Radiosensitizer May Benefit Head and Neck Cancer Patients
According to a study published in the journal The Lancet Oncology, head and neck cancer patients with low oxygen levels in their cancer cells have a better response to radiation therapy if they also receive a radiosensitizer (a drug that makes cancer cells more sensitive to radiation).
Approximately 40,000 people in the United States are diagnosed with head and neck cancer every year. Cancers of the head and neck include cancers of the nasal cavity and sinuses, mouth, and throat. According to the American Cancer Society, 11,000 people died from head and neck cancer in 2004. Standard treatment for head and neck cancer is largely determined by the stage (extent to which the cancer has spread) and by the specific locations within the head or neck area where the cancer has spread.
Among head and neck cancer patients receiving radiation therapy, the oxygen level in cancer cells influences the success of treatment. Radiation therapy is less successful when cancer cells have low oxygen levels. Unfortunately, many cancers, including head and neck cancers, tend to be hypoxic (lacking in oxygen). In order to overcome this problem, researchers are evaluating drugs that mimic oxygen in cancer cells. At this time, the US Food and Drug Administration (FDA) has not approved the use of these drugs, but researchers in Denmark have reported that use of one such drug, nimorazole, improves response to radiation therapy in head and neck cancer patients.
Given the apparent benefit of nimorazole among head and neck cancer patients treated with radiation therapy, the Danish researchers assessed whether certain subgroups of patients were more likely to benefit from nimorazole than others.
Specifically, they were interested in whether patients with the lowest oxygen levels in their cancer cells would benefit the most from treatment with nimorazole. Among 320 head and neck cancer patients, the researchers estimated the oxygen level of cancer cells by measuring a protein in the blood called osteopontin; high levels of osteopontin suggest low levels of oxygen in cancer cells.
Among patients with the highest levels of osteopontin (and presumably the lowest oxygen level in cancer cells), those treated with nimorazole had a better response to radiation therapy. Among patients with low or intermediate levels of osteopontin (and therefore higher oxygen level in cancer cells), treatment with nimorazole did not significantly improve response to radiation therapy.
While additional studies are needed, this study suggests that identifying and treating patients with low oxygen levels in cancer cells may improve the outcome of radiation therapy for head and neck cancers. Patients with low levels of oxygen in their cancer cells (as measured by osteopontin levels in the blood) appear to benefit from use of a radiosensitizer to increase response to radiation therapy. Patients with head or neck cancer may wish to talk with their doctor about the risks and benefits of participating in a clinical trial of radiosensitizers or other promising therapeutic approaches.
Reference: Overgaard J, Eriksen JG, Nordsmark M et al. Plasma osteopontin, hypoxia, and response to the hypoxia sensitizer nimorazole in radiotherapy of head and neck cancer: results from the DAHANCA 5 randomised double-blind placebo-controlled trial. The Lancet Oncology. 2005. Early online publication August 30, 2005.
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