Can chemotherapy (chemo) cause anemia?

Chemotherapy-Induced Anemia: Causes and Mechanisms

Yes, chemotherapy can definitely cause anemia through multiple mechanisms, primarily by directly suppressing bone marrow production of red blood cells. 1

Mechanisms of Chemotherapy-Induced Anemia

• Chemotherapeutic agents directly impair hematopoiesis in the bone marrow, including synthesis of red blood cell precursors 1
• Nephrotoxic effects of certain agents (particularly platinum-containing agents) can lead to decreased renal production of erythropoietin 1
• The myelosuppressive effects accumulate over repeated cycles of therapy, with anemia rates increasing from 19.5% in cycle 1 to 46.7% by cycle 5 1
• Cancer itself can contribute to anemia through inflammatory cytokines that lead to iron sequestration and decreased red blood cell production 1

High-Risk Chemotherapy Regimens

• Platinum-based regimens (used in lung, ovarian, and head and neck cancers) are particularly associated with anemia due to combined bone marrow and kidney toxicity 1
• Patients with lung cancer and gynecologic malignancies have a very high incidence of chemotherapy-induced anemia 1
• More intensive chemotherapy regimens may pose a greater risk for developing anemia 1
• Administration of high-risk regimens (those with ≥20% risk of anemia in pivotal trials) is an independent predictive factor for severe anemia 2

Clinical Presentation and Evaluation

• Anemia should be evaluated when hemoglobin levels fall below 11 g/dL or decrease by 2 g/dL or more from baseline 1
• Common symptoms include fatigue, syncope, exercise dyspnea, headache, vertigo, and chest pain 1
• Initial assessment should include CBC with indices and review of peripheral blood smear 1
• Reticulocyte index helps distinguish between decreased production versus increased destruction/loss of red blood cells 1
• Iron studies (serum iron, TIBC, ferritin) should be performed to rule out absolute iron deficiency 1

Risk Factors for Severe Chemotherapy-Induced Anemia

• Low baseline hemoglobin and hematocrit levels 2
• BMI less than 23 kg/m² 2
• High haptoglobin and ferritin levels 2
• Multiple cycles of chemotherapy 1
• Pre-existing renal disease 3

Management Considerations

• Treatment decisions should consider the degree of anemia, presence of symptoms, and comorbidities 1
• For asymptomatic patients without significant comorbidities, observation and periodic reevaluation may be appropriate 1
• For symptomatic patients or those with comorbidities, red blood cell transfusions should be considered 1
• Erythropoiesis-stimulating agents (ESAs) may be considered for specific patients but carry risks including increased mortality, myocardial infarction, stroke, and tumor progression 4
• Intravenous iron supplementation may enhance response to ESAs in patients with functional iron deficiency 1

Monitoring and Prevention

• Monitor hemoglobin weekly after initiation of therapy and after each dose adjustment until levels stabilize 4
• Consider the nadir hemoglobin level (approximately 2 weeks after chemotherapy, but can vary) when evaluating risk 1
• Evaluate iron status in all patients before and during treatment 4
• Administer supplemental iron when serum ferritin is less than 100 mcg/L or when serum transferrin saturation is less than 20% 4

Chemotherapy-induced anemia is a common but serious complication that impacts quality of life and potentially treatment outcomes. Understanding the mechanisms and risk factors can help guide appropriate monitoring and intervention strategies.