Does Chronic Obstructive Pulmonary Disease (COPD) lead to Lung Cancer?
The development of Chronic Obstructive Pulmonary Disease (COPD) as well as Lung Cancer is primarily influenced by smoking. For us to make a distinction between the two as well as to understand how these are related to one another, we need to define COPD.
What is COPD?
COPD is a condition in which the damage to lung tissue reduces the elastic recoil of the lungs, causing shortness of breath. COPD occurs in the setting of emphysema and chronic bronchitis. Long-term exposure to airborne irritants like cigarette smoke and air pollutants leads to lung damage (Emphysema) and the superadded infections result in further lung damage and morbidity (Chronic Bronchitis). As a result, the airways and air sacs of the lungs lose their elasticity (ability to expand and shrink back), the walls of the air sacs may get thickened and the airways may produce more mucus than normal which can clog the airways and thus ‘obstruct’ the passage of air. Almost all cases of COPD are caused by tobacco smoking.
Is COPD related to the development of Lung Cancer?
COPD is indirectly related to the development of Lung Cancer in the sense that the precursors for the development of both conditions are primarily cigarette smoke and airborne irritants. Patients with COPD are at a higher risk of developing Lung cancer than those who don’t have COPD. COPD directly sets the stage for the development of lung cancer by damaging the cells of the lungs and placing greater stress on the repair mechanisms often to the point of exhaustion. This can lead to damage to the DNA of the cells. Such damaged cells may divide indefinitely and result in the development of lung cancer (Uncontrolled division of cells).
COPD is caused by a variety of environmental and genetic factors. According to an article published in BioMed research international 2019, Cigarette smoke increases capillary fluid leakage and inflammation in lung tissue. This leads to increased EMT (Epithelial-Mesenchymal Transition) and EndMT (Endothelial-Mesenchymal Transition) which increases the risk for tumorigenesis (development of cancer). The direct cell damage and repair in the setting of chronic inflammation also increases the risk of the development of lung cancer.
According to a pooled global study conducted at Harvard T.H. Chan School of Public Health; “Compared with non-COPD subjects, smoking behaviours showed a significantly higher effect on SCLC risk among COPD subjects, and further, COPD patients showed a 1.86-fold higher risk of SCLC.” Thus, COPD shows a direct causal pathway for the development of Small Cell Lung Carcinoma and warrants further research on the given topic.
The Difference between the Symptoms of COPD and Lung Cancer
While many of the symptoms of both COPD and Lung Cancer are similar such as shortness of breath, coughing, wheezing and chest tightness, there are certain key alarm features that clinically distinguish Lung Cancer from COPD. These are;
● Anorexia and cachexia (extreme weight loss and wasting of body). This weight loss is unexplained having no fathomable cause.
● Coughing up blood (Hemoptysis)
● Tiredness and Chronic fatigue
● Chest pain
● Loss of appetite
● Hoarseness of voice
● A chronic cough that gets worse and does not go away
Preventive Measures for COPD
The best preventions against COPD are;
● Cessation of smoking or should not start smoking in the first place.
● Reduction of exposure to airborne noxious stimuli. This may be done in a variety of ways like wearing face masks. etc.
● Reducing the exposure to Second-Hand Smoke (smoke from the burning end of a cigarette or the smoke inhaled from the smoking by another person).
● Getting counselling or joining support groups to help quit smoking. Using products that help wean you off smoking.
● Pulmonary rehabilitation.
● Maintaining a healthy lifestyle and having an exercise routine. A study in the American Journal of Respiratory and Critical Care Medicine indicated that physical exercise protects against the development of COPD as well as its progression.
● Early detection of COPD by chest X-ray (hyperinflated lungs, tubular heart and decreased vascular markings) and PFT (Pulmonary Function Testing).
● Breathing Exercises and Chest Physiotherapy.
● Taking occupational precautions in case of high exposure to smoke.
● Coordinated community research and awareness for better management of COPD and Lung Cancer at the level of the community.
● Annual flu vaccination and pneumococcal vaccination to help prevent respiratory infections and chronic bronchitis.
In short, COPD is one of the most prevalent respiratory illnesses (2.3% of the Singaporean population has COPD) and awareness and appropriate prevention can reduce significant morbidity and mortality thus improving quality of life.
References
1) https://www.sciencedirect.com/science/article/pii/S235239641530147X
2) Hou, W., Hu, S., Li, C., Ma, H., Wang, Q., Meng, G., Guo, T., & Zhang, J. (2019). Cigarette Smoke Induced Lung Barrier Dysfunction, EMT, and Tissue Remodeling: A Possible Link between COPD and Lung Cancer. BioMed research international, 2019, 2025636. https://doi.org/10.1155/2019/2025636
3) https://www.cdc.gov/cancer/lung/basic_info/symptoms.htm
4) Garcia-Aymerich, J., Lange, P., Benet, M., Schnohr, P., & Antó, J. M. (2007). Regular physical activity modifies smoking-related lung function decline and reduces risk of chronic obstructive pulmonary disease: a population-based cohort study. American journal of respiratory and critical care medicine, 175(5), 458–463. https://doi.org/10.1164/rccm.200607-896OC
