 70%, after which relapse is infrequent. With early detection and treatment, the survival rate for non-Hodgkin's lymphoma is as high as 90%.

Children can also develop various types of bone cancer. Two of the most common are osteosarcoma and Ewing's sarcoma. Adolescents, particularly adolescent boys, are especially prone to bone cancer, which tends to develop during growth spurts. The initial symptoms of a bone tumor—pain and swelling—may cause it to be mistaken for a bruise. If the cancer is allowed to progress untreated, it will eventually interfere with use of the affected part of the body—usually an arm or leg—and can make it sensitive to fractures. Although bone cancer is most commonly seen in the limbs, it can also occur in other locations, such as knees, hips, or shoulders. Bone cancer can develop in more than one location simultaneously or can spread from one part of the body to another. Bone tumors are generally diagnosed by a combination of χ ray and biopsy, in which a small amount of the tumor is removed for laboratory analysis. More sophisticated radiological procedures, such as a bone scan or a CAT scan (computed tomography, or CT), can aid in making a more detailed assessment and deciding on a course of treatment.

Surgery, followed by chemotherapy, is the treatment of choice for osteosarcoma. Usually the affected limb is amputated, although in some cases it is possible to remove only part of the limb, followed by reconstruction through a bone transplant or graft. Ewing's sarcoma is treated with radiation and chemotherapy but not surgery. Due to treatment advances, the prognosis for bone cancer—once considered an almost uniformly fatal illness—has improved dramatically in recent decades. The five-year collective survival rate for bone cancer is now 80%. As many as 50% of Ewing's sarcoma patients are likely to be long-term survivors of the disease. Similarly, the survival rate for osteosarcoma has risen to 50% from only 20% in the 1960s.

Another type of childhood cancer is Wilms' tumor, also known as nephroblastoma. Wilms' tumor is a kidney tumor originating from embryonal kidney cells that is most frequent in children under the age of five. A genetic component has been found in this disease, which is also associated with congenital urinary tract and genital deformities, such as undescended testicles. In most cases, the tumor is first detected as a lump in the abdomen or side. Other symptoms may include swelling, abdominal pain, appetite reduction, weight loss, fever, and urine in the blood. Without the standard treatment of surgery and chemotherapy, the tumor can spread to other organs, including the lungs and liver. Even if the tumor has spread, necessitating the removal of additional tissue besides the affected kidney, recovery from surgery is usually rapid. However, the child's health must be monitored regularly following treatment and recovery, as the tumor may recur, especially in the lungs. Since the 1960s the survival rate for Wilms' tumor has risen from 33% to over 80%.