Many patients develop anemia as a result of chemotherapy and this causes them to become fatigued. Anemia occurs when the blood has too little hemoglobin, the part of the red blood cell (RBC) that carries the oxygen needed by your body. Doctors often define anemia as a blood hemoglobin (Hb) level of less than 12 g/dL, but many people will not feel much different until the hemoglobin level falls below 11 g/dL.
Symptoms of anemia will begin to appear as the hemoglobin decreases. These symptoms can include shortness of breath, difficulty breathing on exertion, and fatigue.
These symptoms occur because the body tissues are getting enough oxygen. Anemia can be caused by a number of different factors:
lack of specific vitamins or minerals in the diet
major organ dysfunction (including severe heart, lung, kidney, or liver disease)
destruction of the RBCs
hereditary disorders, such as sickle cell disease
a combination of these factors
Some of these causes may have nothing to do with your cancer. If anemia is the cause of the fatigue, by treating it, the level of fatigue may decrease.
Anemia is diagnosed with a blood test called a complete blood count or CBC. A careful medical history, physical exam, other blood tests such as blood iron and vitamin levels, and a bone marrow test may also help to find the cause of the anemia.
The goal of treatment for anemia is to treat the cause of the anemia and to improve the hemoglobin level so that the symptoms will go away. Examples of treatments for anemia include eating nutrient-rich foods, taking iron and folic acid supplements, and stopping any bleeding. A transfusion of red blood cells may be given to treat anemia, especially in cases where the hemoglobin level needs to be raised quickly.
Another way to treat anemia is by using drugs such as epoetin (e-poy-ee-tin) or darbepoetin (dar-beh-poy-ee-tin). Erythropoeitin (e-rith-ro-poy-ee-tin) is a natural substance that is normally produced by the kidneys. This substance helps the body make its own new red blood cells. Cancer treatment can impair the ability of the kidneys to make erythropoietin, causing decreased numbers of red blood cells and anemia. Epoetin and darbepoetin can be used to work in place of the body's natural erythropoietin and help the bone marrow make red blood cells. However, several studies have found a higher chance of serious or life-threatening side effects with the use of these drugs. They should only be used for patients on active treatment and after careful consideration of their risks and benefits.
Still, studies have shown that the use of these drugs in patients getting chemotherapy resulted in an increase in their hemoglobin levels and a reduced need for blood transfusions. Although the evidence was not quite as strong, an equally important finding in these studies was the effect of anemia on the patients' quality of life. Patients with anemia had a lower quality of life than they had when anemia was not present. When the anemia was corrected, the patient's quality of life often improved. Some studies have now begun looking at whether or not correcting anemia during cancer treatment can help people to live longer. More research is needed to find out if the use of erythropoietin is effective for long-term cancer survival.