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Lung Cancer
An X-ray scan indicating abnormal mass lesion in the lungs.
SpecialtyOncology
SymptomsPersistent wheezing cough, chest tightness, breathlessness, blood-streaked phlegm, bronchitis, unexplained weightloss
Risk factorsTobacco, asbestos, radon gas
Differential diagnosisSmall cell and Non-small cell carcinoma
TreatmentRadiation therapy, surgery, chemotherapy, and targeted therapy.[1][2]
Deaths9,168 (2018)

Lung Cancer in Australia has killed more than 9,000 people and there are estimated to be over 12,500 new cases as of 2018 [3]. It is the leading cause of cancer death in Australia is responsible for one fifth of cancer diagnosis in Australia [4]. Lung Cancer is differentiated into two different types: Non-small cell lung cancer and small cell-lung cancer [4]. There are a range of diagnostic and treatment options available to treat both disease types. Smoking tobacco cigarettes is considered the leading risk factor of Lung Cancer in Australia, and Government led public health schemes have aimed to reduce smoking and minimise its lung cancer risk [5]. There has been relative success in these campaigns, as survival rates have improved from 9.2% to 17% as of 2014 [4].


Prevalence

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As of 2018, lung cancer remains the leading cause of cancer death in Australia [3]. It is the fifth most common diagnosed cancer in Australia behind breast, prostate, colorectal and skin cancers [3]. There were 9,168 deaths due to lung cancer in 2018, with 5,229 males and 3,969 females. Estimates have also predicted that individuals succumbing to lung cancer by the age of 85 will be 1 in 23, being more likely in men than in women [3]. Lung cancer is more commonly diagnosed within smokers over the age of 60.

Pathophysiology of Lung Cancer

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See also: Lung cancer#Pathogenesis

The onset of lung cancer is due to the uncontrolled growth of cells in the neoplasm of the trachea, bronchi and lungs that eventually metastasise into other regions of the body such as the brain, adrenal glands and liver[6]. Many of the lung cancer deaths in Australia and worldwide are due to metastasis rather than primary, localised tumours [8].

The uncontrolled growth of such cells are influenced by the activation of oncogenes and inactivation of tumour suppressor genes. The inactivation or inactivation of these oncogenes and tumour suppressor genes are due to mutations caused by associated risk factors such as smoking and asbestos. Prevalent oncogenes in the progression of lung cancer include mutations in HER2 and BRAF. Whereas, mutations in the p53 tumour suppressor genes are also said to influence the progression of the disease.

The epidermal growth factor receptor (EGFR) regulates cell proliferation, apoptosis, angiogenesis, and tumor invasion. Mutations and amplification of EGFR are common in non-small-cell lung carcinoma, and they provide the basis for treatment with EGFR-inhibitors. Her2/neu is affected less frequently. Other genes that are often mutated or amplified include c-MET, NKX2-1, LKB1, PIK3CA, and BRAF [needs citation].

Risk Factors

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There are a number of associated risk factors in the onset and progression of lung cancer, however the major contributor is tobacco smoking [7].

Smoking

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Smoking contributes to 90% of lung cancer diagnosis. This is because cigarette and tobacco smoke contain several known carcinogens that alter and damage DNA sequences affecting its ability to proliferate, undergo apoptosis and DNA repair [8]. Carcinogens include benzene, 2-napthylamine, 4-aminobiphenyl, chromium, cadmium, vinyl chloride, ethylene oxide, arsenic, beryllium, nickel and polnium-210 [9]. In addition, nicotine is also an active, toxic component of tobacco smoke that contributes to its addictiveness [9].

Asbestos

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Asbestos are fibrous material that are found in many industrial buildings in Australia from the 1940's to 1987 . Exposure to asbestos occurs through inhalation of the particulates contained in these fibrous material, and they quickly become trapped and deposited in the airways and passages of the lungs [10]. As such, the exposure to asbestos increases the risk of developing cancers in the lung, ovary and pharynx [11]. The incidence of these cancers are said to occur decades after initial exposure to asbestos [10]. Products containing asbestos were eventually phased out towards the end of the 1980's, and a complete ban on asbestos was initiated in 2003. State and Federal Law in Australia have guidelines in their duty of care conduct of both employers and employees to reduce the risk of asbestos exposure [11].

Diagnosis and Treatment of lung cancer

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There are a number of non-invasive diagnostic tools available in Australia to detect lung cancer. These include routine X-Ray, CT and PET scans[4]. In large, these tests aim to determine the extent of tumour growth, its localisation or spread and its staging [x]. Whereas invasive diagnostic tools include a lung biopsy, where a sample of the tumour from lung tissue is extracted and sent for pathological testing to confirm the presence of malignant or non-malignant cells[12]. A sputum cytology analysis may also be requested to further evaluate the presence of malignant cells[4].

Treatment of lung cancer typically depends on the type and stage of the tumours and usually involves surgery, chemotherapy and radiotherapy [13].

Public Health Campaigns in Australia

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Much of the lung cancer deaths in Australia have been attributed to cigarette smoking and many public health schemes have been introduced to increase awareness of the risk of smoking. A number of campaigns have been launched across Australia, most notably QuitNow, which aims to support and encourage Australians to cease smoking[14]. Furthermore, the resources at QuitNow also serve to inform and educate the wider Australian population of the health benefits that cessation has, and guidelines to help families and friends of smokers[15]. In addition, both Federal and State Governments in 2006 initiated schemes that provided graphic health warnings on cigarette packages to curb youth smoking rates[16]. These would often depict the grotesque effects of smoking on the body as a whole, capturing the detrimental effects on the lungs, brain and teeth [x].The campaign also ventured into television advertisements and large public billboards [x] . Cancer Council Australia have also led nation-wide initiatives in the prevention and minimisation of lung cancer. In tandem with state and territory bodies, Cancer Council Australia conduct clinical research to understand the broad mechanisms of lung cancer[17]

Effectiveness of QuitSmoking campaigns in Australia

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The implementation of plain packaging on cigarette packages has seen changing attitudes towards habitual smoking particularly in adolescent and young adult age groups. A study conducted by the Cancer Institute of NSW highlighted that youth support for plain packing of cigarettes increased, with 60% of 12-17 year olds and 67% of 18-24 in favour[18]. The study also mentioned that 1 in 3 teenage smokers aged 12-17, were less likely to continue smoking because of plain packaging[18]. Dunlop and her colleagues also conclude that 41% of teenage smokers tried or thought about quitting as a result of plain packaging on cigarette boxes[18].


See also

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References

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  1. ^ Cite error: The named reference WHO2018 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference TCT2018 was invoked but never defined (see the help page).
  3. ^ a b c d Anonymous (2015-12-18). "Lung cancer statistics". lung-cancer.canceraustralia.gov.au. Retrieved 2019-04-29.
  4. ^ a b c d e Australia, Cancer Council. "The facts on lung cancer: symptoms, causes and more". www.cancer.org.au. Retrieved 2019-04-29.
  5. ^ Statistics, c=AU; o=Commonwealth of Australia; ou=Australian Bureau of (2017-07-26). "Main Features - Lung cancer". www.abs.gov.au. Retrieved 2019-04-29.{{cite web}}: CS1 maint: multiple names: authors list (link)
  6. ^ "Lung Cancer". Cancer Council NSW. Retrieved 2019-05-06.
  7. ^ Australia, Cancer (2015-04-21). "Tobacco". canceraustralia.gov.au. Retrieved 2019-04-29.
  8. ^ Research, The Walter and Eliza Hall Institute of Medical (2014-11-12). "Lung cancer". Walter and Eliza Hall Institute of Medical Research. Retrieved 2019-04-29.
  9. ^ a b Health, Australian Government Department of, Cigarettes and poison, Australian Government Department of Health, retrieved 2019-04-29
  10. ^ a b Ageing, Australian Government Department of Health and, Asbestos-related diseases, Australian Government Department of Health and Ageing, retrieved 2019-04-29
  11. ^ a b www.cancer.org.au https://www.cancer.org.au/preventing-cancer/workplace-cancer/asbestos.html. Retrieved 2019-04-29. {{cite web}}: Missing or empty |title= (help)
  12. ^ Anonymous (2015-12-18). "How is lung cancer diagnosed?". lung-cancer.canceraustralia.gov.au. Retrieved 2019-05-06.
  13. ^ Anonymous (2015-12-18). "Treatment options". lung-cancer.canceraustralia.gov.au. Retrieved 2019-05-06.
  14. ^ Ageing, Australian Government Department of Health and. "Welcome to the Quitnow Website". www.quitnow.gov.au. Retrieved 2019-05-06.
  15. ^ Health, Australian Government Department of. "Quit for your family". www.quitnow.gov.au. Retrieved 2019-05-06.
  16. ^ Health, Australian Government Department of, Health warnings, Australian Government Department of Health, retrieved 2019-05-06
  17. ^ Australia, Cancer Council. "About us - Cancer Council Australia". www.cancer.org.au. Retrieved 2019-05-06.
  18. ^ a b c Dunlop, Sally; Perez, Donna; Dessaix, Anita; Currow, David (2016-11-15). "Australia's plain tobacco packs: anticipated and actual responses among adolescents and young adults 2010–2013". Tobacco Control. 26 (6): 617–626. doi:10.1136/tobaccocontrol-2016-053166. ISSN 0964-4563.