Variables Predictive of Development of Anemia in Breast Cancer Patients
According to a recent article published in The Lancet Oncology, pre-treatment hemoglobin and platelet levels, an age of 65 years or older, type of chemotherapy and number of chemotherapy cycles all predict the risk of developing anemia for breast cancer patients undergoing chemotherapy. Patients at a higher risk may benefit from more aggressive prophylactic measures to protect against the development of anemia.
Anemia is a condition in which circulating red blood cells (RBCs) fall below normal levels. Red blood cells (RBCs) are responsible for delivering oxygen to tissues throughout the entire body. Bone marrow (spongy material inside large bones) is stimulated to produce RBCs by a chemical substance called erythropoietin, which is secreted by the kidneys. Each RBC contains many molecules of hemoglobin, a protein-iron complex responsible for delivering oxygen to the cells and carbon dioxide to the lungs.
Erythropoietin can be manufactured outside the body and administered to patients. Recombinant human erythropoietin, or epoetin alfa, is comprised of manufactured erythropoietin and is commonly used for cancer patients receiving treatment. Epoetin alfa has been shown to reduce the severity of anemia and to reduce symptoms of fatigue by stimulating the bone marrow to produce more RBCs.
The two forms of epoetin alfa most often utilized for the treatment of anemia in the United States are Aranesp® (darbepoetin alfa) and Procrit® (epoetin alfa). Aranesp, which requires less frequent dosing than Procrit, has been approved by the FDA for the treatment of anemia caused by chemotherapy in non-myeloid cancers (cancers that do not originate in blood cells).
Recent research has focused on establishing risk assessment protocols, in which patients are assessed according to specified variables to determine if they are at a high risk of developing anemia. If so, they may undergo preventive treatment with an erythropoeitic agent to reduce their risk of developing anemia and its associated side effects.
Researchers from Canada recently reviewed data from medical records of patients with breast cancer who underwent chemotherapy in an attempt to determine which patient or cancer characteristics may be associated with an increased risk of developing anemia. This study included 331 patients with early breast cancer (cancer had not spread to distant sites in the body) who underwent chemotherapy for their disease.
Analysis of results indicated the following variables are associated with an increased risk of the development of anemia:
• Lower hemoglobin level prior to treatment
• Lower platelet count prior to treatment (200 x 109 or fewer)
• Age 65 years or older
• No prophylactic antibiotics
• Treatment with the chemotherapy combinations referred to as FEC, CEF, CAF, FAC, FEC100, or AC-T
• Fewer delivered chemotherapy cycles
The researchers concluded that variables have now been identified that place breast cancer patients at a higher risk of developing anemia. Patients who are considered high-risk for developing anemia may benefit from a more proactive or preventive approach with the agents Aranesp or Procrit.
Patients with breast cancer who are to undergo chemotherapy may wish to speak with their physician about their individual risks of developing anemia, and potential strategy to reduce these risks.
Reference: Dranitsaris G, Clemons M, Verma S, Lau C, Vincent M. Chemotherapy-induced anaemia during adjuvant treatment for breast cancer: development of a prediction model. The Lancet Oncology. Early online publication. October 10, 2005. DOI:10.1016/S1470-2045(05)70394-6.