The major forms of blood cancer are lymphoma, leukemia and multiple myeloma. These cancers are formed either in the bone marrow or the lymphatic tissues of the body. They affect the way your body makes blood and provides immunity from other diseases.
Overall survival rates for people with blood cancer have doubled in the past 30 years because of more effective treatments. The cure rates are much higher for children than adults. In 1960, only 4% of children diagnosed with childhood leukemia survived. Today, more than 80% are expected to survive.
In most cases, the actual causes of blood cancer are still unknown. Scientists are trying to identify when and why the body starts producing abnormal cells and how those cells begin invading the body's blood system. As these questions are answered, the information is used to improve prevention and treatment options.
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 Strep throat or viral infection of your throat. Swollen lymph nodes are common and most often are not a sign of a serious problem. When lymph node swelling persists without any signs of infection, this could be caused by a more serious medical condition, such as lymphoma.
Leukemia may not result in swollen lymph nodes. Multiple myeloma almost never causes lymph node swelling unless there is also an infection present.
Leukemia and multiple myeloma starts in the bone marrow. Leukemia most commonly arises from abnormal lymphocytes or neutrophils. 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.
The cure rate for leukemias and lymphomas today is remarkable considering that the prognosis of most blood cancers 30 years ago was dreadful. Chemotherapy is usually the cornerstone of treatment. Radiation therapy is used for localized disease or to shrink tumor bulk that is compressing a vital body structure. Bone marrow transplants are being done with increasing frequency across the country. Newer treatments, such as biological therapies, are discovered at an exciting pace, and many are already used routinely in combination with other therapies.
Bone marrow transplants. Used more frequently to treat lymphoma and leukemia, this procedure gives very high doses of chemotherapy or irradiation, which kills the cancer cells, but also healthy cells in the bone marrow. The patient is then given an infusion of stem cells from the bone marrow or peripheral blood. Bone marrow transplant has tremendous risks, including death, and tends to be more successful in younger patients and when the disease is in an early stage. Since bone marrow transplant for blood cancers is a specialized procedure, a transplant candidate should look for a hospital that has extensive experience treating his or her specific type of cancer and that performs bone marrow transplants regularly.
Biological therapy. Biological therapy uses special immune system cells and proteins to stimulate the body's immune system to kill cancer cells. Biological agents such as interferons, interleukins, monoclonal antibodies, tumor-necrosis factors and colony-stimulating factors are natural substances found in the body that help alter the way the immune system reacts to cancer. Researchers now are able to create reproductions of some of these biological agents in laboratories. These reproductions imitate the natural immune agents and are used to augment the anti-tumor immune response of the patient.