What is lung cancer?

Lung cancer begins when healthy cells in the lung change and grow to form a mass that is cancerous. These masses – which can be tumours, lesions or nodules – can occur anywhere in the lung and may later spread to other parts of the body (metastatic cancer).

There are two main types of lung cancer. The first is non-small-cell lung cancer (NSCLC), which accounts for around 85% of cases.1 NSCLC includes three subtypes of lung cancer based on similarities in how they are treated and their expected prognosis:

  • adenocarcinoma start in the cells that would normally secrete substances, such as mucus
  • squamous cell carcinoma start in flat cells that line the inside of the airways in the lung
  • large cell carcinoma can appear in any part of the lung.

The second type is small-cell lung cancer (SCLC). SCLC tends to grow and spread faster than NSCLC; about 70% of people with SCLC receive a diagnosis after the cancer has already spread.1 2

To understand some of the other key lung cancer terms used on this website, please see the glossary.

What is lung cancer?

Lung cancer places a huge burden on individuals and society

Most of us will know someone who has been affected by lung cancer. Across the world, lung cancer accounts for one in five cancer-related deaths.3

In 2020 alone, there were 2.2 million new diagnoses of lung cancer and 1.8 million deaths.4 Lung cancer is also responsible for around 46 million disability-adjusted life years (DALYs) each year.5

The risk of developing lung cancer depends on many factors, such as:6 7

  • age
  • smoking tobacco (including second-hand smoke)
  • air pollution
  • exposure to other carcinogens like asbestos or radon
  • family history of cancer
  • history of respiratory conditions, including chronic obstructive pulmonary disease (COPD).

Although smoking is currently the main cause of lung cancer, the number of people diagnosed with lung cancer who have never smoked is rising.8 This is partly why tobacco control alone, although important, will not help us address a challenge as pervasive as lung cancer.

Lung cancer places a huge burden on individuals and society

Lung cancer is often diagnosed too late

At a late stage of the disease, treatment options are limited and expected survival is poorest.9-11 In addition, clinical management is more complex when lung cancer advances, contributing to higher healthcare costs.12-14

Based on the latest data,9 15 over 40% of people with lung cancer are diagnosed at stage 4. At this stage, the proportion of people expected to still be alive five years after their diagnosis is tragically less than 10%.

In comparison, around 20% of people with lung cancer are diagnosed at stage 1, when the five-year survival rate is considerably higher at 68–92%.

The COVID-19 pandemic has caused further delays in the detection and diagnosis of lung cancer.16 17

Lung cancer is often diagnosed too late

Lung cancer does not affect everyone equally

Living with lung cancer can severely affect a person’s quality of life, as well as significantly impacting on  those close to them such as family and friends. Symptoms like breathlessness and fatigue, along with treatment and medical appointments, may lead to isolation and the need to take time off work.18-20

A loss of earnings can place people with lung cancer and their loved ones under financial pressure.21 22

The link between lung cancer and smoking also leads to widespread stigma, which may underpin why lung cancer often receives less attention and research funding than other common cancers.23 24

As a result, there are strong socioeconomic inequalities in diagnosis, treatment and survival of lung cancer.25-28

Lung cancer does not affect everyone equally

Screening can help to detect lung cancer early

Early detection of lung cancer by screening healthy people for the disease is essential, presenting us with the opportunity to both save lives and reduce the impact of lung cancer on our societies.10

For this reason, many countries are actively considering rolling out organised low-dose computed tomography (LDCT) screening for lung cancer.

With this in mind, the Lung Cancer Policy Network calls on governments to implement national lung cancer screening programmes using LDCT for all people at high risk of developing lung cancer.

Screening can help to detect lung cancer early

References

  1. American Cancer Society. What is lung cancer? [Updated 01/10/19]. Available from: https://www.cancer.org/cancer/lung-cancer/about/what-is.html [Accessed 27/04/21]

  2. Rudin CM, Brambilla E, Faivre-Finn C, et al. 2021. Small-cell lung cancer. Nat Rev Dis Primers 7(1): 3

  3. Ferlay J, Ervik M, Lam F, et al. 2020. GLOBOCAN 2020 cancer fact sheet: all cancers. Lyon: Global Cancer Observatory

  4. Ferlay J, Ervik M, Lam F, et al. 2020. Global Cancer Observatory: cancer today. [Updated 01/12/20]. Available from: https://gco.iarc.fr/today [Accessed 25/02/22]

  5. Institute for Health Metrics and Evaluation, University of Washington. GBD Compare, 2019. Available from: https://vizhub.healthdata.org/gbd-compare/ [Accessed 22/02/21]

  6. Corrales L, Rosell R, Cardona AF, et al. 2020. Lung cancer in never smokers: The role of different risk factors other than tobacco smoking. Crit Rev Oncol Hematol 148: 102895

  7. Cancer Atlas. 2019. Lung Cancer. Available from: canceratlas.cancer.org

  8. Kerpel-Fronius A, Tammemägi M, Cavic M, et al. 2021. Screening for Lung Cancer in Individuals Who Never Smoked: An International Association for the Study of Lung Cancer Early Detection and Screening Committee Report. J Thorac Oncol: 10.1016/j.jtho.2021.07.031

  9. Goldstraw P, Chansky K, Crowley J, et al. 2016. The IASLC lung cancer staging project: proposals for revision of the TNM stage groupings in the forthcoming (eighth) edition of the TNM classification for lung cancer. J Thorac Oncol 11(1): 39-51

  10. Lung Ambition Alliance and The Health Policy Partnership. 2021. Lung cancer screening: the cost of inaction. London: HPP

  11. Allemani C, Matsuda T, Di Carlo V, et al. 2018. Global surveillance of trends in cancer survival 2000–14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. The Lancet 391(10125): 1023-75

  12. Lung Cancer Europe. 2019. IV LuCE report on lung cancer: early diagnosis and screening challenges in lung cancer. Bern: LuCE

  13. Arrieta O, Quintana-Carrillo RH, Ahumada-Curiel G, et al. 2014. Medical care costs incurred by patients with smoking-related non-small cell lung cancer treated at the National Cancer Institute of Mexico. Tob Induc Dis 12(1): 1-9

  14. Haaf K, Tammemägi MC, Bondy SJ, et al. 2017. Performance and Cost-Effectiveness of Computed Tomography Lung Cancer Screening Scenarios in a Population-Based Setting: A Microsimulation Modeling Analysis in Ontario, Canada. PLoS Med 14(2): e1002225

  15. Heist RS, Engelman JA. 2012. SnapShot: non-small cell lung cancer. Cancer Cell 21(3): 448.e2

  16. World Economic Forum. 2021. Learning lessons from across Europe: prioritizing lung cancer after COVID-19. Geneva: WEF

  17. Hoehn RS, Zureikat AH. 2020. Cancer disparities in the COVID-19 era. J Surg Oncol 122(3): 371-72

  18. Lung Cancer Europe. 2020. 5th LuCE report on lung cancer: psychological and social impact of lung cancer. Bern: LuCE

  19. Brown CG, Brodsky J, Cataldo J. 2014. Lung cancer stigma, anxiety, depression, and quality of life. J Psychosoc Oncol 32(1): 59-73

  20. Wood R, Taylor-Stokes G, Smith F, et al. 2019. The humanistic burden of advanced non-small cell lung cancer (NSCLC) in Europe: a real-world survey linking patient clinical factors to patient and caregiver burden. Qual Life Res 28(7): 1849-61

  21. Macmillan Cancer Support. 2019. Health inequalities: time to talk. London: Macmillan Cancer Support

  22. Wood R, Taylor-Stokes G. 2019. Cost burden associated with advanced non-small cell lung cancer in Europe and influence of disease stage. BMC Cancer 19(214): 1-11

  23. Begum M, Urquhart I, Lewison G, et al. 2020. Research on lung cancer and its funding, 2004-2018. ecancer 14(1132): 1-13

  24. Hamann HA, Ver Hoeve ES, Carter-Harris L, et al. 2018. Multilevel opportunities to address lung cancer stigma across the cancer control continuum. J Thorac Oncol 13(8): 1062-75

  25. International Agency for Research on Cancer. 2019. Reducing social inequalities in cancer: evidence and priorities for research. Lyon: IARC

  26. Finke I, Behrens G, Weisser L, et al. 2018. Socioeconomic differences and lung cancer survival – systematic review and meta-analysis. Front Oncol 8(536): 1-20