Canceris among the leading causes of mortality in the contemporary world.The disease occurs following the abnormal growth of different cells.There are many types of tumor that are classified depending on theorgan that they affect. Some of the key risk factors for this type oftumor are smoking, exposure to randon gas, asbestos, and geneticpredisposition (Hanson, Raag, Adrat & Laisaar, 2017). It accountsfor 13 % of all cases of cancer that are diagnosed annually and 19 %of deaths that are attributed to tumors (Center for Disease Controland Prevention, 2016). In this paper, the pathophysiology, clinicalmanifestation, and treatment of lung cancer will be discussed.
Thereare many research projects that have been conducted with the aim ofdetermining the pathophysiology of lung cancer. However, it is stillincompletely understood and complex to many scholars. However,studies have shown that genes that are influenced during thepathogenesis of lung cancer produce proteins that take part in thecell growth as well as differentiation, apoptosis, tumor progression,angiogenesis, and immune regulation (Hanson etal.,2017). The onset of lung cancer is associated with inactivation ofgenes that are responsible for the suppression of tumor. This processis referred to as mutation and it leads to the development ofswellings that culminate in lung cancer. The inactivation of tumorsuppressor genes is attributed to different epigenetic changes,including the modification of histone tail, DNA methylation, andmicro-RNA regulation (Kanaji, Watanabe, Kita, Bandoh, Tadokoro,Ishii, Dobashi & Matsunaga, 2014). This pathophysiology iscommonly observed in different types of small cell lung cancer.
Thesmall-cell lung cancer occurs in the peribronchial areas beforeinfiltrating the bronchial submucosa. A widespread metastasis takesplace in the early stages of the disease. It then starts to spread inthe liver, lymph nodes, adrenal glands, and human brain (Kanaji etal.,2014). The occurrence of a wide range of paraneoplastic syndromes isattributed to the production of peptide hormones. During the processof disease development, an autoimmune phenomenon may occur, leadingto the occurrence of neurologic syndromes, including Lambert-Eatonsyndrome.
Thepathophysiology of non-small cell lung cancer is quite complexbecause each one of them has a different set of processes under whichit develops. For example, adenocarcinoma starts as a pre-malignantlesion that measures five millimeters in diameter (Kumar, 2012).Mutation that leads to the development of adenocarcinoma takes placein the proto-oncogene, which responsible for 10-30 % chances of theoccurrence of this type of lung cancer (Kumar, 2012).
Partof the adenomatous hyperplasia evolves into adenocarcinoma in situ,which develops to form a minimally invasive tumor. Changes that leadto the development of the lung cancer occur in the central airways.The genetic processes that result in the occurrence of non-small cellcarcinomas are associated with different risk factors that areclassified into occupational and environmental agents (Kanaji etal.,2014). The most common environmental factor is smoking, whichaccounts for the largest percentage of cases of lung cancer.
Theclinical manifestation of lung cancer takes place in phases. Thefirst category of clinical features is primary lung lesion signs.They include a cough (reported in 50-70 % of all patients), weightloss, dyspnea, chest pain, and hemopstysis (Wu, Chaudhry & Wong,2016). Coughing occurs when the presence of a mass in the airwaysirritates the cough receptors. In addition, obstruction of thecentral airways by tumors can lead to the development ofpost-obstructive pneumonia as well as distal atelectasis. A rapidloss of weight is attributed to the fact that lung cancer has thecapacity to induce proteolysis and lipolysis, which results in theloss of skeletal muscles and adipose tissues. It also reduces therate at which proteins are synthesized, which contributes towards theloss of weight (Wu, Chaudhry & Wong, 2016). The occurrence ofchest pain is associated with tumors that develop on the pleuralsurface. Moreover, intraluminal as well as extrinsic obstruction ofairways leads to the occurrence of dyspnea in about 25 % of patientswith the lung cancer (Wu, Chaudhry & Wong, 2016).
Thesecond category of symptoms that indicate the clinical manifestationof this type of tumor is mediastinal involvement. The first symptomin this category is superior vena cava syndrome, which is attributedto obstruction of vena cava by the growth (Wu, Chaudhry & Wong,2016). The second symptom is pericardial effusion, which results fromthe infiltration of the tumor into the precardium. The third symptomis preural effusion, which includes dyspnea and chest pain. Thisclinical manifestation may be caused by post-obstructive pneumonitis,lymphatic obstruction, or atelestasis (Wu, Chaudhry & Wong,2016). Fifth, the cancer may manifest through the signs of thepancoast tumor, which include weakness, numbness, atrophy, andshoulder pain.
Thethird category of symptoms through which lung cancer manifests isparaneoplastic syndromes. These are clinical symptoms that are notdirectly attributed to tumor invasion or compression. One of them isthe ectopic Cushing syndrome, which is associated with signs, such ashypertension, muscle weaknesses, and hypokalemia (Wu, Chaudhry &Wong, 2016). The second one is the inappropriate production ofantiduretic hormone, which leads to different symptoms, such asweakness, altered mental status, depression, seizure, and headache.Hypertrophic osteorthropathy is another syndrome that is associatedwith several symptoms, which include digital clubbing, symmetricalarthritis of the wrist, knees, and ankles.
Thekey symptoms that are considered when determining the clinicalmanifestation of this type of cancer can be classified on the basisof regional spread of the tumor and intracranial metastasis. Some ofthe symptoms associated with loco-regional spread of the cancerinclude paralysis of laryngeal nerve, vena cava obstruction, andphrenic nerve palsy (Hanson etal.,2017). Symptoms associated with metastasis spread are the compressionof the spinal cord, bone pain, hepatomegaly, and liver metastasis.These symptoms are considered when diagnosing lung cancer in theclinical settings.
Thereare many options for the treatment of lung cancer, but five of themare quite common. The first one is chemotherapy, which involves theuse of drugs to kill the cancer cells or control their multiplication(Daly, Monjazeb & Kelly, 2015). Some of the most common types ofdrugs that are prescribed by medical oncologists include carboplatin,gemcitabine, docetaxel, vinorelbine, and paclitaxel (Daly, Monjazeb &Kelly, 2015). These drugs have a lot of side effects, such asfatigue, nausea, loss of appetite, infections, and diarrhea.
Thesecond type of treatment is surgery. This is a medical procedure thatentails the complete removal of tumor as well as the nearby lymphnodes, especially those that are located in the chest (Daly, Monjazeb& Kelly, 2015). An effective surgery should involve the removalof tumors together with the surrounding margins of the healthytissues in order to minimize the risk of relapse. The risk ofinfection is the major side effect associated with surgery.
Thethird type of treatment option is radiation therapy. This therapeuticoption involves the application of radiations (including x-rays) tokill the cancer cells (Daly, Monjazeb & Kelly, 2015). Externalbeam radiation is quite common in the health care sector because itis affordable and easy to administer. An effective radiation shouldbe directed to the cancer cells and avoid targeting the healthycells. The CT scan helps oncologists to determine the exact locationof the tumor, thus protecting the healthy cells. Although radiationis effective in the treatment of lung cancer, it is associated withseveral side effects, such as the development of sore throats, lossof appetite, and fatigue.
Fourth,target therapy refers to a treatment option that kills specificproteins and cancer genes. The objective of this type of therapy isto limit the rate at which the cancer cells grow (Daly, Monjazeb &Kelly, 2015). This treatment is preferred because it minimizes therisk of damaging the healthy cells.
Fifth,immunotherapy is used to improve the natural defense of the patients’body. The objective of this type of therapeutic option is to empowerthe body in order to help it fight the cancer cells (Daly, Monjazeb &Kelly, 2015). This requires the use of some drugs, such as nivolumaband pembrolizumab.
Lungcancer is a serious disease that affects parts of the breathingsystem, including the airways located within the lungs. Thepathophysiology of this disease is quite complex, but there areresearchers who have managed to identify that it differs slightly forvarious kinds of lung cancer, including the small-cell tumor andnon-small-cell growths. The development of lung cancer starts whengenes that are influenced during the pathogenesis of this diseaseproduce proteins that contribute towards the development ofdifferentiation, apoptosis, tumor progression, angiogenesis, andimmune regulation. The clinical manifestation of lung cancer takesdifferent forms. Some of the key symptoms that are considered whendiagnosing the cancer include coughing, chest pain, hemoptysis,dyspnea, pericardial effusion, pancoast tumor, and signs associatedwith paraneoplastic syndrome, among others. The diseases can betreated using different therapeutic options that include surgery,immunotherapy, chemotherapy, targeted, and radiation therapy.
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