Among teens and children, the most common cancer is leukemia. One of three people with cancer before adulthood have leukemia. Most young people with childhood leukemia gain a diagnosis of lymphocytic leukemia, while most of those not falling into this classification gain diagnosis of acute myeloid leukemia. Chronic leukemia rarely affects children.
Cancer develops from cells growing out of control in any part of the body. Cancer in blood-forming cells of the bone marrow is leukemia. Leukemia usually involves white blood cells but can also develop through red blood cells.
Any cell forming blood cells in spongy bone marrow tissue can become a leukemia cell. After such a cell mutation, the affected leukemia cells do not mature normally. Instead, they reproduce quickly and live too long. This causes an overflow of abnormal cells that outnumber normal cells, spilling into the bloodstream. These cells travel throughout the body and to the lymph nodes, brain, spinal cord, testicles, spleen, liver or other organs.
Childhood leukemia falls under acute or chronic types, although chronic leukemias more commonly affect adults. Acute leukemia grows quickly and chronic leukemia grows slowly. Acute leukemias include acute lymphocytic and acute myelocytic leukemia.
Acute lymphocytic leukemia affects about 75 percent of childhood leukemia patients. This type of leukemia affects immature lymphocyte cells in the bone marrow. Acute myelogenous leukemia makes up about 25 percent of childhood leukemia patients. This cancer begins in the myeloid cells forming non-lymphocyte white blood cells, red blood cells or platelets.
Some children gain diagnosis of rare leukemias called hybrid or mixed lineage leukemia. These feature cells of both acute lymphocytic and acute myelogenous leukemia.
Children usually have acute and not chronic leukemia. But chronic leukemia grows slowly and proves more difficult to treat when it occurs.
Another rare leukemia in children is juvenile myelomonocytic leukemia. This leukemia starts in myeloid cells but grows faster than chronic myelogenous leukemia and slower than acute myelogenous leukemia. This cancer occurs in very young children, those under the age of four. It creates symptoms like paleness, fever, cough, easy bruising, easy bleeding and breathing problems. It also causes enlargement of the spleen and lymph nodes.