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About Lung Cancer

About Lung Cancer

Lung cancer occupies the first place in the causes of death from cancer.  “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

Unfortunately, Lung Cancer has a high mortality rate. “One of the main reasons for the high mortality rates consists of the late diagnosis. According to the characteristics of the cancer cells, this malignancy presents itself in two major forms, one being small-cell lung cancer (SCLC), and the other being named non-small-cell lung cancer (NSCLC) according to the histological classification and another rare subtype, lung carcinoid tumor (LCT) tanks as the number one diagnosed type of lung cancer in the oncological field, is further divided into three histologic types: squamous cell carcinoma, large-cell carcinoma, and adenocarcinoma.”. This article will explain what lung cancer is, how it is treated and what patients need to know to prevent its appearance.

The Disease Process

Lung cancer initiates with the cell. Cells are the basic units that form tissues and organs in the body, including the lungs. Under normal conditions, cells divide, forming new cells that replace the damaged or dying ones due to natural aging. However, this process gets out of control sometimes and the cells divide unnecessarily. The damaged cells survive, harming the organ. These abnormal cells replicate and divide uncontrollably as the natural auto-destruction of cells (apoptosis) does not occur. This lack of self-regulation causes an accumulation of harmful cells, forming a tumor benign or malignant (cancer), which could be life-threatening. 

 Once cancer has formed, a part of its cells separates from the tumor and enter the blood vessels and travel to other parts of the body, such as bones, liver, and the brain. Once they have settled somewhere, they multiply and propagate, causing metastasis. 

 What are the Stages of Lung Cancer?

Diagnosis is challenging because cells occasionally do not distinguish between one type and another, hindering classification. Therefore, a tumor sample is necessary for closer scrutiny.

 The stage classifications of lung cancer depend on the advancement of cancerous cells through the body. Tests such as a CT scan (computerized tomography), Positron Emission Tomography (known as PET), Magnetic Resonance Imaging or a tumor biopsy are 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 use 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

 Specialists describe four stages of cancer: I, II, III and IV. Stage I is determined as such at the very first stages of cancer, and stage IV refers to advanced cancer and 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.

Systemic and Local Treatment 

 Doctors differentiate between systemic treatment and local treatment. Systemic treatment applies in the case of advanced and uncontrollable stages. It includes chemotherapy and pharmacological agents that prevent tumor cell multiplication and destroy them. New cancer drugs also prevent tumors’ own blood vessels formation on tumors since these encourage their growth to favor the death of target cells. However, specialists should only applicate drugs once they have determined the adequate target of the tumor cells. At this time, the most notorious target is the mutation of the gene responsible for producing the EGFR protein (‘Epidermis Growth Factor Receptor’).

On the other hand, local treatments target the tumor directly. These include surgery, radiotherapy, and ablation techniques. Doctors prescribe local treatment when the tumor is restricted to a specific zone or area. It is useless to apply local treatment to metastatic cancer. Incorrectly applying local treatment can cause the patient unnecessary harm. Sometimes, doctors choose local treatment to control the symptoms, rather than the disease as a whole.

 Occasionally, medical specialists combine different treatments to control cancer. For example, they indicate systemic treatment after local treatment to reduce the risk of spreading. In the case of small cell lung cancer, the possibility that cancerous cells have disseminated is so high 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, the decision is balanced between the risk to the patient and the benefits it may contribute. Sometimes, the decision to apply one therapy over another is difficult. and requires the opinion of different specialists (oncologists, pathologists, radiologists, thoracic surgeons.)to provide different points of view.

 “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 a significant recent interest in combining RT with immunotherapeutic agents to potentially enhance the abscopal effect.”3

 Does Lung Cancer Have a Cure?

 The cure for lung cancer depends on the stage of the disease and the patient’s general health. Specialists may try a combination of chemo and radiation therapy to completely eradicate cancer. Advanced stages require to keep it under control. Current technologies and techniques are still under development to provide early diagnose for lung cancer.

 Risk Factors

 Even though diverse epidemiological factors cause lung cancer, the most important determinant is tobacco/cigarette smoking. 

 “Although most of the recent epidemiological research has focused on the 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

 Other experts affirm that: “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

 Prevention of lung cancer lies in every person. void smoking or stay away from smokers to avoid exposure to second-hand contamination. While it is true that lung cancer manifest in those that have never smoked, cigarettes 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 genetic tendencies, as well as their cells’ ability to repair damage from oxidation despite smoking cessation.

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

 Given the amount of research and constant development and improvement in treatment, there is hope for anyone diagnosed with this terrible disease. Everyone must collaborate in the prevention of lung cancer, knowing that the damage from tobacco smoke on pulmonary tissue has a cumulative effect and increases with time. If you are already a smoker or passive smoker, check your lungs periodically.

 

References

(1) 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

(2) Simionescu, D., & Simionescu, A. (Eds.). (2017). Physiologic and Pathologic Angiogenesis: Signaling Mechanisms and Targeted Therapy. https://books.google.co.ve/books?id=3PiODwAAQBAJ&pg=PA254&lpg=PA254&dq=lung+cancer+occupies+first+place+in+causes+of+death+from+cancer&source=bl&ots=XCxyOZuqCy&sig=ACfU3U2mAJsUvrikwMpu0jmcZE_AA1ZvpA&hl=es-419&sa=X&ved=2ahUKEwjhrd6Tht7mAhWIjFkKHWjYAxwQ6AEwDXoECAgQAQ#v=onepage&q=lung%20cancer%20occupies%20first%20place%20in%20causes%20of%20death%20from%20cancer&f=false 

(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:

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