Leukemia, a cancer that begins in blood-forming tissues, frequently leads to anemia. Anemia is a blood disorder defined by a deficiency of healthy red blood cells or hemoglobin, the protein that transports oxygen throughout the body. The connection between these two conditions arises because both involve the bone marrow, the spongy tissue inside bones where all blood cells are produced. Understanding this relationship requires looking at how the uncontrolled growth of cancerous cells disrupts the body’s normal blood production process.
The Underlying Cause of Anemia in Leukemia
The primary mechanism linking leukemia and anemia involves the physical displacement of healthy blood-forming cells within the bone marrow. The bone marrow produces all blood components, including red blood cells, white blood cells, and platelets. In leukemia, abnormal, immature white blood cells, called leukemic blasts, multiply rapidly and uncontrollably.
This rapid growth results in the cancerous cells crowding out the hematopoietic stem cells, which are the precursors for normal red blood cells. Since the healthy stem cells cannot proliferate effectively, the bone marrow cannot produce an adequate number of functional red blood cells. This reduced output directly causes anemia.
Other factors also contribute to the deficiency, including the release of inflammatory cytokines by the cancer, which can suppress the differentiation of red blood cell precursors. The disease process can also impair iron utilization and reduce the production of erythropoietin, a hormone that stimulates red blood cell formation. In acute forms of leukemia, this disruption happens quickly, making anemia an early finding.
Recognizing Symptoms of Anemia
The effect of anemia is reduced oxygen-carrying capacity in the blood, which manifests in several noticeable symptoms. The most common symptom is profound fatigue and generalized weakness that is not relieved by rest. This occurs because the body’s tissues and organs are starved of the necessary oxygen to produce energy.
A person with anemia may also experience shortness of breath, particularly during physical activity, as the body attempts to compensate for low oxygen levels. Other signs include lightheadedness or dizziness, often felt when rising quickly, and a noticeably pale appearance to the skin and mucous membranes (pallor). The heart may also respond to the lack of oxygen by beating faster, leading to a rapid or irregular heart rate.
Addressing Anemia During Leukemia Treatment
Managing anemia is an important part of supportive care for patients undergoing leukemia treatment. The most immediate intervention is a red blood cell transfusion, which directly replaces the deficient cells and quickly raises the patient’s hemoglobin level. Transfusions are typically given to patients who are symptomatic or whose hemoglobin levels drop below a certain threshold, such as 7 or 8 grams per deciliter.
In less acute situations, or for anemia related to chemotherapy, doctors may use Erythropoiesis-Stimulating Agents (ESAs). These medications, such as epoetin alfa or darbepoetin alfa, mimic the natural hormone erythropoietin and stimulate the bone marrow to increase red blood cell production. The goal of ESA therapy is to reduce the need for blood transfusions and improve the patient’s quality of life.
The long-term solution for anemia caused by leukemia is the successful treatment of the underlying cancer. Chemotherapy, targeted therapy, or a stem cell transplant works to eliminate the leukemic blasts, restoring the bone marrow’s ability to produce healthy blood cells. As the cancerous cells recede, the normal hematopoietic stem cells regain the space and resources needed to generate a functional supply of red blood cells.