Reading Time:

7 minutes
About Lung Cancer

About Lung Cancer

  We all worry when every media outlet we hear or read about mentions that lung cancer occupies first place in causes of death from cancer. In this article, we will explain exactly what lung cancer is, how it’s treated and what we need to keep in mind in order to prevent its appearance.

  Lung cancer initiates with the cell. A cell is the basic unit that forms tissues and organs in our body, including the lungs. Under normal conditions, cells divide, giving rise to new cells that replace the dying ones suffering from some sort of damage or natural aging. On occasion however, this process of replacing other cells gets out of control and the cells divide without necessity. Even worse, the cells that have suffered damage do not die, rather, they stay alive causing havoc to the organ because they cannot perform any useful function. These abnormal cells continue to replicate and divide without control because they are not being destroyed by a natural process called ‘apoptosis’, which means the auto-destruction of cells. Apoptosis is normal and should happen, otherwise, our cells would just divide ad infinitum!

   This lack of self-regulation causes an accumulation of harmful cells, forming what we call a tumor, which could be benign or malignant. The latter type of tumor is what is called cancer and poses a major threat to the life of the organism suffering from it.

   “Despite multiple treatment options, lung cancer remains the leading cause of cancer death in the United States, with an estimated 224,390 diagnoses and 158,080 deaths projected for 2016. Although roughly 25% of non-small cell lung cancer (NSCLC) diagnoses are stage I, the number of early-stage NSCLC diagnoses is projected to increase, driven by an aging “baby boomer” population and increased low-dose chest computed tomography screening of high-risk individuals, in light of the mortality benefit shown by the National Lung Screening Trial and the ensuing decision to reimburse for screening by the Centers for Medicare and Medicaid Services.”1

   Once cancer has formed, part of the cells that compose it could break away from the tumor and introduce themselves into lymphatic vessels or blood vessels and travel to other parts of the body, such as bones, liver, brain, etc. Once they have settled in somewhere, further multiplication and propagation ensues, giving place to what is called metastasis.

What are the Types of Lung Cancer?

   The challenge in proper diagnosing lies in the fact that the cells do not always show clear distinction between one type and another, making classification more difficult. Therefore, a sample of the tumor is necessary for closer scrutiny.

   The stage classifications of lung cancer depend on how far in the body the cancerous cells have extended. Tests such as a CT scan (computerized tomography), Positron Emission Tomography (known as PET), Magnetic Resonance Imaging or a tumor biopsy are more aggressive forms of testing.

   “For the past 10 years, the International Staging System for Lung Cancer has provided a common language for communication about patients with this disease, and the scientific community has been served well by its application. We have come almost full circle since 1946 when Denoix proposed recommendations for classifying malignant tumors according to tumor-node-metastasis (TNM) descriptions-the concept of stage grouping came later. In the milieu of current research on the biology of lung cancer, the usefulness of specific TNM subsets for clinical research investigations is apparent once again. More specific designations for patient groups may be useful or required for evaluating the implications of molecular components of lung tumors on survival.”2

   There are 4 stages of cancer that are easy to remember: I, II, III and IV. Stage I is determined as such at the very beginning stages of cancer and stage IV refers to very advanced cancer, including metastasis.

   Distinguishing between stages I, II and III depends on the size of the tumor, the degree of influence to the surrounding structures and the condition of the lymphatic ganglia.

What Tools are Available to Fight Lung Cancer?

   When referring to treatment, doctors always differentiate between systemic treatment and local treatment.

   Systemic treatment is applied in the case of advanced and uncontrollable stages of cancer. It is comprised of chemotherapy and new pharmacological agents which act on tumor cells by preventing its multiplication and producing their destruction. New cancer drugs also assist in preventing tumors from forming their own blood vessels (blood vessels help feed tumors and encourage tumor growth) and by acting on the target cells, favoring their death. However, the application of drugs should only be done once the adequate target of the tumor cells have been properly determined. At this time, the most well-known target is the mutation of the gene responsible for producing the EGFR protein which is short for ‘epidermis growth factor receptor’.

   Local treatments are referred to those that target the tumor directly. These treatments include surgery, radiotherapy and other techniques called ablation techniques. The correct indication of a local treatment is established when it is determined that the tumor is restricted to a specific zone or area. It wouldn’t make sense to apply local treatment to a stage of cancer that is generalized (metastasis) and not localized and besides, incorrectly applying local treatment can cause the patient unnecessary harm. Sometimes, local treatment is chosen when doctors are interested in controlling symptoms, rather than the disease as a whole.

   On occasion, medical specialists combine different treatments to help control the cancer. For example, systemic treatment of cancer is indicated after local treatment to reduce the risk that the cancer reproduces. In the case of small cell lung cancer, the possibility that cancerous cells have disseminated is so great that, even though the disease might still be localized, doctors need to apply chemotherapy and radiotherapy, leaving surgery as an alternative in rare cases. In any case, treatment is always decided in a balanced way by assessing the risk to the patient and the benefits it may contribute. Sometimes, the decision to apply one therapy over another are not easy and this is why the opinion of different specialists in the medical field (oncologists, pathologists, radiologists, thoracic surgeons, etc.) are necessary to provide different points of views as far as treatment.

   “In addition to providing effective local treatment at the irradiated tumor site, RT can also mediate an abscopal effect, a phenomenon in which tumor regression occurs in nonirradiated lesions. Although the abscopal effect has been observed for decades, the exact mechanisms underlying this phenomenon remained elusive for much of this time. Demaria and colleagues were the first to link the abscopal effect of RT to an immune-mediated mechanism, and recent studies have provided further evidence that RT has the potential to activate a tumor-directed systemic immune response. With the advent of immunotherapy, new areas of research have emerged, with significant recent interest in combining RT with immunotherapeutic agents to potentially enhance the abscopal effect.” 3

Can Lung Cancer be Cured?

   Lung cancer can be cured depending on the stage of the disease and the patient’s general health. A combination of chemo and radiation therapy can be applied with the intent of complete eradication of cancer. More advanced stages of cancer will necessitate to keep it under control. Current technologies and techniques are still being developed to catch lung cancer early on.

Risk Factors

   Even though there are diverse epidemiological factors that can cause the appearance of lung cancer, by far the most important determinant is tobacco/cigarette smoking.

   “Although most of the recent epidemiological research has focused on effects of short-term exposures, several studies suggest that long-term exposure may be more important in terms of overall public health. The new standards for long-term exposure to PM were originally based primarily on 2 prospective cohort studies, which evaluated the effects of long-term pollution exposure on mortality. Both of these studies have been subjected to much scrutiny, including an extensive independent audit and reanalysis of the original data. The larger of these 2 studies linked individual risk factor and vital status data with national ambient air pollution data.”4

   “Long-term exposure to combustion-related fine particulate air pollution is an important environmental risk factor for cardiopulmonary and lung cancer mortality.”5

How to Avoid Lung Cancer

   The primary responsibility in the prevention of lung cancer lies in every person by simply avoiding smoking or keeping away from those that do smoke, in order to avoid becoming exposed to second-hand contamination. While it’s true that lung cancer can also be diagnosed in those that have never smoked, cigarettes dramatically increase the chances of developing cancer. However, smoking tobacco is not a pre-requisite of pulmonary cancer. The disease can develop depending on each individual’s tendencies at a genetic level as well as their cells ability to repair damage from oxidation despite smoking cessation.

   Given the amount of research and constant improvement on treatment options being developed every day, there is hope for anyone diagnosed with this terrible disease. With this said, it’s important for everyone to do their part, however small, in the prevention of lung cancer, especially when you consider that the damage from tobacco smoke on pulmonary tissue has a cumulative effect and even increases as time goes by.

   “Lung cancer screening programs are a valuable tool in preventive medicine. The data shows that we are seeing benefit and expect as the number of screenings increase, so will the number of early stage cancers diagnosed.”6

 

References

(1) Patterns of Treatment and Outcomes for Definitive Therapy of Early Stage Non-Small Cell Lung Cancer. Kapadia, N. S.M, Valle, L. F., George, J. A., Jagsi, R., D’Amico, T. A., Dexter, E. U., Vigneau, F. D. & Kong, F. Elsevier, 2017. https://www.annalsthoracicsurgery.org/article/S0003-4975(17)30967-0/fulltext

(2) Revisions in the International System for Staging Lung Cancer. Mountain, C. F. Chest Journal. 1997. https://journal.chestnet.org/article/S0012-3692(15)47066-7/fulltext

(3) The Integration of Radiotherapy with Immunotherapy for the Treatment of Non–Small Cell Lung Cancer. Ko, E. C., Raben, D. & Formenti, S. C. Clinical Cancer Research. 2018. http://clincancerres.aacrjournals.org/content/24/23/5792

(4, 5) Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution. Pope III, A., Burnett, R. T., Thun, M. J., et al. JAMA Networks. 2002. https://jamanetwork.com/journals/jama/fullarticle/194704

(6) Lung cancer screenings – winning battles in the lung cancer war. Karim, S. M. Journal of Cancer Science & Therapy. 2018. https://www.omicsonline.org/proceedings/lung-cancer-screenings–winning-battles-in-the-lung-cancer-war-90295.html

 

María Laura Márquez
13 November, 2018

Written by

María Laura Márquez, general doctor graduated from The University of Oriente in 2018, Venezuela. My interests in the world of medicine and science, are focused on surgery and its breakthroughs. Nowadays I practice my profession...read more:

Leave a Reply

If you would also like a response sent to your email please add it in the email box below.