According to an early online article recently published in the journal Thorax, a blood test may help to detect lung cancer in its early stages, when the disease is most treatable. However, further study is needed to determine the true benefit of this test.
Lung cancer is responsible for more deaths every year in the United States than breast cancer, colon cancer, and prostate cancer combined. One of the main reasons that lung cancer remains so deadly is that it is often diagnosed once it has spread from its site of origin. In an effort to diagnose the disease in its earliest and most treatable stages, research is focused on identifying effective screening measures for lung cancer.
In order for new screening methods to be adopted into routine clinical care, the measures must identify cancer early enough to improve outcomes, must be economically feasible, and must detect cancer to an acceptable degree of accuracy. As well, in order to encourage patient compliance, screening measures must not be too invasive, painful, or have the potential for extreme side effects. To date no screening measures for lung cancer have been identified that provide a confirmed benefit.
Researchers from England and Germany recently conducted a clinical trial to evaluate the effectiveness of a blood test in detecting lung cancer. This trial included plasma (component of blood) from 50 patients who were healthy at the time of the initiation of the trial; 82 patients who had been diagnosed with non–small cell lung cancer; and 22 patients who had been diagnosed with small cell lung cancer. Researchers evaluated levels of seven different autoantibodies; autoantibodies are proteins (antibodies) made by the immune system that are directed against one or more of the individual’s own proteins, meaning they mistakenly target and damage specific tissues or organs of the body.
- Levels of at least one of the seven tested antibodies were raised in 76% of all patients with lung cancer compared with only 8% of healthy individuals.
- Levels of antibodies were elevated in 89% of patients with lung cancer that had not spread to nearby lymph nodes (node-negative).
- Of the cases in which antibodies levels were raised, 92% correctly identified cancer (specificity).
The researchers concluded that testing for levels of specific antibodies in the plasma of patients “is non-invasive, [and] cost effective relative to imaging tests, carries no side effects and is acceptable to the vast majority of patients.” Further research is necessary to confirm these findings.
Patients who are at a high risk of developing lung cancer may wish to speak with their physician regarding their individual risks and benefits of participating in a clinical trial further evaluating screening measures. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov) and www.eCancerTrials.com.
Reference: Chapman C, Murray A, McElveen J, et al. Autoantibodies in lung cancer – possibilities for early detection and subsequent cure. Thorax [early online publication]. October 11, 2007. doi:10.1136/thx.2007.083592.