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What is a “blood cancer”?

Leukemia, lymphoma, and myeloma are types of cancer that fall into the general category of hematological malignancies. They generally affect the blood, bone marrow or lymph nodes.

Leukemia

Leukemia is a general term for cancer of the blood or bone marrow characterized by an abnormal production of blood cells. It is divided into four types:

Acute leukemia (acute myelogenous leukemia and acute lymphocytic leukemia): In acute leukemias, immature blood cells in the bone marrow crowd out normal cells. These nonfunctional cells spill over into the blood stream and spread to other organs in the body. Acute leukemia is the most found leukemia in children. Acute leukemia progresses very rapidly and requires immediate treatment.

Chronic leukemia (chronic myelogenous leukemia and chronic lymphocytic leukemia): In chronic leukemias, relatively mature, but abnormal, blood cells multiply excessively over a period or months or years. The number of red cells is generally less than normal, causing anemia. The number of white cells can be much higher than normal. Chronic leukemia occurs most often in older people.

Both acute and chronic leukemias are further subdivided according to what kind of blood cell is affected. All leukemias begin with a leukemic change to a cell in the bone marrow. The cancerous cell multiplies and survives better than normal cells and eventually crowds out the normal cells.

In lymphocytic leukemias (ALL and CLL), the cancerous change occurs in a type of marrow cell that forms lymphocytes, a type of white blood cell that is part of the immune system. In myelogenous leukemias (AML and CML), the change occurs in a type of marrow cell that forms red blood cells, other white blood cells, and platelets.

Lymphoma

Lymphoma is the name for a group of blood cancers that originates in the lymphatic system. The lymphatic system is part of the body’s immune system and its defense against infection. Lymphoma begins with a change to a lymphocyte, which causes it to become a lymphoma cell. These lymphoma cells multiply and become masses in the lymph nodes, causing an enlargement of the nodes. The two main types of lymphoma are Hodgkin’s and non-Hodgkin’s lymphomas (NHL).

Hodgkin’s lymphoma: In Hodgkin’s lymphoma, cells in the lymphatic system grow abnormally and may spread beyond the lymphatic system. Hodgkin’s lymphoma is marked by the presence of a type of large malignant cells called Reed-Sternberg cells. The two major types of Hodgkin lymphoma are classical Hodgkin lymphoma and nodular lymphocyte-predominant Hodgkin lymphoma. As Hodgkin’s lymphoma progresses, it compromises the body’s ability to fight infection. Symptoms include the painless enlargement of lymph nodes, spleen, or other immune tissue. Other symptoms include fever, weight loss, fatigue, or night sweats. Advances in the diagnosis and treatment of Hodgkin’s lymphoma have helped to make this once uniformly fatal disease highly treatable, with the potential for full recovery.

Non-Hodgkins lymphoma: Non-Hodgkin’s lymphoma is much more common than Hodgkin’s disease. It represents a diverse group of diseases that are distinguished by the characteristics of the cancer cells associated with each disease type. These types can be divided into fast-growing and slow-growing and can be formed from either B-cells or T-cells. The most common symptoms are one or more enlarged lymph nodes in the neck, armpit, or groin. Other symptoms can include swollen lymph nodes, fever night sweats, feeling tired, loss of appetite, weight loss, and rash. Prognosis and treatment depend on the stage and type of disease.

Myeloma

Myeloma is a type of cancer that begins in the bone marrow and affects the plasma cells. Myeloma belongs to a spectrum of disorders referred to as “plasma cell dyscrasia.” and has several forms:

Multiple myeloma is most common – more than 90 percent of people with myeloma have this type. Multiple myeloma affects several different areas of the body.

  • Plasmacytoma – in this type, only one site of myeloma cell accumulation is apparent within the body, such as a tumor in the bone, skin, muscle, or lung.
  • Localized myeloma – this type of the disease is present in one site of the body that is exposed to neighboring sites.
  • Extramedullary myeloma – this type involves bodily tissue other than bone marrow, such as the skin, muscles, or lungs.

Doctors divide myeloma into groups that describe how rapidly or slowly the disease is progressing:

  • Asymptomatic or smoldering myeloma progresses slowly and has no symptoms even though the patient has the disease.
  • Symptomatic myeloma has related symptoms such as anemia, kidney damage and bone disease.

Other Resources

More information and patient support can be found through the following organizations:

  • Leukemia & Lymphoma Society
  • Lymphoma Research Foundation
  • National Cancer Institute
  • National Heart, Lung, and Blood Institute
  • Be The Match
  • CanCare