For the first time, researchers can predict the lung cancer risk for social smokers as well as habitual smokers.
Data presented today at the annual meeting of the Radiological Society of North America (RSNA) showed that a social smoker age 50 or older has a risk for developing lung cancer similar to that of a smoker under age 50 who smoked three packs a day for 20 years.
Claudia I. Henschke, Ph.D., M.D., is the principal investigator of the International Early Lung Cancer Action Project (I-ELCAP), the largest study ever undertaken on whether annual screening by computed tomography (CT) can prevent deaths from lung cancer. I-ELCAP numbers were derived from the screenings of 27,701 men and women, some starting in 1993 at 35 international institutions.
"Based on our data, we can now predict, by age, by how much has been smoked or when a smoker has quit, what is the likelihood of developing lung cancer," said Dr. Henschke, a professor of radiology and division chief of chest imaging at New York-Presbyterian Hospital/Weill Cornell Medical Center in New York City.
"Annual CT screening identifies a high percentage of Stage I diagnoses of lung cancer, the most curable form of lung cancer," Dr. Henschke said. "Our study found that deaths from Stage I lung cancer were surprisingly low after surgery, but only if treatment is pursued. Delaying treatment by more than six months resulted in increased tumor disease and often a higher stage of the disease."
Smokers should consult their doctors to determine at what age CT screening should begin, but this data provides the basis for such recommendations. With annual screening, there is a 76-78 percent chance of a smoker's lung cancer being cured, Dr. Henschke said. Without screening, the probability for cure falls to 5-10 percent.