Personalized, Gene-Based Risk Testing for Lung Cancer Helps Smokers Quit

Smokers who learn their personal risk of lung cancer through gene-based risk assessment tools are more likely to be motivated to quit their habit, according to recent findings.

The Respiragene test, which utilizes genetic markers and clinical variables to inform smokers of their risk of developing lung cancer compared with other smokers, can help counteract a tendency to underestimate their personal risk of smoking complications, Dr. W. Jeffrey Allard, clinical affairs director of Synergenz Bioscience, Ltd. (Auckland, New Zealand), told a conference on smoking cessation on September 30, 2009.

An increasing amount of evidence shows that smokers respond to personalized risk information with higher quit rates, reported Dr. Allard, a featured speaker at the 3rd Smoking Cessation Conference, held in Philadelphia, PA, USA. "Many current smokers suffer from ‘optimistic bias,' the belief that while smoking is bad for them, the illness and early death that come with it affects other smokers, not them,” he said. "But at the same time, when offered the chance to find out where they actually stand, studies also show that smokers are very interested in learning their own risk levels, and in many cases take this personal information as a trigger to prompt them to quit,” he said, citing an extensive review article on the topic soon to be published in Postgraduate Medical Journal (PMJ).

According to Dr. Allard, quit rates were highest where smokers had suffered, or appeared to be at immediate risk of, life-threatening complications caused by smoking. Lung cancer, heart attack, and emphysema are particularly important in this regard.

An encounter with serious illness increases the likelihood of quitting: quit rates after a life-threatening event such as a heart attack or lung cancer are as high as 50-60%. But by the time many smoking-related diseases appear, the consequences are usually serious and often fatal: lung function loss and related damage associated with chronic obstructive pulmonary disease (COPD), or emphysema, is generally irreversible; heart attacks can be deadly; and a diagnosis of lung cancer means death within one year for 50% of those diagnosed, and death within two years for 80%.

However, the predictive personal information based on genetics can communicate individual risk before serious illness emerges, so it can be a valuable tool for doctors to help them identify those at higher risk for targeted efforts at help with smoking cessation and closer monitoring for possible smoking-related illness, according to Dr. Allard.

Dr Allard's company, Synergenz, has partnered with PHD Diagnostics, LLC to market Respiragene, a genetic-based lung cancer-susceptibility test developed by PHD's clinical lab division, Molecular Diagnostics Laboratories (MDL), specifically for use in the United States. MDL, which is a Clinical Laboratory Improvement Amendments (CLIA)-registered, specialist lab with molecular diagnostics development expertise, launched the test earlier in September 2009.

The Respiragene test combines genetic and nongenetic factors to generate a score showing an individual's risk of lung cancer compared with the average smoker. An average smoker is already 20 to 30 times more likely to develop lung cancer than nonsmokers, and about one in 10 will develop lung cancer.

According to Dr. Allard, that among all smokers, some are at considerably higher risk. The test places chronic smokers and ex-smokers in three categories. A moderate risk score means the person has a risk of developing lung cancer comparable to an average smoker. Those with high risk scores are about four times more likely than those at moderate risk to get lung cancer, and those at very high risk are approximately 10 times more likely to get the disease.

Lung cancer is one of the major causes of smoking-related deaths, killing more people in the United States than any other type of cancer. It accounted for more than 160,000 deaths in 2007, more deaths than from breast cancer, prostate cancer, and colon cancer combined. Studies show that lung cancer results from the combined effects of smoking and genetic susceptibility.

Informing smokers of their own personal risk of illness, which borrows a technique that is already a mainstay in heart disease prevention, will provide a new tool for clinicians to engage their patients, said Dr. Allard, who added that recent behavior research also found that such testing does not discourage smokers from quitting even though they might not be identified at the greatest risk. The test is also a reminder to those smokers who do not consider themselves at risk of lung cancer at all that all smokers are at some risk. A recent study revealed that as much as 50% of smokers do not think they are at risk despite well-publicized warnings.

The Respiragene test is available from Molecular Diagnostics Laboratories via their website. The test must be authorized by a physician.

Synergenz BioScience markets respiratory risk-assessment technologies first discovered by Dr. Robert Young in research conducted at New Zealand's University of Auckland in its Schools of Medicine and Biological Sciences, where clinical studies continue in collaboration with leading academic and commercial partners worldwide.

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