Leukemia

Each member of our clinical medical assistant class was required to choose a cancer and discuss it in a presentation. I chose leukemia, and here is what I found.

Leukemia Defined

Leukemia is a cancer of the bone marrow, blood, and the lymphatic system in general (a drainage system that removes excess fluid from the space between the body’s tissues).

There are four major forms of leukemia, named for the type of cell affected (myeloid or lymphoid cell), and for the speed at which it develops (1).

1. acute myeloid leukemia (AML)*

2. acute lymphoblastic leukemia

3. chronic myeloid leukemia

4. chronic lymphocytic leukemia

Founders

Dr. John Hughes Bennett is credited as first diagnosing leukemia as a blood disease in 1845, although Alfred Velpeau (1827) and Alfred Donne (1844) described the disease before him. Bennett called the disease leucocythaemia.

Description

Leukemia occurs when the DNA inside normal blood cells mutates, causing the cells to develop and divide more quickly, and to live longer, than normal blood cells. The resulting overabundance of these abnormal cells, however, cannot fight infection as normal white blood cells do. In addition, because so many of these abnormal cells are produced, the bone marrow cannot produce healthy blood cells as efficiently (1).

Symptoms

*Since the bone marrow produces ineffective white blood cells, the body cannot adequately fight disease, leading to increased frequency of fever and infection.

*Because of the bone marrow’s inability to produce red blood cells, responsible for carrying oxygen throughout the body, a person with leukemia can develop anemia (low red blood cell count) and fatigue.

*Because the bone marrow cannot produce adequate platelets to clot the blood, people with leukemia may experience frequent and prolonged bleeding (2).

Additional symptoms include paleness, weight loss; lack of appetite; enlarged lymph nodes, spleen, or liver; petechiae (small red spots appear on the skin); bone pain; and excessive sweating.

Risk Factors

Although most people with these risk factors do not develop leukemia, the following risk factors can be generally ascribed to one or more leukemia type: prior cancer treatment with chemotherapy (AML) or radiation (AML, ALL, CML); specific genetic disorders, including Down Syndrome (AML); exposure to benzene (found in gasoline and cigarette smoke) (AML); blood disorders; history of leukemia in the family

Diagnosis and Mortality

According to the American Cancer Society, it was estimated that 44,600 people would be diagnosed with leukemia in 2011, and that 21,780 people would die. Like many other cancers, men were more likely to die from leukemia compared to women; and for 2011, more people were estimated to die from leukemia in California than in any other state (over ten percent of the total). Deaths from leukemia, however, have fallen since at least 2003 (3).*

Treatment

*The most common treatment for leukemia is chemotherapy, which uses chemicals (via pill or injection) in the form of imatinib, nilotinib, and dasatinib, to kill leukemia cells in CML (and some ALL) patients. Imatinib, for example, stops the functioning of a protein in chronic myeloid leukemia cells.

*Biological therapy is used to help your body identify and destroy leukemia cells, while radiation therapy (via x-rays and other forms) is intended to damage leukemia cells to stop their growth.

*Stem cell treatment can replace diseased bone marrow with healthy bone marrow. Before this procedure, the body’s existing bone marrow is destroyed with chemotherapy or radiation therapy. The bone marrow is then injected with blood-producing stem cells (1, 3).

*According to a study presented by the American Association for Cancer Research, blacks and Hispanics were also more likely to die from acute leukemia compared to whites (17 percent and 12 percent higher, respectively). At face value, the raw numbers seemed to indicate otherwise:

Out of the 2,299 black patients involved in the study, 1,953 died inside a five-year period (about 85%).

Of the 4,428 Hispanic patients involved, 3,322 died in that period (about 75%)

Of the 22,035 white patients in the study, 18,980 died (about 86%).

It is possible that fewer whites than blacks and Hispanics died in the second half of the ten-year study, which would explain the apparent contradiction. The lead physician, Dr. Manali I Patel, explained the findings, saying, "like all disparities in cancer there could be any combination of influences; however we believe that socioeconomic factors and access to care may be playing an important role." (4, 5) It is interesting to note the prediction that more men would be diagnosed with new cases of cancer-- including lekemia-- and more men would die of cancer, compared to women (4).

1. “Leukemia.”  The Mayo Clinic. The Mayo Foundation for Medical Education and Research. Scottsdale, AZ: 2011. Web. 29 December 2011.

2. “Childhood Cancer: Leukemia.” KidsHealth. The Nemours Foundation. Wilmington, DE: 2011. Web. 29 December 2011.

3. “Leukemia.” The Leukemia and Lymphoma Society. White Plains, NY: 18 March 2011. Web. 29 December 2011.

4. “Cancer Facts and Figures 2011.” American Cancer Society. Atlanta, GA: 2011. Web. 30 December 2011; “Death Rate Higher in Minorities with Acute Leukemia.” American Association for Cancer Research. Philadelphia, PA: 19 September 2011. Web. 30 December 2011.

5. "Death Rate Higher in Minorities with Acute Leukemia." AAAS, The Science Society. 19 September 2011. Web. 15 January 2012.