Scientific Description of the Lung Disease - Term Paper Example

Lung cancer Anna Fihar CONTENT INTRODUCTION 3 SCIENTIFIC OF THE DISEASE 4 SCIENTIFIC EXPLANATION OF HOW IT IS DIAGNOSED 8 OF THERAPY/ TREATMENT/ PREVENTION 9 CONCLUSION 10 REFERENCES: 11 INTRODUCTION Lung cancer is the second most spread cancer among women and men after skin cancer. Statistic from American Cancer Society shows that 228.190 cases of lung cancer were diagnosed in the United States in 2013. Lung cancer causes 159.480 deaths in 2013. Lung cancer did not have such a high prevalence prior to the 1930. But as the rate of smokers increased during last decades lung cancer became quite common disease. Older people are in higher risk, 2 out of 3 people who have lung cancer are 65 years old or older than 65. The average age of people diagnosed with lung cancer is 70. Only 2 % of lung cancer cases were in people younger than 45. For man the possibility of lung cancer development is 1 in 13 and for women is 1 in 16. This statistic includes both smokers and non-smokers. The highest risk for lung cancer development has smokers - 80-90% compared to non-smokers - 10-15% who are passive smoker. Passive smokers are people who inhale smoke from another smoker. Passive smoking causes 3.400 deaths from lung cancer in the United States. The other quite common reason of lung cancer development in the United States is radon gas radiation that generated from radioactive radium. Annually it is leads to 21.000 deaths. It is observed that approximately 1 out of 15 houses in the US have radon level higher than recommended. Air pollution with nitrogen dioxide, sulfate aerosols and other dangerous substances cause 1-2% of lung cancer cases. Genetic inheritance related to polymorphism in chromosomes 5, 6 and 15 provokes 8% of all lung cancer cases. ( American cancer society, 2014) SCIENTIFIC DESCRIPTION OF THE DISEASE Lung cancer defined as a pulmonary carcinoma or carcinoma of the lung. It is associated with abnormal cell growth in the lung tissue that caused by the DNA damage and epigenetic changes. It provokes disorders in cell functioning that include apoptosis or programmed cell death, cell growth or proliferation and DNA repair. Lung cancer divided to two types. They are small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). They differ in cancer cell size and the way of treatment. Figure 1 Types of lung cancer (WebMed,2014) Among all lung cancer non- small lung cancer is the most common one -80-90%. NSCLC divided into 3 subtypes. Squamous cell carcinoma affect squamous cells in the lungs airways. These are flat cells that make an internal layer of the airways. This subtype leads to 20-30% of the NSCLC. Adenocarcinoma affects cells that secrete mucus and peripheral lung tissues. Approximately 40% of lung cancer is adenocarcinoma. Women have higher predisposition to this lung cancer. Large cell carcinoma occur in any parts of the lung and it has tendency to fast growing and spread, that`s why it is harder to treat. It is less spread 10-15% of lung cancer is large cell carcinoma. Pathobiology of NSCLC shows that mutations of the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) are similar in all patients with NSCLC. EGFR is the receptor of the cell surface from the family of the epidermal growth factor. Specific ligands such as epidermal growth factor and transforming growth factor activate EGFR through binding. EGFR plays an important role in cell functioning as control and regulate cell division, angiogenesis, apoptosis and tumor invasion. Mutations in EGFR provoke its activation that lead to the abnormal and uncontrolled cell division. ALK is an enzymes of the cell that encoded by ALK gene.ALK gene can be oncogenic by forming a fusion with other genes. For example, echinoderm microtubule- associatedprotein like-4 (EML4) gene and ALK fusion is related with 3-5% of NSCLC cases, mostly of adenocarcinoma. (Maurie Markman,2014) K-ras proto-oncogene mutations connect with 10-30 % of adenocarcinomas. K-ras proto-oncogene plays the role of tumor suppressor. MAX gene activation observed in small cells lung cancer. This is gene that encodes oncoprotein myc-assosiated X protein (Myc) that involve in cell proliferation, apoptosis and differentiation. Transcription activator BRG1 protein mutations related to lung cancer. Epigenetic changes connected with lung cancer are alteration of micro RNA regulation, DNA methylation and histone tail modification. All these changes damage tumor suppressor genes functioning. For example, in all lung cancer tumors found damaged p53 gene that is tumor suppressor and it controls cell cycle and apoptosis. Small cells lung cancer is quite uncommon and usually it develops only in active smokers. SCLC appears in the bronchi and then spreads throughout the lungs. Also other tumor can develop in lungs such as lung carcinoid tumor that is slow growing tumor that can be removed by surgery. (Romero OA,2013) Both NSCLC and SCLC have several stages that are associated with location of tumors. Early tumors in the lung tissue can stay there for a long time and be undetected. Usually, patients are diagnosed with third or fourth stage of lung cancer. Non- small cell lung cancer has four stages. They first stage is characterized by the existence of tumor only in the specific area of the lung tissue and has not spread to the lymph nodes. Usually patients do not have any symptoms during this stage. First stage can be diagnosed by X-ray or CT scans. Treatment plan for this stage include surgical resection of the tumor. It can be done in a minimally invasive procedure called video – assisted lobectomy. Early detection of lung cancer at this stage and appropriate treatment may help to reduce the risk of further tumor growth and development of the next stages. At the second stage of non – small cells lung cancer genetic faults triggers to further growth of tumor and it spreads into the nearby lymph nodes or the large bronchial tubes. The tumor at the second stage is larger than 5 cm. Patients may have such symptoms as coughing up blood, chest pain and shortness of breath. Treatment may involve surgical resection, radiation therapy or chemotherapy. During third stage cancer spread into the lymph nodes in the middle of the chest. There are two subtypes of third stage of lung cancer. They include stage 3A when tumor is founded only in the lymph nodes of the same part of the chest where it started to growth. During stage 3B cancerous cells spread into the lymph nodes on the opposite part of the chest or above the collar bone. Fourth stage of the lung cancer is the most dangerous one. Tumors are founded in the both lungs, lung fluid and even in other parts of the body such as liver or other organs. In this stage the survival rate of patients is quite low and the mortality rate is the highest one. Patients required appropriate treatment to maintain their life and control the symptoms. (WebMed,2014) Figure 2 Fourth stage of the lung cancer (American cancer society, 2014) SCIENTIFIC EXPLANATION OF HOW IT IS DIAGNOSED Research conducted by UK scientists in seven patients showed that lung cancer can stay in a silent form for more than 20 years. They investigated smokers, non smokers and ex-smokers. After first genetic disorder in the lung tissue the disease can be undetected till new genetic disorder that can provoke rapid growth of cancerous cells. Also, this research proved that first genetic fault was caused by smoking mostly in all diagnosed cases. The research showed that further investigations on development of lung cancer are needed. It will help to detect the lung cancer at early stages and make treatment therapy more successful. (Science Daily, 2014) Diagnostic of lung cancer may include such tests as imaging tests, X-ray image of the lungs can help to detect abnormal mass or nodule; sputum cytology include sputum microscopic analysis for presence of cancer cells; tissue sample or biopsy it is analysis of tissue that contain abnormal cells; positron emission tomography is the modern test that uses tracer radioactive substance and camera to observe organs inside the body; bronchoscopy allow to observe the airways through bronchoscope. Genetic testing is another option to detect lung cancer in patients. It involves testing of genes that are associated with lung cancer such as EGFR and ALK genes. Gene profiling lung tumors is a test that investigates activity of 14 genes and compares them with the same genes in normal cell. (WebMed,2014) DESCRIPTION OF THERAPY/ TREATMENT/ PREVENTION Treatment of the lung cancer depends mostly on the type of cancer. There are several possible types of lung cancer treatment. Palliative care that help patients to improve their health and reduce symptoms connected with lung cancer, Surgery that can help to remove a lobe of the lung with cancerous tissue at early stage of the NSCLC it called lobectomy; segmnetectomy is partial removal of lung part where the cancer developed; a wedge removal of tumor that surrounded by normal lung tissue; radiofrequency ablation uses needle inserted into the tumor to remove cancerous cells with an electrical current. Adjuvant therapy is usually needed after surgical removal of the cancer that helps to prevent it returning. It may be radiation therapy and chemotherapy. (Theodore W Marcy, 2002) Radiation therapy bases on use of the high energy X- rays or other particles that help to damage tumors. For example external- beam radiation therapy uses special machine that produces radiation. It can be used directly for cancerous cells and only in small areas of the body as radiation also destroys normal cells. Radiation therapy as surgery cannot treat widespread cancer. Chemotherapy involves using of drugs that destroy cancer cells through damage of their ability to divide and grow. These drugs may be cisplatin or carboplatin. Usually drugs administered intravenous or by swollen a capsule or pill. Chemotherapy also can damage different body cells such as blood cells, skin cells and nerve cells. That`s why it can be used periodically. CONCLUSION Therefore, lung cancer is quite common cancer worldwide. Smokers are at the highest risk for cancer development. Lung cancer divided to two types that include small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). The most spread is NSCLC and it contain 3 subtypes such as squamous cell carcinoma ,adenocarcinoma, large cell carcinoma. Mutations in EGFR, ALK, K-ras proto-oncogene and MAX gene mostly destroy cell proliferation and apoptosis. p53 is a tumor suppressor that regulate cell cycle is damaged in tumors. Diagnostic of lung cancer include imaging tests,biopsy,bronchoscopy, positron emission tomography and genetic testing. Possible treatments for lung cancer are surgery, chemotherapy and radiation therapy. But it is quite important to investigate genetic testing as it may help to prevent further development of lung cancer through analysis of related genes such as EGFR and ALK genes. Also genetic testing may help to detect predisposition or susceptibility to the lung cancer. (Theodore W Marcy, 2002) REFERENCES: 1. American cancer society. (2014). The key statistics about lung cancer. American Cancer Society Online. Retrieved from http://www.cancer.org/cancer/lungcancer-non-smallcell/detailedguide/non-small-cell-lung-cancer-key-statistics 2. Romero OA.(2013). Researchers discover tumor suppressor gene in very aggressive lung cancer. Science daily Online. Retrieved from http://www.sciencedaily.com/releases/2014/01/140109103648.htm 3. Maurie Markman.(2014). Genetics of Non-Small Cell Lung Cancer. Medscape Online. Retrieved from http://emedicine.medscape.com/article/1689988-overview 4. Theodore W Marcy.(2002). Genetic Testing for Lung Cancer Risk. National Center for Biotechnology Information Online. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1495139/ 5. Science Daily.(2014). Lung cancer can stay hidden for over 20 years. Science Daily Online. Retrieved from http://www.sciencedaily.com/releases/2014/10/141009154007.htm 6. WebMed.(2014). A Visual Guide to Lung Cancer. Web Med Online. Retrieved from http://www.webmd.com/lung-cancer/ss/slideshow-lung-cancer-overview Read More