Falling Blood Counts in Cancer Patients: What Is Chemotherapy-Induced Anemia?

When a person develops anemia as a side effect of chemotherapy, the condition is called chemotherapy-induced anemia (CIA) . It may cause fatigue, dizziness and an increased heart rate, among other symptoms .

Chemotherapy is a drug treatment used for many cancers to stop rapidly dividing cancer cells from multiplying and spreading. However, chemicals in chemotherapy drugs can also damage other rapidly dividing cells, causing side effects such as anemia.

Anemia occurs when the body does not produce enough healthy red blood cells or hemoglobin , which are needed to transport oxygen to the body's cells.

Why Does Chemotherapy-Induced Anemia Occur?

Some chemicals in chemotherapy drugs suppress erythropoiesis, the process by which the body produces new red blood cells. Chemotherapy also targets other rapidly dividing cells, such as erythroid precursor cells. These are erythrocytes (red blood cells) or their stem cells. Chemotherapy drugs can trigger red blood cell death. These two effects can cause chemotherapy-induced anemia. However, the most common cause of anemia is iron deficiency, and iron deficiency anemia is different from chemotherapy-induced anemia.

Symptoms of Chemotherapy-Induced Anemia

Symptoms of chemotherapy-induced anemia may include:

• Fatigue
• Drowsiness
• Shortness of breath
• Dizziness
• Increased heart rate
• Loss of appetite
• Depression

However, these symptoms can also arise from other health problems. Anyone experiencing them should consult a specialist to be on the safe side.

How Is Chemotherapy-Induced Anemia Diagnosed?

To diagnose chemotherapy-induced anemia (CIA), a doctor will usually:

• Perform a physical examination
• Ask about symptoms
• Review the full medical history, including information about chemotherapy and any other treatments the person is currently receiving

The doctor may then request various tests to confirm anemia and rule out other possible causes. These may include a hemogram (complete blood count) , which provides information about blood components that may indicate anemia. Specialists may also request a bone marrow test to see whether the marrow is healthy and producing normal amounts of blood cells.

How Does HGB in a Complete Blood Count Indicate Anemia?

Hemoglobin (HGB)

Hemoglobin is a protein in red blood cells responsible for carrying oxygen to the body's tissues. Measuring hemoglobin levels in a complete blood count can reveal signs of anemia. Normal values are:

• For men: 13.8 to 17.2 g/dL
• For women: 12.1 to 15.1 g/dL

Anemia is diagnosed when hemoglobin levels are below these normal ranges. Low hemoglobin levels indicate that red blood cells cannot transport oxygen effectively, which can cause fatigue, shortness of breath, palpitations and tiring easily.

White Blood Cells (WBC)

White blood cells protect the body against infections and disease. In a complete blood count, the WBC count indicates the body's current infection or inflammation status. The normal WBC count ranges from 4,000-11,000 cells/mcL. A high WBC count may indicate that the body is fighting an infection or that inflammation is present. A low WBC count, known as leukopenia , means the body's defenses against infection are weaker. Chemotherapy is generally not given when the WBC count is below 3 thousand cells/mcL, and treatment may be postponed to allow the bone marrow to recover.

Platelets (PLT)

Platelets are small cells that help blood clot. In a complete blood count, the PLT count indicates the blood's clotting ability. A normal PLT count ranges from 150,000-450,000 cells/mcL. A low PLT count may indicate an increased risk of bleeding, while a high count may indicate an increased risk of thrombosis. Chemotherapy is generally not given when the PLT count is below 100 thousand cells/mcL, and treatment may be postponed to allow the bone marrow to recover.

Why Are Blood Transfusions Given to Cancer Patients?

Blood transfusion is an option for treating CIA. This treatment involves transfusing red blood cells from a donor. It may benefit people with severe, symptomatic anemia or bleeding; red blood cell transfusion is generally considered when hemoglobin is below 9 g/dL. Before a transfusion, however, specialists consider many factors, including the intensity of ongoing chemotherapy and the person's overall health.

How Can Low Blood Counts Be Increased During Chemotherapy?

Drug treatments are another option for CIA. Specialists recommend medications that stimulate red blood cell production. Known as erythropoietin-stimulating agents (ESAs), these are recombinant versions of the hormone erythropoietin. However, a 2020 study showed that ESA use carries some risks and that they should not be used in certain situations. ESAs stimulate the division and differentiation of erythroid progenitor cells. Examples include:

• Epoetin
• Darbepoetin
• Methoxy polyethylene glycol-epoetin beta

The study states that ESAs should not be used in people with CIA because they increase the risk of thromboembolic events. It may also take 4-6 weeks for a person with CIA to benefit from ESA treatment, and one third of these patients do not respond to ESA therapy alone.

Can Radiotherapy or Immunotherapy Also Cause Anemia?

Radiotherapy and immunotherapy are other cancer treatments that can cause anemia, although not as intensely as chemotherapy. These treatments can damage healthy cells while targeting cancer cells, causing side effects such as anemia. However, more research is needed into whether these treatments cause anemia.

How Long Does Chemotherapy-Induced Anemia Last?

The duration of CIA can vary depending on the type and dose of chemotherapy drugs used and the person's overall health. A person with CIA may notice an improvement in symptoms after completing chemotherapy. This recovery may take 2-4 weeks.

What Are the Potential Complications of Chemotherapy-Induced Anemia?

Anemia can affect quality of life and shorten survival in people with cancer. A person may feel more tired because their cells are not receiving enough oxygen. The heart may work harder, which can cause heart problems or worsen existing ones. Severe anemia can affect or delay cancer treatment. The chemotherapy dose may need to be reduced, potentially making cancer treatment less effective. Doctors will manage anemia to reduce the risk of possible complications.

Chemotherapy-Induced Anemia in Summary

Chemotherapy-induced anemia is a side effect that can occur when chemotherapy drugs damage the bone marrow cells that produce red blood cells. Symptoms of CIA include fatigue, shortness of breath and dizziness. Doctors can diagnose CIA after a physical examination, blood tests and bone marrow aspiration or biopsy. Treatment may include blood transfusions and drugs that stimulate red blood cell production. How long CIA lasts will vary with the type and dose of chemotherapy drugs used and the person's overall health.