New Zealand researchers said Tuesday they have developed the world's first test to measure the risk for individual smokers and ex-smokers of developing lung cancer.
The test combines results of DNA analysis with other risk factors such as age, diseases such as bronchitis and emphysema and family lung cancer history, said University of Auckland associate professor Robert Young.
"All smokers face an increased risk of developing lung cancer, among a host of other serious health problems, but for some individuals the risk is much greater than for others," Young said.
"With this test, doctors will be able to identify those at greatest risk while there is still time to help."
The test obtains a patient's DNA from a simple mouth swab.
Lung cancer is the most lethal of common cancers, with half of all sufferers dying within a year of diagnosis and 80 percent within two years.
The risk can be lowered by quitting smoking, and survival rates improve dramatically if the disease is detected early.
Young said research suggested many smokers had an optimistic bias, believing the disease would affect other smokers rather than them.
The new test could help overcome this optimistic bias by showing patients their individual susceptibility to lung cancer.
Early evidence suggested that identifying higher-risk patients may also allow better monitoring for early detection of the disease.
The test, trade named Respiragene, generates a score putting smokers and ex-smokers into categories of moderate, high risk and very high risk of developing lung cancer.
Average smokers with a moderate risk are 20 to 30 times more likely to develop lung cancer than non-smokers, and about one in 10 average smokers will develop lung cancer.
People categorised as high risk are about four times more likely than an average smoker to get lung cancer, and those with a very high risk are about 10 times more likely to get the disease.
"The test results may help patients decide, with their doctor, to get help to quit smoking and how closely they should be monitored for lung cancer going forward," said Young.
The test, developed by a company spun off from the University of Auckland called Synergenz Bioscience, is expected to be available worldwide before the end of the year.
Wellington respiratory doctor Peter Martin told the Dominion Post newspaper the technology was an extremely interesting scientific breakthrough.
But he warned its purpose was not to identify smokers who could "happily go on smoking" because even those with a moderate risk were at least 20 times as likely as non-smokers to develop lung cancer.