What is Lymphoma?
Lymphoma is a type of cancer that develops in the lymphatic system. The lymphatic system is part of the body's immune system that helps the body fight disease and infection. The lymphatic system includes a network of vessels that carries lymph, a fluid that contains infection-fighting cells called lymphocytes. Among this network of vessels are small organs called lymph nodes, which are spread along the body. Other parts of the lymphatic system include the spleen, thymus, tonsils, bone marrow, intestines, and skin.In non-Hodgkin's lymphoma, as well as in Hodgkin's disease, the lymphatic system becomes abnormal. The cells divide and grow without any order or control, eventually causing lymphoma. It can happen in any part of the body. Lymphoma accounts for about 5 percent of all cases of cancer in this country and is one of the few malignancies in the United States that is showing an increase in incidence.
What is non-Hodgkin's lymphoma?
There are two main types of lymphocytes: B lymphocytes (B-cells) and T lymphocytes (T-cells). Normal, healthy B-cells produce antibodies that guide the immune system in fighting and killing harmful bacteria. Normal, healthy T-cells recognize and destroy virus-infected or cancer cells. Non-Hodgkin's lymphoma (NHL) occurs with the malignant (cancerous) growth of B or T-cells. There are over 29 different types of NHL, each differentiated by the type of cancer cell. When lymphoma occurs, some of the cells in the lymphatic system grow abnormally and out of control. Eventually, they may form a tumor that continues to grow as the cancerous cells reproduce. If all the cells are the same, they are called malignant or cancerous because they will continue to grow and eventually harm the body's systems. Because there is lymph tissue throughout the body, the cancer cells may spread to other organs or even into the bone marrow.
What is Hodgkin's disease?
The primary difference between Hodgkin's disease and non-Hodgkin's lymphoma is the presence of a specific abnormal cell: Reed-Sternberg cells. These cells, however, are not unique to Hodgkin's disease and on rare occasions can be encountered in non-Hodgkin's lymphomas. These large, malignant cells are found in diseased tissues and are thought to be a type of malignant B lymphocyte. As the number of Reed-Sternberg cells increases, the disease advances, destroying healthy normal cells. External beam radiation typically is used to treat Hodgkin's when the disease is localized to one area of the body or is so large in mass that even chemotherapy cannot completely kill all the cancerous cells. In this treatment, a concentrated beam of high-energy rays is delivered to the involved body part. The radiation slows cell growth or destroys the cells altogether.
What is multiple myeloma?
Multiple myeloma is a type of cancer that affects the bone marrow. Multiple myeloma is part of a spectrum of diseases called plasma cell dyscrasia. In multiple myeloma, plasma cells lose their ability to respond to controlling signals from a hierarchy of immune cells. When myeloma cells become independent of the immune system, they divide into numerous cells that the body does not need and form large amounts of abnormal proteins that damage bone, bone marrow or other organs of the body. As myeloma cells continue to divide out of control, the space within the bone marrow constricts, impairing the production and function of red blood cells, white blood cells, and platelets. When these normal antibodies are impaired, the body loses resistance to infection, and may develop other diseases such as pneumonia or kidney infections. Myeloma cells physically displace bone structure and secrete a chemical that destroys bone.
What treatment is available at M. D. Anderson - Orlando?
Lymphoma/Myeloma Technologies used in the treatment of these blood disorders at M. D. Anderson - Orlando include radiation therapy with external beam or radiolabel antibodies such as Zevalin, biotherapy, chemotherapy, and bone marrow transplantation.
Radiation can also be combined with a monoclonal antibody (MAB), which is a protein made from a single parent cell, to form radiolabel antibodies. In this case, the MABs contain a radioactive substance such as radioactive iodine that targets and destroys the cancer cells. With this form of therapy, the tumor cells receive a large amount of radiation and normal tissue is spared. This treatment is generally used for patients whose NHL has either not responded to chemotherapy or has relapsed.
Radioimmunotherapy is a promising new area of cancer treatment that combines the targeting power of monoclonal antibodies with the cell-damaging ability of localized radiation. Radioimmunotherapies like Zevalin are made by linking monoclonal antibodies - engineered in a laboratory to recognize and attach to substances on the surface of certain cells - to radioactive isotopes. When infused into a patient, these radiation-carrying antibodies circulate in the body until they locate and bind to the surface of specific cells, and then deliver their cytotoxic radiation directly to the cancerous cells.
Biotherapy using the body's immune system to fight cancer) is developed by using either vaccines or antibodies against specific markers on the cancer cells. Generally, it is not associated with the traditional side effects of chemotherapy.Bone marrow transplantation may be an option in cases when lymphoma becomes resistant to initial treatment or in cases where it has recurred and only if there is response to salvage therapy. Very high doses of chemotherapy may then be used to treat the cancer. Because the high doses of chemotherapy can destroy a patient's bone marrow, marrow is taken from the patient before treatment. Marrow is then frozen, and the patient is given high-dose chemotherapy with or without radiation therapy to treat the cancer. Marrow that was taken out is then thawed and given back through a needle in a vein to replace marrow that was destroyed. In addition, a lower dose of intense chemotherapy is now being tested where the patient does not develop as much toxicity. When cells of the patient cannot be collected, a suitable donor marrow is searched. In recent years, a new method has been devised whereby particular cells that are collected from the marrow (the stem cells) can now be collected directly from the blood of the patient (or donor).
Zevalin is a monoclonal antibody (MAB or MOAB) for B-cell lymphomas - the first to be approved for human use by the U.S. Food and Drug Administration. Monoclonal antibodies work on cancer cells in the same way natural antibodies work, by identifying and binding to the target cells. They then alert other cells in the immune system to the presence of the cancer cells. MABs are specific for a particular antigen - one designed for a B-cell lymphoma will not work on cells for ovarian cancer cells, for example.
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