The glossary explains some of the words used across this website and covers some key cancer and research terms, which primarily focus on lung cancer.


A standard measure of the amount of cigarettes a person has smoked during their lifetime. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years a person has smoked. For example, one pack-year is equal to smoking one pack per day for one year, or two packs per day for half a year, and so on.1

Participation rate

The number of people invited for screening who attend a screening unit and undergo a scan. It is also referred to as ‘uptake’.2 See also ‘Organised screening’ and ‘Targeted screening’


The preliminary roll-out of an organised programme across designated sites or a geographic region. Pilots usually assess the performance of a programme rather than outcomes.3 The terms ‘pilot’, ‘feasibility study’ and ‘implementation study’ are often used interchangeably. Although definitions vary, they usually share common research objectives around the implementation of an intervention.4 See also ‘Feasibility study’ and ‘Implementation study’


A measurement of the burden of a disease in a population. It is the number of people who have a particular disease per 100,000 population at a specific point in time or during a specific period.5 See also ‘Incidence’

Primary prevention

A risk-reduction strategy that targets individuals before a disease first develops. For example, interventions may be designed to prevent exposure to risk factors for lung cancer, such as smoking.3 See also ‘Secondary prevention’ and ‘Risk factor’

Prospective study

A study that typically recruits a cohort of people before they receive an intervention, to see how they respond over a long period of time. These studies are designed to observe participant outcomes, such as new cases of lung cancer, and analyse this in relation to exposure to certain risk factors for a disease or an intervention, such as screening during the study period.6 For this reason, prospective studies usually have fewer potential sources of bias than retrospective studies.7 See also ‘Cohort studies’ and ‘Retrospective study’


A term relating to anything that affects or might occur in the lungs.8


  1. National Cancer Institute. NCI Dictionary of Cancer Terms.  Available from: [Accessed 04/03/22]

  2. Baldwin DR, Brain K, Quaife S. 2021. Participation in lung cancer screening. Translational lung cancer research 10(2): 1091-98

  3. World Health Organization. 2020. WHO report on cancer: setting priorities, investing wisely and providing care for all. Geneva: WHO

  4. Abbott JH. 2014. The distinction between randomized clinical trials (RCTs) and preliminary feasibility and pilot studies: what they are and are not. Journal of Orthopaedic & Sports Physical Therapy 44(8): 555-58

  5. Global Lung Cancer Coalition. 2022. Glossary.  Available from: [Accessed 04/03/22]

  6. Ranganathan P, Aggarwal R. 2018. Study designs: Part 1 – An overview and classification. Perspect Clin Res 9(4): 184-86

  7. Norvell DC. 2010. Study types and bias: Don’t judge a study by the abstract’s conclusion alone. Evid Based Spine Care J 1(2): 7-10

  8. Merriam-Webster. Dictionary.  Available from: [Accessed 30/03/22]