Various research studies causally associate lung cancer with active and passive smoking , a variety of occupational agents , and indoor and outdoor air pollution .
The chances of getting lung cancer has increased with increase in household air pollution ( 11 , 12 ) . Only 1 out of 10 patients diagnosed with lung cancer will survive the following 5 years ( 13 ) . It has been noticed that smoking prevalence has declined in many developed countries ( 14 ) however ; it is increasing in developing countries and also among women ( 15 ) . In developing countries lung cancer is usually detected at an advanced stage ( 16 , 17 ) and this puts a greater economic impact on middle- or low-income families . Lung cancer has multiple risk factors , which are combination of the genetic and external factors ( environmental & occupational ) and the proportion of lung cancer cases attributable to preventable risk factors vary greatly across countries ( 18 , 19 ) . The resulting evidence from various research studies , causally associate lung cancer with active and passive smoking , a variety of occupational agents , and indoor and outdoor air pollution ( 20 ) .
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