Types of Cancer
The types of cancers that occur most often in children are different from those seen in adults. The most common cancers of children are:
• Brain and other nervous system tumors
• Wilms tumor
• Bone cancer
Leukemias are cancers of the blood or bone marrow and are the most common childhood cancers. They account for about 34% of all cancers in children. The most common types in children are acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML). Leukemia may cause bone and joint pain, weakness, bleeding, fever, weight loss, and other symptoms.
Brain and Nervous System Tumors
There are many types of brain and nervous system tumors and they are the second most prevalent cancer in children. Most brain tumors in children start in the lower parts of the brain, such as the cerebellum or brain stem. They can cause headaches, nausea, vomiting, blurred or double vision, dizziness, and trouble walking or handling objects. Neuroblastoma is a form of cancer that starts in certain types of nerve cells found in a developing embryo or fetus. It is rarely found in children older than 10.
Wilms tumor is a cancer of the kidney. It is most often found in children about 3 years old, and is uncommon in children older than age 6. It can show up as a swelling or lump in the abdomen.
Lymphomas are cancers that start in lymph tissues, like the lymph nodes, tonsils, and thymus. They may spread to bone marrow and other organs, which can cause different symptoms depending on where the cancer is growing. There are 2 main types of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. Both types can occur in both children and adults.
Rhabdomyosarcoma starts in cells that normally develop into skeletal muscles. This is the most common type of soft tissue sarcoma in children. It makes up about 3% of childhood cancers.
Retinoblastoma is a cancer of the eye and causes a loss of vision. Retinoblastomas are usually found because a parent or doctor notices a child's eye looks unusual.
Primary bone cancers (cancers that start in the bones) occur most often in older children and teens, but they can develop at any age. Two main types of primary bone cancers occur in children:
• Osteosarcoma accounts for about 3% of all new childhood cancer cases in the United States. It is most common in teens, and usually develops in areas where the bone is growing quickly, such as near the ends of the long bones in the legs or arms. It often causes no pain or symptoms until swelling starts, but sometimes there is bone pain that gets worse at night or with activity.
• Ewing sarcoma is a less common primary bone cancer, which can also cause bone pain. It is most often found in young teens. The most common places for it to start are the bones in the pelvis, the chest wall or in the middle of the long leg bones. Ewing sarcoma accounts for about 1% of childhood cancers.