According to a recent article published in the Journal of Clinical Oncology, free DNA found in circulating blood appears to be an accurate marker for detecting lung cancer.
Lung cancer is the leading cause of cancer deaths in the United States. One main reason that lung cancer remains so deadly is that the majority of patients diagnosed with lung cancer already have extensive disease. Once lung cancer has spread from the lung to several and/or distant sites in the body, it is often considered incurable. To improve survival rates for this disease, detection of lung cancer must occur prior to spread. Currently, there has been no definitive evidence that chest x-rays have the sensitivity capabilities necessary to detect lung cancer early enough to obtain acceptable rates of survival. There have been results from at least one clinical trial indicating an improvement in survival with the use of CT (computed tomography) and PET (positron emission tomography) screening in patients at a high risk of developing lung cancer; however, further clinical trials are necessary to confirm this finding.
2 In addition, routine CT scans in high-risk patients would ultimately place a large financial burden on the medical system, as well as consume time of the patient. In addition, nodules found on scans may not be cancerous – leading to unnecessary biopsies. Researchers continue to evaluate ways to detect lung cancer early enough so that early intervention can improve survival, while weighing rates of unnecessary biopsies and finances associated with screening.
Researchers from Italy recently conducted a clinical trial to evaluate the accuracy of DNA found in circulating blood as a marker for the existence of lung cancer. DNA circulating in the blood is thought to be released from the cancer; however, the origin and biological mechanisms of circulating DNA are not clearly understood at present. This trial involved 100 patients who had been newly diagnosed with lung cancer, with stages I – IV (earliest stage to most advanced stage). Blood was drawn and tested for DNA in this group of patients and compared with blood drawn from individuals who were heavy smokers but did not have lung cancer, as well as a group of individuals who were not smokers and did not have lung cancer (the latter two are the control group). DNA levels in the blood were 8 times higher in patients with lung cancer, compared to the control group. These elevated levels pertained also to patients with early-stage cancer. Only patients with cancer had high levels of DNA in their blood. The rate at which elevated DNA levels accurately detected lung cancer was 90%.
These researchers concluded that measuring circulating DNA appears to be an accurate and quick method of detecting lung cancer, even in its earliest stages. Future clinical trials are necessary to confirm this finding and advance this procedure into mainstream use for screening of individuals at a high risk of developing lung cancer. Patients who are at a high risk of developing lung cancer may wish to speak with their physician about the risks and benefits of participating in a clinical trial for screening of lung cancer. Two sources of information regarding ongoing clinical trials include the National Cancer Institute ( cancer.gov) and www.cancerconsultants.com. Personalized clinical trial searches on behalf of patients are also performed at cancerconsultants.com.
1.Sozzi G, Conte D, Leon M, et al. Quantification of free circulating DNA as a diagnostic marker in lung cancer.
Journal of Clinical Oncology. 2003;21:3902-3908.
2.Pastorino U, Bellomi M, Landoni C, et al. Early lung-cancer detection with spiral CT and positron emission tomography in heavy smokers: 2-year results.
The Lancet. 2003;362:593-597.
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