We agree with Drs. Carreras, Gorini, and Paci that the estimate of lung cancer deaths avertable by screening would be more informative if it were considered within the context of existing and more aggressive tobacco control policies (TCPs). We estimated that approximately 12,000 lung cancer deaths would be averted per year if the screening schemes adopted by the National Lung Screening Trial (NLST) were fully implemented among all screening-eligible populations in the United States in 2010. This number basically reflects the full potential of low-dose computed tomography screening as estimated by the NLST in reducing lung cancer deaths in the next 6 to 7 years in the United States, and it could serve as a benchmark for comparisons between screening and other lung cancer intervention measures, such as TCPs, which have a positive effect on all tobacco-related disease. Certainly, this estimate would change over time due to changes in smoking prevalence and population size, as well as improvements in imaging technology and lung cancer treatment. Thus, a long-term predictive comparison between screening and TCPs, as Dr. Carreras and colleagues performed recently, would be of greater relevance to policy makers focused on lung cancer control and prevention, although the uncertainty of long-term prediction is a challenge. It also is important when comparing TCPs with lung cancer screening that a significant fraction of new lung cancer cases are diagnosed in former smokers who ultimately did not benefit from the influence of TCPs. A mature tobacco-related disease control program should embrace all effective interventions.
To date, there are still several unanswered questions regarding lung cancer screening, such as its effectiveness in a younger or older population or in current/former smokers with a smoking history of less than 30 pack-years. In addition, it is still unclear whether implementation of screening will undermine or strengthen the effects of smoking cessation programs. Therefore, as stated in our article, future studies should consider not only tobacco control policies but also other factors that may affect the estimates of lung cancer deaths avertable by screening.
Jiemin Ma, PhD, MHS1
Ahmedin Jemal, DVM, PhD1
Robert Smith, PhD2
1Surveillance Research ProgramAmerican Cancer SocietyAtlanta, Georgia
2Department of Cancer ScreeningAmerican Cancer SocietyAtlanta, Georgia