Relationships between chronic obstructive pulmonary disease and lung cancer: biological insights

Our plain-English summary of Relationships between chronic obstructive pulmonary disease and lung cancer: biological insights, by E. Barreiro, V. Bustamante, V. Curull, et al (Journal of Thoracic Disease, 2016).

The study

• Authors: E. Barreiro, V. Bustamante, V. Curull, J. Gea, J.L. López-Campos, X. Muñoz
• Journal: Journal of Thoracic Disease
• Published: 2016;8(10):E1122-E1135
• Type of article: Review
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Lung cancer (LC) has become one of the leading causes of preventable death in the last few decades. Cigarette smoking (CS) stays as the main etiologic factor of LC despite that many other causes such as occupational exposures, air pollution, asbestos, or radiation have also been implicated. Patients with chronic obstructive pulmonary disease (COPD), which also represents a major cause of morbidity and mortality in developed countries, exhibit a significantly greater risk of LC. The study of the underlying biological mechanisms that may predispose patients with chronic respiratory diseases to a higher incidence of LC has also gained much attention in the last few years. The present review has been divided into three major sections in which different aspects have been addressed: (I) relevant etiologic agents of LC; (II) studies confirming the hypothesis that COPD patients are exposed to a greater risk of developing LC; and (III) evidence on the most relevant underlying biological mechanisms that support the links between COPD and LC. Several carcinogenic agents have been described in the last decades but CS remains to be the leading etiologic agent in most geographical regions in which the incidence of LC is very high. Growing evidence has put the line forward the implications of COPD and especially of emphysema in LC development. Hence, COPD represents a major risk factor of LC in patients. Different avenues of research have demonstrated the presence of relevant biological mechanisms that may predispose COPD patients to develop LC. Importantly, the so far identified biological mechanisms offer targets for the design of specific therapeutic strategies that will further the current treatment options for patients with LC. Prospective screening studies, in which patients with COPD should be followed up for several years will help identify biomarkers that may predict the risk of LC among these patients.

In plain English

This article is a narrative review. It does not report a single new study, although it mentions some unpublished observations from the authors' own group. It had three parts: the main causes of lung cancer, studies on whether people with chronic obstructive pulmonary disease (COPD) have a higher lung cancer risk, and the biological processes that might link the two. Cigarette smoking was described as the main cause. Among other causes, the review briefly discussed asbestos. It cited early studies from the United Kingdom and United States in which textile and insulation workers had a significantly higher lung cancer risk than unexposed people. It stated that asbestos-related lung cancer depends on how long exposure lasted and is significantly increased by smoking. No specific asbestos fiber types were named. The review cited an estimate that occupational exposures account for 9% to 15% of lung cancer. On the biological links, it described research on chronic inflammation and oxidative stress. The authors concluded that COPD represents a major risk factor for lung cancer, and they called for prospective screening studies of COPD patients.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Narrative review of published literature, with some unpublished observations from the authors' group
• Who was studied: No patients were studied for this article. It reviewed published studies on lung cancer causes, on COPD and lung cancer risk, and on biological mechanisms. It also mentioned unpublished observations from the authors' group in patients with lung cancer with and without COPD.
• Exposure: Mainly cigarette smoking. Occupational agents were also reviewed, including asbestos (described only as fibers of silicate minerals, with no fiber type named), tar, soot, arsenic, chromium, nickel, silica dust and diesel exhaust. Radiation, radon and air pollution were also covered.
• Main results:
  • Citing earlier studies, the review stated that textile and insulation workers in the United Kingdom and United States had a significantly higher lung cancer risk than non-exposed individuals.
  • Citing earlier studies, the review stated that asbestos-induced lung cancer depends on the duration of exposure and is significantly increased by cigarette smoking, which may favor retention of asbestos fibers in the lungs.
  • Citing a guideline, the review stated that occupational exposure has been estimated to contribute 9% to 15% of lung cancer.
  • Citing other studies, the review stated that in patients with moderate-to-severe COPD, lung cancer prevalence can be up to five times that of smokers without COPD.
  • An earlier study by the authors' group found higher protein carbonylation (an oxidative damage marker) in the normal airway lining of lung cancer patients, especially those with COPD.
  • In unpublished observations, the authors' group found significantly greater Th1 cytokine levels in the tumors of lung cancer patients with COPD than in those without COPD.
• The authors' conclusion: The authors concluded that COPD represents a major risk factor for lung cancer, and that the biological mechanisms identified so far offer targets for treatment design. They said prospective screening studies following COPD patients for several years will help identify biomarkers of lung cancer risk.
• Limitations the authors state:
  • The authors said their unpublished finding of a greater M1/M2 macrophage ratio in tumors of lung cancer patients with COPD needs further research to confirm the hypothesis that these patients may have a better prognosis.
  • The authors said more research is needed before antioxidants can be included in lung cancer guidelines as therapies.

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Occupational Exposure, COPD, Carcinogenic, Emphysema, Biomarker.

Related studies

• The relative importance of clinical, radiological and pulmonary function variables in evaluating asbestosis and chronic obstructive airway disease in asbestos workers — G.M. Regan, B. Tagg, et al. (1971)
• Incident chronic obstructive pulmonary disease associated with occupation, industry, and workplace exposures in the Health and Retirement Study — S.R. Silver, W.A. Alarcon, et al. (2021)
• Total lung capacity. An insensitive measure of impairment in patients with asbestosis and chronic obstructive pulmonary disease? — S. Barnhart, L.D. Hudson, et al. (1988)
• A somatic TSHR mutation in a patient with lung adenocarcinoma with bronchioloalveolar carcinoma, coronary artery disease and severe chronic obstructive pulmonary disease — J.W. Kim, S. Lee, et al. (2012)
• Chronic obstructive lung diseases and risk of non-small cell lung cancer in women — A.G. Schwartz, M.L. Cote, et al. (2009)
• Relationship between lung biopersistence and biological effects of man-made vitreous fibers after chronic inhalation in rats — T.W. Hesterberg, W.C. Miiller, et al. (1994)

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