The Target : Leukemia : Important TermsLeukemia
Leukemia is a malignant disease (cancer) that originates in a cell in the marrow
Lymphoma is a general term for a group of cancers that originate in the lymphatic system
Hodgkin lymphoma (also known as Hodgkin's disease) is a specialized form of lymphoma and represents about 12.5 percent of all lymphomas diagnosed each year
Myeloma is a cancer of plasma cells, a type of white blood cell found in many tissues of the body, but mainly in the marrow
Myelodysplastic syndromes are a group of diseases that originate in an early blood-forming cell in the marrow
Leukemia, cancer of the bone marrow and blood, is characterized by the uncontrolled growth of blood cells. There are four main types:
Leukemia represents 2 percent of all the adult cancers and a third of all childhood cancers. In 1998, leukemia will be diagnosed in an estimated 26,500 adults and 2,200 children in the United States.
Fatigue, paleness, weight loss, repeated infections, bruising and nosebleeds
Chemotherapy and bone-marrow transplants
Five-year survival rate:
For children, 80 percent; for adults, 42 percent. During the past 20 years, leukemia death rates have dropped 5.1 percent, largely because of the strides made in treatment.
Chemicals and solvents linked to leukemia
benzene, pesticides, arsenic, chromium, butadiene, dioxin, ethylene oxide, heptachlor, herbicides, hydrazine, mycotoxins, perchloroethylene, polychlorinated biphenyls (PCBs), toluene, tetrachloroethylene, trichloroethylene, trinitrotoluene
Sources: Leukemia Society of America, Agency for Toxic Substances and Disease Registry, Ohio Environmental Protection Agency
Leukemia, Hodgkin and non-Hodgkin lymphoma and myeloma are cancers that originate in the bone marrow or lymphatic tissues. They are considered to be related cancers because they involve the uncontrolled growth of cells with similar functions and origins. The diseases result from an acquired genetic injury to the DNA of a single cell, which becomes abnormal (malignant) and multiplies continuously. The accumulation of malignant cells interferes with the body's production of healthy blood cells and can leave the body unable to protect itself against infection.
An estimated 106,200 people in the United States will be diagnosed with leukemia, lymphoma or myeloma in 2003. New cases of leukemia, Hodgkin and non-Hodgkin lymphoma and myeloma account for 8 percent of the 1,334,100* new cancer cases diagnosed in the United States this year.
Source: Surveillance, Epidemiology and End Results (SEER) Program 1975-2000, National Cancer Institute.
An estimated 670,950 Americans are currently living with leukemia, Hodgkin and non-Hodgkin lymphoma and myeloma.
Leukemia, lymphoma and myeloma will cause the deaths of an estimated 57,500 people in the United States this year. These blood cancers will account for nearly 10.3 percent of the deaths from cancer in 2003 based on the total of 556,500 cancer-related deaths (all sites).
Every nine minutes, another child or adult is expected to die from leukemia, lymphoma or myeloma. This statistic represents 158 people each day - seven people every hour. Leukemias are the leading fatal cancers in young men and women under age 20.
The use of chemotherapy (anti-cancer drugs), usually in combinations of two or more drugs, is largely responsible for the dramatic improvement in managing leukemia and lymphoma. Approximately 50 different drugs are now being used in the treatment of these diseases.
Patients with leukemia, myeloma or lymphoma are usually treated with chemotherapy. Some patients with localized lymphoma may be treated with radiation therapy. Patients with acute lymphocytic leukemia (ALL), with large areas of lymphoma accumulation or with special complications that are amenable to radiation therapy may receive both primary chemotherapy and ancillary radiation therapy.
Blood and Marrow Stem Cell Transplantation
Stem cell transplantation from marrow was introduced approximately 35 years ago and is now standard therapy for selected patients with leukemia, lymphoma and myeloma. There are two major types of stem cell transplants: syngeneic and allogeneic. Syngeneic transplant describes the use of an identical twin as donor. An allogeneic transplant uses blood or marrow stem cells from a normal donor, usually a brother or sister with the same tissue type. If a sibling is not available, a search of the National Marrow Donor Program registry of tissue-typed volunteers could be made for a matched unrelated donor. In special instances, especially in young children, mismatched donors may be used, for example a parent.
Autologous transplantation uses the patient's own marrow stem cells and is technically not transplantation since another person is not the donor. The technique is important, however. The blood or marrow stem cells are collected while the patient is in remission, and it may be treated with chemotherapy agents or monoclonal antibodies to decrease the presence of contaminating tumor cells before being given back. The stem cells are frozen and administered later in the course of the disease if intensive chemotherapy and/or radiotherapy is required for subsequent treatment.
The technique of harvesting stem cells from blood and cord blood has made transplantation available for more patients. Blood and cord blood transplants differ from marrow transplants principally in the source of the cells collected for transplant. Stem cells not only reside in the marrow but also circulate in the blood. Because blood, as well as marrow, is a source of stem cells for transplantation, these cells can be harvested from the blood of a donor, frozen and stored, and later transplanted to the patient. To ensure there will be enough blood stem cells for successful transplantation, donors of blood stem cells require special treatment to mobilize sufficient stem cells from marrow into their blood before cells are harvested.
Stem cells circulate in large numbers in fetal blood also and can be recovered from umbilical cord and placental blood after childbirth. The harvesting, freezing and storing of cord blood has provided another source of stem cells for transplantation, especially for children. The numbers of stem cells in cord blood are often insufficient for the needs of larger adult patients.
Cord blood stem cell transplantation provides an additional donor pool and the opportunity for greater racial diversity in the blood supply because of collection efforts in hospitals where children of underrepresented ethnic backgrounds are born.
"Non-ablative" allogeneic stem cell transplantation is the term applied to a technique of allogeneic transplant that uses lower doses of chemotherapy and/or radiotherapy to prepare the recipient to receive the donor's stem cells. This still experimental approach greatly lessens the early toxicity of transplantation and has extended the age at which recipients with leukemia or lymphoma can have a transplant. It has been made possible by more effective immunosuppressive drugs that are capable of preventing rejection of the donor's cells without full intensity treatment of the patient's immune system. Over time the donor's cells take hold and the patient's leukemia or lymphoma is attacked and suppressed by donor lymphocytes that form from the donor stem cells. This "graft versus leukemia or lymphoma effect" suppresses (cures) the malignancy and is a prolonged (indefinite) form of immunotherapy. In standard stem cell transplantation, ablation of the recipient's blood-cell-forming and immune cells was the price that had to be paid to eradicate the leukemia or lymphoma and permit the donor's cells to be accepted by the temporarily immunodeficient recipient. "Ablation" referred to wiping-out the recipient's cancer and immune system. In non-ablative transplantation, the recipient's blood cell and immune system are preserved, making the procedure far more tolerable.