Editorial

Lung cancer was assumed rare disease; now it’s considered a public health problem [1]. It’s the most common cancer worldwide; there are more than 1.3 million new cases every year [1,2]. It’s the first ranked cancer in both sexes and in males [2,3], and the fourth in females. It constitutes 13.0% of all cancers in both sexes. Fifty five percent of the lung cancer cases occur in the developing countries [2].

In Egypt, lung cancer is one of the most common cancers, 5.0%-7.0% of all cancers [4]. It’s incidence increased during 1980-2014 [5], from 11.9 to 63.3/100.000 populations for men and from 3.7 to 13.8/100.000 populations for women [1,6,7]. Lung cancer ranks the fifth in males and both sexes, and ninth among females [3]. Also, lung cancer is a leading cause of death (25.0% of all cancer deaths); ranks first in males and second in females [2]. Mortality rate increased from 9.1 to 32.4/100.000 populations and from 2.3 to 12.4/100.000 populations, between 2010 and 2014, among males and females, respectively [1,7]. While, clear reduction regarding lung cancer mortality was reported in developed countries [5].

Lung cancer occurs in four major histopathological types; adenocarcinoma, squamous cell carcinoma (SCC), large cell carcinoma (LCC), and small cell carcinoma [8]. In Egypt, the commonest types are SCC (31.7%), adenocarcinoma (30.9%), and LCC (26.0%) [9].

The significant and independently associated with marked increase of lung cancer risk are old age, male sex, and smoking [10].

The median age of lung cancer patients, in developed countries, is 60 years [6]. In Egypt, mean age of cancer patients is 48 years [11]. Most of lung cancer patients in Egypt were in the fifth (55.3%) and sixth (29.3%) decades [9].

Males have higher lung cancer incidence rates than females worldwide; 3:1 [2,12]. In Egypt, male to female ratio is 3.2:1 [9,11]. However, lung cancer rates in women have been raised because of increased numbers of women smokers [2].

Urban residence is risk factor; in Egypt urban to rural residence ratio is 2.1:1 [9]. This attributed to tobacco smoking, air pollution, and type of occupation.

Smoking is the most common lung cancer risk factor [12], almost all cases are attributed to active (80.0%) and passive (5.0%) cigarette smoking [2]. It’s the main risk factor in Egyptian patients [6], 93.5% of them were smokers [9].

Air pollution (car exhaust) and occupational exposure as asbestos and arsenic are important risk factors [2]. In Egypt, 47.2% of the patients were workers in cement construction and production [9]. Environmental pollution is among the most common risk factors [12]. Evidences confirm an association between constituents of ambient air pollution and increased lung cancer mortality [13]. Nitrogen oxides (a measure of air pollution specific to traffic) were reported as significant risk of lung cancer [14]. In developing countries indoor air contamination is resulting from use of unprocessed solid fuels for cooking and heating [15]. Smoky coal was a major determinant of lung cancer. Also, radiation plays a role e.g. radium miners, radon gas, etc. [2].

Chronic inflammation and chronic obstructive pulmonary disease are associated with increased risk of lung cancer [2].

Genetic factors play a significant role in lung cancer susceptibility [10]. Positive family history of lung cancer is useful risk indicator [16]. Five single nucleotide polymorphisms (SNPs) were associated with high susceptibility to lung cancer [10]. Genetic susceptibility; SNPs has confirmed in CYP1A1 m1 and m² [17], while family history of malignancies was present among 9.8% of patients [9].

Physical inactivity is associated with increased risk of lung cancer [18]. Also, evidence indicated low consumption of fruits, vegetables [15] and dietary antioxidants [2] are associated with high lung cancer risk.

Incidence and mortality patterns of lung cancer are parallel. In developed countries, advanced technology and awareness have resulted decrease the lung cancer mortality. But, in developing countries as Egypt, much efficient procedures are required [5]. Cancer registration is required for enabling strategic planning for prevention, treatment, and control [3]. Lung cancer screening is recommended [14], however, early detection using chest X-ray, sputum cytology, and CT scans are not supportive for routine mass screening [1]. Decreases in smoking have manifested as decline lung cancer incidence rates [2].

References

1. Larbi ABID (2011) Lung cancer around the world and Arab countries. AMAAC Workshop, Algiers 19.
2. El-Bolkainy MN, Nouh MA, El-Bolkainy TN, Badawy OM (2016)  Epidemiology of cancer. Pathology of Cancer PP: 978-977.
3. Ferlay J, Shin HR, Bray F, Soerjomataram I, Dikshit R, et al. (2010) GLOBOCAN 2008 v1.2, Cancer incidence and mortality worldwide: IARC Cancer Base No. 10.  Lyon, France.
4. Ibrahim AS, Khaled HM, Mikhail NNH, Baraka H, Kamel J, et al. (2014) Cancer incidence in Egypt: results of the National Population-Based Cancer Registry Program. J Cancer Epidemiol ID: 437971.
5. Dubey AK, Gupta U, Jain S (2016) Epidemiology of lung cancer and approaches for its prediction: a systematic review and analysis. Chin J Cancer 35: 71.
6. Ferlay J, Soerjomataram I, Dikshit R, Eser S, Mathers C, et al. (2015) Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN 2012. Int J Cancer 136: E359-386.
7. Freedman LS, Edwards BK, Ries LAG, Young JL (2006) Cancer incidence in four member countries (Cyprus, Egypt, Israel, and Jordan) of the Middle East cancer consortium (MECC) compared with US SEER.
8. Khuder SA (2001) Effect of cigarette smoking on major histological types of lung cancer: a meta-analysis. Lung Cancer 31: 139-148.
9. Abo-Elkheir OI, Hafez MR (2018) Characteristics, risk factors and histopathological types of bronchogenic carcinoma amon cases presented to Chest Department, Al-Zahraa Hospital, Al-Azhar University. Int J Community Med Public Health 5: 1281-1290.
10. Heuvers ME, Van den Hondel KE, Van Klaveren RJ (2011) Genetic risk factors for lung cancer in the Rotterdam Study. Proc Am Thorac Soc 8.
11. https://www.nci.cu.edu.eg/Statistics.aspx
12. Urman A, Josyula S, Rosenberg A, Lounsbury D, Rohan T, et al. (2016) Burden of lung cancer and associated risk factors in Africa by region. J Pulm Respir Med 6: 3.
13. Hales S, Blakely T, Woodward A (2012) Air pollution and mortality in New Zealand: cohort study. J Epidemiol Community Health 66: 468-473.
14. Kauczor HU, Bonomo L, Gaga M, Nackaerts K, Peled N, et al. (2015) ESR/ERS white paper on lung cancer screening. Eur Respir J 46: 28-39.
15. WCRF (2007) Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Washington, DC: World Cancer Research Fund/American Institute for Cancer Research.
16. Lissowska J, Foretova L, Dabek J, Zaridze D, Dabrowska NS, et al. (2010) Family history and lung cancer risk: international multicentre case-control study in Eastern and Central Europe and meta-analyses. Cancer Causes Control 21: 1091-1104.
17. Hussein AG, Pasha HF, El-Shahat HM, Gad DM, Toam MM, et al. (2014) CYP1A1 gene polymorphisms and smoking status as modifier factors for lung cancer risk. Gene 541: 26-30.
18. Tardon A, Lee WJ, Delgado RM, Dosemeci M, Albaneset D, et al. (2005) Leisure time physical activity and lung cancer: a meta-analysis. Cancer Causes Control 16: 389-397.