The three types of blood cancers all involve an uncontrolled growth of abnormal cells within the blood and bone marrow. To understand what happens in blood cancer, it helps to know a little about the blood and lymphatic systems.
Blood carries oxygen and nutrients to all organs of the body, helps in healing and fights viruses, bacteria and other foreign material in the body. Blood is composed of:
- Plasma, the watery, yellowish fluid in which the blood cells are suspended and move through veins and arteries of the body
- Red blood cells, which contain hemoglobin, a body protein that carries oxygen to body tissues
- Platelets, the smallest cells that are responsible for clotting
- White blood cells (leukocytes), which protect the body from disease and infection
There are five main types of white blood cells, including lymphocytes. Lymphomas arise from lymphocytes, which are made in the lymph tissue, including the lymph glands, spleen, thymus, tonsils and bone marrow. Lymphocytes make up about 25% of all white blood cells. The number of lymphocytes circulating in the blood varies and can go either up or down when the body is fighting infection.
Lymph nodes are found along the lymphatic system, a network of thin tubes, similar to blood vessels, which branch into all parts of the body. The major external node clusters occur in the neck, armpit and groin. Lymph nodes become enlarged when you have a disease or infection. For instance, the lymph nodes in your neck may become swollen when you have a cold. Swollen lymph nodes often are not a sign of a serious problem, but this also is a symptom of lymphoma.
Leukemia and multiple myeloma may not result in swollen lymph nodes.
Leukemia usually starts in the bone marrow. Myeloma originates from a cell line called plasma cells, which are formed in bone marrow.
Responses to treatment and survival rates for each of these cancers also vary greatly.
The risk of developing blood cancers generally increases with age. Males are more susceptible than females. Because its exact cause hasn’t been discovered, there are no specific recommendations to prevent blood cancer, but you can follow general guidelines. Exposure to excessive radiation and hazardous chemicals should be limited. Studies show that benzene (found in unleaded gasoline), asbestos and pesticides may increase the risk of some blood cancers. When coming in close physical contact with benzene or other hazardous chemicals, take precautions by wearing protective clothing and gloves.