A Breath of Hope: Redefining Lung Cancer Outcomes with Modern Medicine
By: Zainab Al-Attwani, Gissou Jafari Torreie, Luca LeClair, Raymond Zeng
Introduction
Despite advances in our understanding of risk factors and treatments, lung cancer remains the leading cause of cancer-related deaths globally (Oliver, 2022). It is classified into two main types: non-small cell lung cancer (NSCLC), which accounts for over 85% of cases (Herbst et al., 2018), and small cell lung cancer (SCLC), known for its rapid metastasis and progression (Lee et al., 2023). Smoking is the primary risk factor for lung cancer; however, genetics, air pollution, and other environmental factors may also contribute to tumour development (Nooreldeen & Bach, 2021). Common symptoms include persistent coughing, shortness of breath, weight loss, and chronic fatigue (Simoff et al., 2013). This article will further explore the causes, current treatments for lung cancer, and emerging advancements in treatment approaches.
Causes and Risk Factors Associated with Lung Cancer
A mixture of lifestyle choices, environmental exposures, and family history can cause or increase one’s chances of developing lung cancer. Some of these factors include, but are not limited to, smoking, radon, asbestos, family history of lung cancer, air pollution, and workplace exposure to cancer causing agents (American Cancer Society, 2024).
Smoking
Tobacco smoking is the leading cause of lung cancer and lung cancer deaths. Individuals are 15 to 30 times more likely to develop or die from lung cancer as a result of smoking (Centers for Disease Control and Prevention, 2024). An estimated 75% of lung cancer related deaths in Canada are due to smoking (Canadian Cancer Society, 2024). There is also a correlation between smoking frequency and risk of cancer development – individuals that smoke more (quantity-wise) and have a lengthier history of smoking are at a significantly greater risk of acquiring the disease (American Cancer Society, 2024). Furthermore, those who do not smoke also have a serious potential of developing lung cancer. Inhalation of another’s smoke, known as “secondhand smoke”, exposes an individual to the same toxins that are being inhaled by the smoker (American Cancer Society, 2024).
Tobacco smoke contains over 7000 chemicals, with more than 70 of these chemicals being known to cause cancer in both animals and humans (Centers for Disease Control and Prevention, 2024). Specifically, 20 chemicals have been identified as being lung cancer causing agents/carcinogens (Hecht, 2012). Most of the carcinogens can be classified as being either a polycyclic aromatic hydrocarbon (PAH), nicotine-derived nitrosamine ketone (NNK), volatile (e.g. 1,3-butadiene and ethylene oxide), or metal (e.g. cadmium) (Hecht, 2012).
It is well established that smoking marijuana can irritate the lungs, but there is less data that examines the relationship between marijuana and lung cancer (American Cancer Society, 2024). The criminalization of marijuana in many locations made it hard to study this link and studies that did study the drug often used participants that smoked both tobacco and marijuana, making it hard to attribute any single health outcome to marijuana (American Cancer Society, 2024). However, there are good reasons to suggest that smoking marijuana can increase the risk of lung cancer: marijuana smoke contains tar, a carcinogenic substance also found in tobacco smoke; and because of the nature of how marijuana is smoked, the smoke is inhaled deeper and held longer within the lungs, giving harmful substances a greater chance of depositing (American Cancer Society, 2024).
Radon
Radon is a naturally occurring radioactive gas that can be found within soil and rocks (American Lung Association, 2024). It can enter residential homes and other buildings through structural flaws found in the walls and floors, windows, and drains, and accumulate over time . Those situated closer to the ground (e.g. living in basements) or in poorly ventilated areas, are more exposed to the gas. Unfortunately, due to its colourless, odourless, and tasteless character, it can be hard to detect (Government of Canada, 2023). Over time, the gas is inhaled and causes damage to the lungs. For individuals who smoke, the risk of developing lung cancer is increased when radon exposure is taken into account (Centers for Disease Control and Prevention, 2024).
Asbestos
Asbestos is a group of naturally occurring “minerals that are resistant to heat and corrosion” (National Cancer Institute, 2022). For this reason, they are suitable materials that are commonly used in the construction of buildings and cars (Ragland, 2023). When asbestos is disrupted, it breaks into fibers that are suspended in the air (National Cancer Institute, 2022). Accumulation of these fibers in an individual’s lungs can lead to various types of cancers including lung cancer. Most individuals are exposed to asbestos at low concentrations, although the risk of lung cancer is unknown at this level. The heaviest exposure usually occurs in the workplace, especially in the construction, demolition, and repair industries, increasing lung cancer risks for the workers(National Cancer Institute, 2022).
Family history of lung cancer
An individual’s risk of lung cancer is increased when a family member(s) has or has had lung cancer. There is evidence that genes have a role to play, and it has been found that around 8% of cases are due to genetics (Ragland, 2023). Additionally, family members tend to share similar surrounding environments, which could contribute to similar risks. Regardless, both contributions put an individual at an increased disposition of acquiring lung cancer (Centers for Disease Control and Prevention, 2024). The only limitation involved when considering family history is that the correlation between genetics and the shared environment is unclear.
Air pollution
The air is polluted with a wide variety of particles that can include chemicals, dust, and metals (Ragland, 2023). These particles can become trapped within the lungs when inhaled, potentially increasing one’s risk of lung cancer. However, air pollution plays a marginal role in risk elevation compared to some of the other risk factors/causes already discussed. Furthermore, there are a few simple ways to mitigate this risk factor, such as monitoring the air quality provided by forecasts and remaining indoors when air pollution levels are high (Ragland, 2023). In the States, only 1% to 2% of lung cancer deaths have been attributed to outdoor pollution (American Cancer Society, 2024).
Workplace exposure to cancer causing agents
Many cancer causing agents, known as carcinogens, are used in the workplace. Many of these industries are related to manual labour, but are not limited to it. Workplace exposure can subject workers to significantly greater levels of carcinogens than the average individual would be. This point was briefly addressed during a previous section on asbestos. Exposure to carcinogens can occur through inhalation, absorption through the skin, and less commonly, ingestion (WorkSafeBC, 2024). Other inhaled chemicals besides asbestos include arsenic (used in electronics and glass manufacturing), chromium compounds (used in metal and dye production), mustard gas (used in research), and silica (used in cosmetics, electronics manufacturing, and metalworking) (American Cancer Society, 2024). Radioactive ores are also another cancer causing agent, used in industries such as mining, oil and gas extraction, and power generation (American Cancer Society, 2024).
Diagnoses and current treatment
In cases that lung cancer is suspected, there are tests that can be done to confirm/deny this suspicion. One such test is an imaging test, which creates pictures of the body to show the location and size of the lung cancer. Some common tests include X-rays, magnetic resonance imaging (MRI), computed tomography (CT) , and positron emission tomography (PET) (Johns Hopkins Medicine, 2024). Another method, sputum cytology, consists of analysing the sputum coughed up from the lungs, in order to identify the presence of cancerous cells (National Cancer Institute, 2024). Finally, you can do a biopsy, which consists of taking a tissue sample for lab analysis. This includes bronchoscopy, in which a tube with a camera is passed through the throat into the lungs to collect tissue; mediastinoscopy, where an incision near the neck provides access to lymph nodes for tissue sampling; and needle biopsy, where a needle is guided by X-ray or CT through the chest to collect lung tissue (Mayo Clinic, 2024).
Once the cancer is identified, there are several different treatment options, depending largely on the type of cancer, stage of the cancer, and the grade of the cancer. Typically, surgery is the first step of treatment as an attempt to remove the tumour. Procedures include wedge resection, which removes a small cancerous section of the lung along with surrounding healthy tissue; segmental resection, which removes a larger portion of the lung while preserving the lobe; lobectomy, which involves removing an entire lobe; and pneumonectomy, which removes the entire lung (American Lung Association, 2024).
Radiation therapy consists of using powerful energy beams in order to kill cancerous cells. In radiation therapy, the patient lies on a table while a machine rotates around the patient, targeting specific areas of the body with radiation. If lung cancer is extensive or has spread, surgery may not be feasible, and radiation therapy might be used as the initial treatment instead. Often, radiation therapy will be combined with chemotherapy (chemoradiation), however this can only happen if the patient is healthy enough (Canadian Cancer Society, 2024).
Chemotherapy consists of the administering of medicine that attacks rapidly dividing cells (a characteristic of cancer cells) throughout the body. It may be administered before surgery to shrink tumours (neoadjuvaant chemotherapy) or to eliminate remaining cancer cells post-surgery (adjuvant therapy). Particularly in advanced stages of canerwhere surgery is not an option, chemotherapy can help stabilise the cancer (American Lung Association, 2024). Unfortunately, chemotherapy can often lead to a lower white blood cell count, making you more susceptible to infection, as well as numerous other side effects including fatigue, hair loss, and nausea (Cleveland Clinic, 2024).
Emerging Advancements in Treatment
Lung cancer treatment is evolving in exciting new ways, and one of the most promising advancements is personalised medicine. Imagine a world where each lung cancer patient receives a treatment plan tailored specifically to their unique genetic makeup. This approach, known as personalised or precision medicine, is not just a dream; it’s already reshaping how doctors treat lung cancer, offering hope for better outcomes and fewer side effects (Herbst et al., 2018).
Traditional lung cancer treatments like chemotherapy and radiation have been effective, but they often come with significant side effects because they are designed to target cancer cells broadly. Personalised medicine, on the other hand, allows doctors to take a deep look at a patient’s cancer on a genetic level and craft a treatment strategy that works best for them. This approach ensures that the treatment targets the exact mutations or abnormalities that are driving the growth of cancer cells (NCI, 2023; Imielinski et al., 2012).
One of the biggest breakthroughs in personalised medicine is the use of targeted therapy. They are drugs that block the growth of cancer by interfering with specific molecules involved in the tumour’s growth and progression. Unlike chemotherapy, which affects both healthy and cancerous cells, targeted therapies are like precision-guided missiles, focusing on specific genetic changes in cancer cells (Mok et al., 2009). Targeted therapies, such as drugs that block tumour growth by interfering with specific molecules, exemplify this approach. For instance, osimertinib is effective against lung cancers with EGFR mutations, showing promising survival improvements (Soria et al., 2018).
Another key aspect of personalised medicine is immunotherapy, which works by helping the body’s immune system recognize and fight cancer cells. Researchers are finding new ways to identify which patients are most likely to benefit from immunotherapy, based on their unique genetic markers (Rizvi et al., 2015; Zhu and Qin, 2024). This means that patients who are likely to respond well can be identified early, avoiding the “trial and error” approach that often comes with traditional treatments (Cancer Research Institute, 2023).
Personalised medicine is making lung cancer treatment more effective and less gruelling for patients, and the future looks even brighter. Researchers are developing advanced genetic testing techniques to identify cancer-driving mutations faster and more accurately (Campbell et al., 2016). With continued research, more people with lung cancer will have access to treatments that are tailored specifically for them, turning a once one-size-fits-all approach into something much more personalised and hopeful.
References
American Cancer Society. (2024). Lung Cancer Risk Factors. Smoking & Lung Cancer | American Cancer Society. https://www.cancer.org/cancer/types/lung-cancer/causes-risks-prevention/risk-factors.html
American Lung Association. (2024). Chemotherapy for lung cancer. Retrieved from https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/treatment/types-of-treatment/chemotherapy.
American Lung Association. (2024). Lung cancer surgery. Retrieved from https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/treatment/types-of-treatment/lung-cancer-surgery.
American Lung Association. (2024). What Causes Lung Cancer. https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/basics/what-causes-lung-cancer
Campbell, J. D., Alexandrov, A., Kim, J., Wala, J., Berger, A. H., & Pedamallu, C. S. (2016). Distinct Patterns of Somatic Genome Alterations in Lung Adenocarcinomas and Squamous Cell Carcinomas. Nature Genetics. https://doi.org/10.1038/ng.3564
Canadian Cancer Society. (2024). Radiation therapy for lung cancer. Retrieved from https://cancer.ca/en/cancer-information/cancer-types/lung/treatment/radiation-therapy
Canadian Cancer Society. (2024). Tobacco control. https://cancer.ca/en/get-involved/advocacy/what-we-are-doing/tobacco-control
Cancer Research Institute. (2023). How Does Immunotherapy Work? https://www.cancerresearch.org/en-us/immunotherapy/what-is-immunotherapy
Centers for Disease Control and Prevention. (2024, October). Lung Cancer Risk Factors. https://www.cdc.gov/lung-cancer/risk-factors/index.html
Cleveland Clinic. (2024). Chemotherapy side effects: Types & management. Retrieved from https://my.clevelandclinic.org/health/articles/10257-chemotherapy-side-effects.
Government of Canada. (2023, June 16). Radon: About. https://www.canada.ca/en/health-canada/services/health-risks-safety/radiation/radon.html
Hecht, S. S. (2012). Lung Carcinogenesis by Tobacco Smoke. International Journal of Cancer, 131(12), 2724–2732. https://doi.org/10.1002/ijc.27816
Herbst, R. S., Morgensztern, D., & Boshoff, C. (2018). The Biology and Management of Non-Small Cell Lung Cancer. Nature, 553(7689), 446–454. https://doi.org/10.1038/nature25183
Imielinski, M., Berger, A. H., Hammerman, P. S., Hernandez, B., Pugh, T. J., & Hodis, E. (2012). Mapping the Hallmarks of Lung Adenocarcinoma with Massively Parallel Sequencing. Cell. https://pubmed.ncbi.nlm.nih.gov/22980975/
Johns Hopkins Medicine. (2024). Lung cancer diagnosis. Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/lung-cancer/lung-cancer-diagnosis.
Lee, J., Saxena, A., & Giaccone, G. (2023). Advancements in small cell lung cancer. Seminars in Cancer Biology, 93, 123–128. https://doi.org/10.1016/j.semcancer.2023.05.008
Mayo Clinic. (2024). Lung cancer: Diagnosis and treatment. Retrieved from https://www.mayoclinic.org/diseases-conditions/lung-cancer/diagnosis-treatment/drc-20374627.
Mok, T. S., Wu, Y. L., Thongprasert, S., Yang, C. H., Chu, D. T., & Saijo, N. (2009). Gefitinib or Carboplatin–Paclitaxel in Pulmonary Adenocarcinoma. New England Journal of Medicine. https://doi.org/10.1056/NEJMoa0810699
National Cancer Institute. (2022, December). Asbestos. https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/asbestos
National Cancer Institute. (2024). Definition of sputum cytology. NCI Dictionary of Cancer Terms. Retrieved from https://www.cancer.gov/publications/dictionaries/cancer-terms/def/sputum-cytology.
National Cancer Institute (NCI). (2023). What is Personalized Cancer Medicine? https://www.cancer.gov/about-cancer/treatment/types/precision-medicine
Nooreldeen, R., & Bach, H. (2021). Current and future development in lung cancer diagnosis. International Journal of Molecular Sciences, 22(16), 8661. https://doi.org/10.3390/ijms22168661
Oliver, A. L. (2022). Lung cancer. Surgical Clinics of North America, 102(3), 335–344. https://doi.org/10.1016/j.suc.2021.12.001
Ragland, L. (2023, April). What Causes Lung Cancer?. WebMD. https://www.webmd.com/lung-cancer/lung-cancer-causes
Rizvi, N. A., Hellmann, M. D., Snyder, A., Kvistborg, P., Makarov, V., & Havel, J. J. (2015). Mutational Landscape Determines Sensitivity to PD-1 Blockade in Non-Small Cell Lung Cancer. Science. https://doi.org/10.1126/science.aaa1348
Simoff, M., Lally, B., & Slade, S. (2013). Author conflict of interest error in: Diagnosis and management of Lung Cancer, 3rd Ed: American College of Chest Physicians Evidence-based Clinical Practice Guidelines. Chest, 144(5), 1743. https://doi.org/10.1378/chest.13-2144
Soria, J. C., Ohe, Y., Vansteenkiste, J., Reungwetwattana, T., Chewaskulyong, B., & Lee, K. H. (2018). Osimertinib in Untreated EGFR-Mutated Advanced Non-Small-Cell Lung Cancer. New England Journal of Medicine. https://doi.org/10.1056/NEJMoa1713137
WorkSafeBC. (2024, October 29). Occupational cancer. https://www.worksafebc.com/en/health-safety/injuries-diseases/occupational-cancer
Zhu, L., & Qin, J. (2024). Predictive biomarkers for immunotherapy response in extensive-stage SCLC. Journal of Cancer Research and Clinical Oncology, 150(1), 22. https://doi.org/10.1007/s00432-023-05544-x