The cumulative impact of changes in smoking behavior that started in the mid-1950s averted approximately 795,851 U.S. lung cancer deaths, 552,574 among men and 243,277 among women from 1975 to 2000, according to a report in the Journal of the National Cancer Institute. The researchers also estimated that more than 1.6 million lung cancer deaths among men and more than 880,000 among women might have been averted if all smokers had quit in response to the Surgeon General’s first Report on Smoking and Health issued in 1964.
A consortium of six universities and research centers developed independent models to estimate the impact of tobacco control policies on lung cancer mortality. “The models explicitly consider factors associated with the risk of smoking, including the number of cigarettes smoked per day, the age of initiation, and the number of years quit,” the investigators stated. “The prevalence of smoking and lung cancer deaths under three scenarios were considered: actual tobacco control, based on historical changes in smoking rates; no tobacco control, based on predicted smoking rates if tobacco control had not been enacted; and complete tobacco control, which considers what might have happened if all smoking ceased in 1965,” the authors explained. “The models yielded a range of results for the numbers of lung cancer deaths among the three smoking scenarios, but the estimates of the fraction of lung cancer deaths averted were reasonably consistent across models,” the authors noted.
“The main message of these analyses is clear. Tobacco control strategies implemented mid-century have averted hundreds of thousands of lung cancer deaths in the United States during the period 1975 to 2000, but these are only approximately 30% of the lung cancer deaths that could have been averted had all cigarette smoking ended in 1965,” the investigators stated. They attributed this to several factors: lag time between the Surgeon General’s Report and the time it took for smoking rates to decline; smokers’ risk of lung cancer remaining elevated for years after they quit; and “a sizable fraction of the population” who continued to smoke.
“Clearly, further reductions in smoking rates will be required to reduce lung cancer incidence and mortality rates substantially,” the authors concluded. “The recently reported 20% reduction in lung cancer mortality as a result of early detection using low-dose spiral CT suggests that screening of high-risk individuals may play a role in reducing mortality from this disease. Because risk of lung cancer remains elevated for a long time among smokers who quit, effective screening techniques may have a role in reducing lung cancer mortality among ex-smokers. However, continued implementation of evidence-based tobacco control policies, programs, and services remains the most promising approach to reducing the burden of lung cancer.”■
Moolgavkar SH, et al: J Natl Cancer Instit 104:541-548, 2012.