The human body is made up of red and white blood cells. Red blood cells carry oxygen to the lungs and different parts of the body while white blood cells protect the body from infection. Neutrophils, one common group of white blood cell produced in the bone marrow, divide and multiply quickly just like cancer cells. Since chemotherapy drugs aim for cancer cells with a high rate of reproduction, many of these neutrophils are also destroyed during treatment, resulting in neutropenia. Neutropenia is defined as a sharp reduction of neutrophils.
Most infections occur in the lungs, mouth, throat, sinuses and skin.
The normal body contains between 2500 and 6000 cells per cubic millimeter. If a patient's ANC is 1000 or less, he or she is considered to be neutropenic. A patient with ANC less than 500 cells per cubic millimeters is considered a severe neutropenic at great risk of developing infections. Most patients with neutropenia develop fever and are treated with antibiotics. Additionally, several new drugs called granulocyte colony stimulating factors may stimulate the growth of neutrophils.