This study has several important findings. Firstly, the demographic characteristics of smokers are different from those of former or never smokers. Secondly, smokers have markedly different beliefs about their risk of cancer, their understanding of screening test characteristics, and the benefits of treatment when the cancer is detected earlier. Thirdly, smokers are less willing to pay for this screening test and to undergo the appropriate treatment (in this case surgery) for a screen‐diagnosed cancer. Finally, smokers seem significantly less likely than former or never smokers to be willing to consider computed tomography screening for lung cancer than their non‐smoking counterparts. The combination of findings in our study suggest that there may be substantial obstacles to the successful implementation of a mass‐screening programme for lung cancer that is directed towards cigarette smokers.
That the demographics of smokers in this study are different from those of former or never smokers should not really come as a surprise. Data compiled from the 2001 National Health Information Survey documented that 22.8% of the adult population (46 million) of the US smoked.14
However, smoking rates within different subgroups of the population were vastly different. For example, the prevalence of smoking among those with a 9th–11th grade education (those aged 15–17 years or without a high school degree) was nearly 5 times higher (47%) than those with a graduate or doctoral degree (10%). A similar dichotomy held true when smoking rates were compared between those at or below the poverty level (31%) as opposed to those at or above the poverty level (23%). Lastly, African American men had higher smoking rates than their white counterparts.14
These data are important because they suggest that those with the highest smoking rates reside in that stratum of the population who have historically had poorer participation in screening programmes for various reasons.15,16,17,18,19
Smokers in this study were less likely to be able to identify any usual source of healthcare or claim a specific doctors' office as their usual source of healthcare. This has implications for screening because lack of an identifiable primary care provider is associated with a lower likelihood of participation in a screening programme.20,21,22
Our results show important differences between smokers and former or never smokers with regard to their attitudes about their risk of cancer and knowledge about the benefits of screening tests. Firstly, it seems that only about a quarter of the smokers believe that they are at risk for lung cancer, and about the same proportion say that a doctor told them they were at risk. Although this proportion was higher than that of former or never smokers, it is much lower than expected given the barrage of information available to smokers about cancer risk. The accuracy of the screening test and their risk of having the disease are less important to smokers when deciding whether or not to be screened than non‐smokers. In other established screening programmes, both of these factors have been shown to influence a person's willingness to be screened and have follow‐up treatment.23
It is troublesome that the only test characteristic regarding screening that is more important to smokers than their non‐smoking counterparts is the cost of the test.
Theoretical models exploring screening behaviour or healthcare beliefs for other commonly screened cancers have given some insight into why certain at‐risk groups (minorities, the poor, those without health insurance and the less educated) are less likely to be screened.24
A positive finding from this study pertains to former smokers. Although our data were not longitudinal in nature, it seems that when smokers quit, their attitudes towards screening become as or more favourable than those who have never smoked. Thus, if a mass campaign for lung cancer screening manages to screen large numbers of former smokers or if large numbers of smokers can be encouraged to quit during this process, we can expect to see significant health benefits among the population of former smokers.
These findings have implications that need to be considered. Should a public policy of screening for lung cancer with low‐dose computed tomography be undertaken? An analysis of cost‐effectiveness performed by Mahadevia et al25
suggested that periodic screening of about half of the 50 million smokers in the USA could cost approximately 116 billion dollars per year. Many of these patients would be of medicare age and thus would have health coverage similar to those in countries that have a national health insurance system. Any estimates of the potential yield in terms of reduction in mortality in such a screening programme will have to consider smokers' reduced willingness to be screened, and previous estimates of the benefits of a screening programme based on high compliance rates may need to be revised. For example, Mahadevia et al
estimated the incremental cost‐effectiveness to be $116
300 (2001 US$) per quality‐adjusted life year for smokers, and $2
700 per quality‐adjusted life year for former smokers, with the assumption that 93.5% of smokers would be adherent to lung cancer screening. This assumption was heavily weighted by adherent rates in a lung cancer screening study conducted in Olmsted County, Minnesota, in which 97% of patients were compliant with computed tomography cancer screening. However, this compliance rate was based on a population that had already consented to participate in a cancer screening study that included annual computed tomography scans for 4 years. Our survey suggests that current smokers' willingness to be screened may have been substantially overestimated. Such a revision in the adherence rate would result in significantly increased cost‐effectiveness estimates.25
Further, from this study, it seems that, in a population setting, more former smokers than current smokers would opt for screening. Although the cost‐effectiveness estimates for detecting a cancer in a former smoker are much higher than in a current smoker, the overall cost to the healthcare system could be substantially higher. Policy makers, whether in privately insured markets or within a national health system, may need to weigh the costs associated with a screening programme against the costs of programmes directed towards primary prevention of cigarette smoking, smoking cessation programmes or investments in the treatment for lung cancer.
This study has several limitations. Firstly, the findings may not be generalisable to other nations or healthcare systems. Although this study assesses attitudes towards screening, there is really no way of calculating the percentage of the population who would actually undertake screening. Secondly, we have no way of knowing whether self‐reported telephone surveys translate into actual practice. In at least one study, it seems that patients' self‐report, either by telephone or by mailing, of testing for other commonly screened cancers is higher than what can be documented in chart audits.26
This suggests that we can expect even less compliance with screening for lung cancer than reported here.
In summary, to realise major reductions in mortality, any screening programme must have the population comply with the screening test. This study shows that the health behaviours of smokers make them less likely to be interested in lung cancer screening. Nearly all of their responses suggest that their belief about this preventive health intervention is different from those of non‐smokers and will negatively affect their participation in a screening programme. As a lung cancer screening programme will be directed at current smokers and those with a smoking history, the overall reduction in lung cancer mortality that a mass screening effort can expect may be substantially diminished. Other already established screening programmes face a myriad of challenges in promoting widespread use. Lung cancer screening would face all of those challenges and now “reaching smokers” can be added to the list. Although a randomised controlled trial is necessary to establish a benefit to screening with low‐dose computed tomography, the results of this study suggest that innovative approaches to reach this difficult population should be developed and tested now if the promise of reducing the burden of lung cancer death is to be realised.