There are several related topics in addition to the primary outcomes of lung cancer screening which are of interest: the ‘Big 3’ smoking-induced diseases (lung cancer, COPD, coronary heart disease), smoking cessation, and gender differences.
The Big 3 smoking-induced diseases measured in a single CT imaging examination: lung cancer, coronary heart disease, and COPD.
Like lung cancer, coronary heart disease (CHD), and chronic obstructive pulmonary disease (COPD) also have high 1) incidence and mortality rates, 2) are related to smoking, and 3) are measurable through imaging biomarkers. These biomarkers are 1) the volume doubling time (VDT) of lung nodules for lung cancer, 2) coronary artery calcium for CHD, and 3) emphysema for COPD, as measured by chest Computed Tomography (CT) imaging.
For these Big 3 diseases, early treatment has been shown to delay or stop progression and allow therapy at a treatable stage in a large number of patients. Currently, treatment for these diseases is mostly initiated at a relatively late stage, often after the first clinical symptoms have been observed. The impact on disease burden can be significantly less if the diseases are caught at a subclinical stage. Therefore, the prevention and/or early treatment of all these diseases is of growing importance.
Participants in lung cancer screening programmes have higher smoking cessation rates than the non-screened smoking population. For smoking cessation services, this could be used as an additional tool to motivate individuals to quit . Smoking cessation has an impact on more than just lung cancer; it also affects a wide spectrum of smoking-related health problems, including CHD and COPD . The combination of lung cancer screening and a smoking cessation programme could substantially reduce lung cancer mortality , as well as impacting these other comorbidities. Similar results were found in a modelling study .
The biological sex of lung cancer screening participants has a large differential effect on the results; both the NLST and NELSON studies showed that screening is more effective for women than it is for men [18, 19]. There are also sex-based differences in the biological characteristics of lung cancer, including histology and aggressiveness. These differences provide further opportunities to improve lung cancer screening by taking biological sex into account.
Gender differences can be expected to influence the recruitment process, the CT screening and the screening test result, the health seeking behaviour of the participants, and whether participants commit to health behavioural changes (smoking cessation). However, there is at present a lack of evidence about gender differences in lung cancer screening. To optimise future lung cancer screening, the full effect of gender needs to be understood in order to enhance autonomous informed decisions about screening uptake, healthcare seeking behaviour, and treatment.