LUNG CANCER SCREENING REDUCES PROBABILITY OF QUITING SMOKING

NEW YORK (Reuters Health) Dec 17 - Men who screen negative for lung cancer are less likely to try to quit smoking than men whose scans are inconclusive, a Dutch study shows.

The findings add to the debate over whether patients will perceive negative results in a lung cancer screen as a license to smoke or a chance to quit.

A U.S. study out last month suggested imaging the lungs of current or former heavy smokers with so-called spiral CT could catch cancers early and reduce individuals' risk of dying from the disease by 20% compared to ordinary X-rays. (See Reuters Health story of Nov 4, 2010.)

Still, 300 smokers would have to be screened to save just one based on the U.S. study, and it is unclear if the scans, at about $300 each, will be cost-effective. And the false positive rate is high, raising questions about the risk to people who undergo unnecessary medical procedures as a result.

For the new study, Carlijn M. van der Aalst of Erasmus MC, University Medical Centre Rotterdam, and colleagues tapped into data from the NELSON trial, in which current or former smokers were randomized to lung cancer screening or no screening.

Along with negative and positive results, that screening arm included a third test outcome, "indeterminate." Men in that category were asked to come back for another CT scan a few months later.

As the researchers reported online December 9th in the European Respiratory Journal, during the next two years the men with inconclusive tests tried to quit more often than those with negative results, an average of 1.9 times versus 1.5.

Nine percent of men in the negative-results group reported prolonged abstinence, compared to 12% of men with inconclusive results, but the difference was not statistically significant.

The researchers found some hints that the more inconclusive test results a man had gotten, the more likely he was to be smoke-free. Prolonged abstinence climbed from 11% percent among men with one indeterminate test, to 16% among those with two or more inconclusive results.

In the no-screening arm, however, the prolonged abstinence rate was significantly higher, at 19%, as the research team reported in July 2010 in Thorax. In that same paper, they said that in the general population, about 3% to 7% of smokers quit - which suggests that screening might represent a teachable moment to encourage smokers to quit.

"More research is needed to investigate the opportunities of lung cancer screening in current as well as former smokers to promote health risk-reducing behavior change and to prevent relapses and to investigate what the most cost-effective approach is in this screening population," they write.

Eur Resp J. Posted December 9, 2010. Abstract