Hematologic Malignancies

Hematologic malignancies are cancers that arise in the bone marrow or lymphatic tissues. They include Hodgkin’s disease, non-Hodgkin lymphoma (NHL), leukemia, myeloma and myelodysplastic syndromes. Although these cancers are distinct from one another with respect to the cell types from which they originate, treatments and prognoses, they are considered to be related because they arise in cells that have similar functions and origins.

The Leukemia & Lymphoma Society estimates that 139,860 new cases of leukemia, lymphoma or myeloma were diagnosed in 2009, and that 53,240 people died of these diseases in the same time period.

Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma (NHL) is a cancer that arises in lymphocytes, key components of the immune system. It is one of the most common cancers, and the American Cancer Society estimates that 65,980 new cases were diagnosed in 2009 and that 19,500 people died of the disease in the same time period. The overall survival rate for NHL varies based on the type and stage of disease, but the overall 5-year survival rate is 65% and the 10-year survival rate is 54%.

There are numerous types of NHL. One of the most common is diffuse large B-cell lymphoma (DLBCL), which accounts for about 33% of NHL cases and is mostly diagnosed in older people. It is a fast-growing lymphoma, but it frequently responds to therapy. About 75% of people treated for DLBCL achieve remission after initial treatment, and about 50% are cured of disease. Follicular lymphoma also arises from B-cells and accounts for about 20% of all lymphomas. It is a more slow-growing cancer, with a 5-year survival rate of around 70%. About a third of these cancers will change into the faster-growing DLBCL. Other less common types of B-cell NHL include chronic lymphocytic leukemia/small lymphocytic lymphoma, mantle cell lymphoma, marginal zone B-cell lymphoma, and mucosa-associated lymphoid tissue (MALT) lymphoma. About 15% of NHL cases arise from T-cells rather than B-cells.  These cancers include precursor T-lymphoblastic lymphoma/leukemia and peripheral T-cell lymphomas.

Most cases of NHL are diagnosed in people over the age of 60 years, and the disease is more common in caucasians. Other risk factors for developing NHL include exposure to some chemicals, prior exposure to other chemotherapy drugs or radiation therapy, immune deficiency, some autoimmune diseases and infection with Epstein-Barr virus (EBV), human immunodeficiency virus (HIV), and Heliobacter pylori.

Treatment for NHL varies greatly based on the type and stage of disease. Common treatments include radiation, which may be used alone to treat early disease (stage I or II) and in combination with chemotherapy to treat more advanced disease; chemotherapy (often multiple drugs used in combination); and immunotherapy with antibodies or interferon.

Multiple Myeloma

Multiple myeloma (MM) is a cancer that arises in plasma cells, which are found in the bone marrow and play an important role in the body’s immune system.  The American Cancer Society estimates that about 20,580 new cases of MM were diagnosed in the United States in 2009, and that 10, 580 people died of the disease over the same time period.  The 5-year survival rate for MM is about 35%.

Plasma cells are the mature form of B-cells, and they produce antibodies that are used to fight infections. When they become cancerous, they form tumors known as plasmacytomas, which are usually found in bone. If multiple plasmacytomas occur throughout the bone, the disease is called multiple myeloma (MM). Overgrowth of plasma cells in the bone marrow due to MM can inhibit the formation of other normal blood cells, which can lead to anemia, bleeding, bruising, and reduced ability to fight infections. MM cells also interfere with normal bone cells, leading to weak bones that are easily fractured.

Risk factors for developing MM include age, race, family history, obesity and environmental factors. MM is most common in people over the age of 65 years, and occurs in almost twice as many African-Americans as white Americans. A person with a parent or sibling who has had MM is four times more likely to develop the disease. Being overweight or obese also increases risk. Workers in certain petroleum-related industries may have an increased risk of MM.

Treatment choices for MM depend on disease stage, and a patient’s age and kidney function. Chemotherapy, often a combination of drugs, may be used to treat MM. Radiation may be used to treat areas of bone that have not responded to chemotherapy. Interferon may be used to prolong remission in patients successfully treated with chemotherapy. Stem cell transplantation following chemotherapy may also be used, especially for younger patients who are otherwise healthy.

Adapted from the Leukemia & Lymphoma Society’s “Disease Information: Facts & Statistics, and the American Cancer Society’s “Detailed Guide: Lymphoma, Non-Hodgkin Type” and “Detailed Guide: Multiple Myeloma”

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