It is estimated that 47,150 men and women (26,830 men and 20,320 women) will be diagnosed with, and 23,540 men and women will die of, leukemia this year.
Leukemia is a cancer of the blood that has many forms. Our bone marrow produces red blood cells, platelets and white blood cells. Our platelets are important for clotting, our red blood cells for carrying oxygen and our white blood cells for fighting off infection. The white blood cells can be divided into lymphocytes and non-lymphocytes (myeloid white blood cells). The lymphocytes once they leave the bone marrow are the white blood cells most frequently found in the lymphatic system and lymph nodes while the non-lymphocytic are the white blood cells mostly found in the blood.
Of course, one may find both types of cells in the lymphatic and blood systems. The myeloid type of white blood cells include neutrophils, the most common type of white blood cell. Leukemia can be divided into chronic and acute leukemia. Leukemia generally involves the uncontrolled growth of a subtype our white blood cells with the subtype in part determining what type of leukemia it is. The white blood cells are the most frequent type of cells that undergo uncontrolled growth in the bone marrow hence the name leukemia, which means "white blood."
When the particular type of white blood cell begins to grow rapidly and uncontrolled two things happen: 1, the white cells produced are immature, and 2, they crowd out the growth of other types of blood cells. Thus, the white blood cells being immature do not fight infection and they minimize the growth of red blood cells causing anemia and fatigue. The number of platelets also decreases causing bleeding. Hence, we can now explain the cause of the symptoms of most leukemias: nose bleeds, bruising, fatigue and infections.
Chronic leukemia is a milder disease than acute leukemia and a person may have chronic leukemia for many, many years. Chronic leukemia may be divided into chronic myeloid leukemia and chronic lymphocytic leukemia, which have five-year survival rates of greater than 90 percent and 78 percent, respectively.
Chronic myeloid leukemia accounts for about 15 percent of all leukemias, with the average patient being 66 years old when diagnosed. Chronic lymphocytic leukemia represents about 30 percent of all the leukemias, and those with this disease have a median age of 72.
The chronic leukemias tend to cause mild clinical signs and are frequently diagnosed by the physician when the patient is at his office for other routine matters. Indeed, some individuals with chronic leukemia are not initially treated, as the disease is so mild at the outset. These individuals are just monitored until the disease progresses to the point where chemotherapy might be useful.
Some people will survive chronic leukemia, while others will be unfortunate and see the chronic leukemia transform into a type of acute leukemia, which may be fatal. Acute leukemia presents more severe symptoms than chronic leukemia and may also cause brain hemorrhaging or infarctions, and organ damage due to the overwhelming presence of white blood cells that make the blood very thick - yet incapable of preventing bleeds.
In an analogous fashion to chronic leukemia, acute leukemia can be divided into acute myeloid leukemia and acute lymphocytic leukemia. Acute myeloid leukemia is a disease of older adults, while 60 percent of acute lymphocytic leukemia cases occur in children under 5. It is acute lymphocytic leukemia that affects our children.
The five-year survival rate for those with acute myeloid leukemia is about 22 percent, while the five-year survival for those with acute lymphocytic leukemia is about 63 percent.
Like all cancers, genetic and chromosomal damage causes leukemia. Some individuals have hereditary genetic damage that increases their risk for leukemia while others increase their risk through their environment. Among the environmental risk factors for leukemia development are hair dyes, smoking, exposure to gasoline and similar oils, radiation and chemotherapy treatment for other cancers.
The good news is that there has been much progress in treating leukemia. There are many new drugs that are under development that target specific metabolic pathways within the white blood cells limiting their proliferation rate and at times killing the cell. These new medications tend to have few side effects. When used with chemotherapy, more and more patients are being effectively cured.
By this, I mean the leukemia isn't necessarily eliminated, but is controlled to such a degree that a person will not die from it and will live a complete life.
- Dr. Joseph De Soto, M.D., Ph.D., F.A.I.C. a professor of medicine, obtained his B.S. degree at La Sierra University and attended graduate school at Yale University. He then obtained his M.D. and Ph.D. at Howard University and did his postgraduate training at the National Institutes of Health. He is currently director of Research and Translational Medicine at Bethel University. Oncmed_research@hot mail.com.