Chemotherapy-induced neutropenia

Chemotherapy-induced neutropenia is a condition characterized by abnormally low blood levels of infection-fighting neutrophils, a specific kind of white blood cell.cite journal |author=Lyman GH |title=Risks and consequences of chemotherapy-induced neutropenia |journal=Clin Cornerstone |volume=8 Suppl 5 |issue= |pages=S12–8 |year=2006 |pmid=17379159 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S1098-3597(06)80054-2] The most common reason that cancer patients experience neutropenia is as a side effect of chemotherapy. Chemotherapy involves the use of drugs to destroy cancer cells. Chemotherapy works by destroying cells that grow rapidly, a characteristic of cancer cells. Unfortunately, chemotherapy also affects normal cells that grow rapidly, such as blood cells in the bone marrow, cells in the hair follicles, or cells in the mouth and intestines. Chemotherapy-induced neutropenia typically occurs 3–7 days following administration of chemotherapy and continues for several days before neutrophil levels return to normal. The type and dose of chemotherapy affects how low the neutrophil count drops and how long it will take to recover.

Chemotherapy-induced neutropenia is important because it may: Increase a patients risk of life-threatening infection and ordisrupt delivery of cancer treatment, resulting in a change to the planned dose and time.The fewer the neutrophils in the blood and the longer patientsremain without enough neutrophils, the more susceptible patients are to developing a bacterial or fungal infection. Neutrophils are a major component of antibacterial defense mechanisms. As the neutrophil count falls below 1.0, 0.5, and 0.1 x 109/L, the frequency of life-threatening infection rises steeply from 10% to 19% and 28%, respectively. If patients develop a fever during neutropenia they may require treatment with intravenous antibiotics and admission to the hospital until the number of neutrophils in the blood returns to sufficient levels to fight the infection.

Another reason neutropenia is important is that, in some cases, it can be severe enough that it can cause the chemotherapy treatment to be delayed or dose reduced, which reduces some patients’ chance for cure. When patients are treated with chemotherapy, it is for the purpose of destroying cancer cells in order to reduce symptoms from your cancer, prolong your survival or increase your chance of cure. The dose and time schedule of chemotherapy drugs administered have been scientifically determined to produce the best chance of survival or cure. If patients develop neutropenia, doctors may have to delay your treatment or reduce the doses of chemotherapy until the neutrophil counts have recovered. Clinical studies have shown that, for certain cancers, reducing the dose of chemotherapy or lengthening the time between treatments lowers cure rates compared to full-dose, on-time treatment. There are however strategies for the prevention of chemotherapy-induced neutropenia that have been proven to reduce the incidence of fever, infection, admission to the hospital and allow patients to receive treatment on schedule.

Risk factors

Who is at a higher risk for chemotherapy-induced neutropenia?Patients receiving chemotherapy that decreases the number of white blood cellsPatients who already have a low white blood cell count, or who have previously received chemotherapy or radiation treatmentPatients age 70 and older who may be at risk of more severe infection and longer hospitalizationsPatients with other conditions affecting their immune system

Prevention

Chemotherapy-induced neutropenia can be prevented in most patients with the use of white blood cell growth factors. Blood cell growth factors are naturally occurring substances called cytokines that regulate certain critical functions in the body. They are responsible for stimulating cells in the bone marrow to produce more blood cells. The white blood cell growth factors approved by the U.S. Food and Drug Administration for the prevention of chemotherapy-induced neutropenia are Neupogen (filgrastim) and Neulasta (pegfilgrastim).

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