According to a study published in The Lancet Oncology, development of neutropenia during chemotherapy for non-small cell lung cancer (NSCLC) may indicate chemotherapy drug activity and effectiveness. On the other hand, lack of neutropenia may signal that the patient was given an insufficient dose of chemotherapy.
Lung cancer remains the leading cause of cancer-related mortality in the United States and Europe. NSCLC refers to the type of cell in which the cancer originated. It accounts for approximately 75% to 80% of all lung cancers.
Neutropenia, one of the most common side effects of chemotherapy, occurs when white blood cells (immune cells) are destroyed by chemotherapy, leaving the immune system unable to fight infections. Chemotherapy-induced neutropenia can become a serious condition for several reasons: Many patients who develop neutropenia will require a delay in treatment or a dose reduction, which can prevent them from receiving the greatest benefits of treatment; patients who develop neutropenia may require hospitalization; and even minor infections can become life-threatening.
In the current study, researchers in Italy questioned whether the development of neutropenia is a reflection of the activity (and effectiveness against cancer) of the chemotherapy dose received by an individual. Patients who develop neutropenia also have the greatest response to chemotherapy. These patients are likely to have improved survival.
To evaluate the relationship between neutropenia and survival, the researchers analyzed data from three clinical trials of chemotherapy for NSCLC. Severe neutropenia most commonly developed during the first cycle of chemotherapy. Among patients who completed all six of the planned chemotherapy cycles and those unable to complete all chemotherapy cycles, those who developed neutropenia survived longer than patients who did not. Survival was similar in patients who developed mild neutropenia compared to patients who developed more severe neutropenia.
The researchers conclude that the development of neutropenia in NSCLC may be a sign of the adequacy of the chemotherapy dose. The patients who develop neutropenia appear to be those experiencing the greatest anti-cancer effect of chemotherapy. Conversely, patients who do not develop neutropenia may be receiving a chemotherapy dose that is too low to have optimum effectiveness against cancer.
With the recent introduction of drugs to prevent neutropenia, such as Neulasta® (pegfilgrastim), patients may be able to receive optimal doses of chemotherapy without having to experience neutropenia. Because severe neutropenia commonly occurs during the first cycle of chemotherapy, use of drugs to prevent neutropenia may have the greatest benefit if given before the first cycle of chemotherapy.
Reference: Di Maio M, Gridelli C, Gallo C et al. Chemotherapy-induced neutropenia and treatment efficacy in advanced non-small-cell lung cancer: a pooled analysis of three randomized trials. The Lancet Oncology. 2005;6:669-77.
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