Review Article
Global trends of lung cancer mortality and smoking prevalence Farhad Islami, Lindsey A. Torre, Ahmedin Jemal Surveillance and Health Services Research, American Cancer Society, Atlanta, USA Contributions: (I) Conception and design: All authors; (II) Collection and assembly of data: LA Torre; (III) Data analysis and interpretation: All authors; (IV) Manuscript writing: F Islami; (V) Final approval of manuscript: All authors. Correspondence to: Farhad Islami, MD, PhD. Director, Interventions, Surveillance and Health Services Research, American Cancer Society, 250 Williams Street, Atlanta, GA 30303, USA. Email: [email protected].
Abstract: Lung cancer killed approximately 1,590,000 persons in 2012 and currently is the leading cause of cancer death worldwide. There is large variation in mortality rates across the world in both males and females. This variation follows trend of smoking, as tobacco smoking is responsible for the majority of lung cancer cases. In this article, we present estimated worldwide lung cancer mortality rates in 2012 using the World Health Organization (WHO) GLOBOCAN 2012 and changes in the rates during recent decades in select countries using WHO Mortality Database. We also show smoking prevalence and trends globally and at the regional level. By region, the highest lung cancer mortality rates (per 100,000) in 2012 were in Central and Eastern Europe (47.6) and Eastern Asia (44.8) among males and in Northern America (23.5) and Northern Europe (19.1) among females; the lowest rates were in sub-Saharan Africa in both males (4.4) and females (2.2). The highest smoking prevalence among males is generally in Eastern and South-Eastern Asia and Eastern Europe, and among females is in European countries, followed by Oceania and Northern and Southern America. Many countries, notably high-income countries, have seen a considerable decrease in smoking prevalence in both males and females, but in many other countries there has been little decrease or even an increase in smoking prevalence. Consequently, depending on whether or when smoking prevalence has started to decline, the lung cancer mortality trend is a mixture of decreasing, stable, or increasing. Despite major achievements in tobacco control, with current smoking patterns lung cancer will remain a major cause of death worldwide for several decades. The main priority to reduce the burden of lung cancer is to implement or enforce effective tobacco control policies in order to reduce smoking prevalence in all countries and prevent an increase in smoking in sub-Saharan Africa and women in low- and middle-income countries (LMICs). Keywords: Lung cancer; mortality; smoking; tobacco Submitted Jul 29, 2015. Accepted for publication Aug 6, 2015. doi: 10.3978/j.issn.2218-6751.2015.08.04 View this article at: http://dx.doi.org/10.3978/j.issn.2218-6751.2015.08.04
Introduction Before the start of mass production of tobacco products in the late 19th century, lung cancer was a rare cancer (1). Currently, however, it is the leading cause of cancer deaths in males and the second leading cause in females globally (2). In 2012, lung cancer killed an estimated 1,098,700 men and 491,200 women worldwide, corresponding to 24% and 14% of all cancer deaths in males and females, respectively (2). The most important cause of lung cancer is tobacco
smoking, although the proportion of lung cancer deaths attributable to smoking vary across populations, ranging from >80% in the United States (3) and France (4) to 61% in a pooled analysis of 21 Asian cohorts (5) and 40% in sub-Saharan Africa (6). Lung cancer is also caused by secondhand tobacco smoke, with an estimated 21,400 lung cancer deaths in non-smokers annually (7). Other risk factors for lung cancer include indoor air pollution because of unventilated combustion of coal in the household for heating and cooking (8); outdoor air pollution (9,10);
© Translational lung cancer research. All rights reserved.
www.tlcr.org
Transl Lung Cancer Res 2015;4(4):327-338
328
Islami et al. Global trends of smoking and lung cancer mortality
exposure to hazardous chemicals in some occupations, such as coal gasification and aluminum production (11); exposure to radiation from indoor radon released from soil and building materials (12); and exposure to asbestos, silica dust, and several elements, including arsenic (13). Most of the lung cancer deaths due to secondhand smoke and indoor air pollution occur in low- and middle-income countries (LMICs), particularly China (14,15). In this article, we present estimated worldwide lung cancer mortality rates in 2012. We also show trends of lung cancer mortality during recent decades in select countries in various global regions. Trends in lung cancer mortality rates in a country generally follow historical trends in smoking prevalence, with the trend in lung cancer rates lagging 20-30 years. Therefore, we present contemporary regional smoking prevalence and recent trends in order to provide insights into future lung cancer trends. We do not provide detailed information about the risk factors other than smoking because, except for some specific populations, these risk factors are responsible for a relatively small proportion of lung cancer deaths worldwide (14) and because data on these risk factors are sparse.
included in the above sources (24).
Data sources We used GLOBOCAN 2012 as calculated by the International Agency for Research on Cancer (IARC) to provide estimates of lung cancer mortality rates for all countries worldwide (16). Estimates are generally of higher quality in high-income countries because of higher coverage and quality of death registration (17). We examined temporal trends in lung cancer rates for select countries using the World Health Organization (WHO) Mortality Database (18). All rates were age-standardized to the 1960 Segi world standard population and expressed per 100,000 population (19). We present data for mortality only because there are no substantial differences between incidence and mortality rates and trends, even in economically developed countries, because of poor survival (20). We used the United Nations groupings (with the exception of Cyprus, which is included in Southern Europe for GLOBOCAN) for the classification of the world’s regions (Table 1). Data on smoking prevalence were obtained from The Tobacco Atlas, fifth edition (21), which used estimated data from the Institute for Health Metrics and Evaluation, University of Washington, United States (22), the WHO Report on the Global Tobacco Epidemic 2013 (23), and a national survey with more recent data that were not
© Translational lung cancer research. All rights reserved.
Lung cancer mortality rates in 2012 Lung cancer is the leading cause of cancer death in 87 countries in men and 26 countries in women, with the latter largely confined to high income countries (2). There is large variation in mortality rates across the world in both males and females (Figure 1), with about 30-fold difference in both sexes. Among males, the highest rates (per 100,000) worldwide are found in Hungary (66.6), Armenia (65.6), the Former Yugoslav Republic of Macedonia (63.5), and Serbia (61.8) (Figure 2), whereas the lowest rates are found in Nigeria, Tanzania, and Niger (all
Global trends of lung cancer mortality and smoking prevalence Farhad Islami, Lindsey A. Torre, Ahmedin Jemal Surveillance and Health Services Research, American Cancer Society, Atlanta, USA Contributions: (I) Conception and design: All authors; (II) Collection and assembly of data: LA Torre; (III) Data analysis and interpretation: All authors; (IV) Manuscript writing: F Islami; (V) Final approval of manuscript: All authors. Correspondence to: Farhad Islami, MD, PhD. Director, Interventions, Surveillance and Health Services Research, American Cancer Society, 250 Williams Street, Atlanta, GA 30303, USA. Email: [email protected].
Abstract: Lung cancer killed approximately 1,590,000 persons in 2012 and currently is the leading cause of cancer death worldwide. There is large variation in mortality rates across the world in both males and females. This variation follows trend of smoking, as tobacco smoking is responsible for the majority of lung cancer cases. In this article, we present estimated worldwide lung cancer mortality rates in 2012 using the World Health Organization (WHO) GLOBOCAN 2012 and changes in the rates during recent decades in select countries using WHO Mortality Database. We also show smoking prevalence and trends globally and at the regional level. By region, the highest lung cancer mortality rates (per 100,000) in 2012 were in Central and Eastern Europe (47.6) and Eastern Asia (44.8) among males and in Northern America (23.5) and Northern Europe (19.1) among females; the lowest rates were in sub-Saharan Africa in both males (4.4) and females (2.2). The highest smoking prevalence among males is generally in Eastern and South-Eastern Asia and Eastern Europe, and among females is in European countries, followed by Oceania and Northern and Southern America. Many countries, notably high-income countries, have seen a considerable decrease in smoking prevalence in both males and females, but in many other countries there has been little decrease or even an increase in smoking prevalence. Consequently, depending on whether or when smoking prevalence has started to decline, the lung cancer mortality trend is a mixture of decreasing, stable, or increasing. Despite major achievements in tobacco control, with current smoking patterns lung cancer will remain a major cause of death worldwide for several decades. The main priority to reduce the burden of lung cancer is to implement or enforce effective tobacco control policies in order to reduce smoking prevalence in all countries and prevent an increase in smoking in sub-Saharan Africa and women in low- and middle-income countries (LMICs). Keywords: Lung cancer; mortality; smoking; tobacco Submitted Jul 29, 2015. Accepted for publication Aug 6, 2015. doi: 10.3978/j.issn.2218-6751.2015.08.04 View this article at: http://dx.doi.org/10.3978/j.issn.2218-6751.2015.08.04
Introduction Before the start of mass production of tobacco products in the late 19th century, lung cancer was a rare cancer (1). Currently, however, it is the leading cause of cancer deaths in males and the second leading cause in females globally (2). In 2012, lung cancer killed an estimated 1,098,700 men and 491,200 women worldwide, corresponding to 24% and 14% of all cancer deaths in males and females, respectively (2). The most important cause of lung cancer is tobacco
smoking, although the proportion of lung cancer deaths attributable to smoking vary across populations, ranging from >80% in the United States (3) and France (4) to 61% in a pooled analysis of 21 Asian cohorts (5) and 40% in sub-Saharan Africa (6). Lung cancer is also caused by secondhand tobacco smoke, with an estimated 21,400 lung cancer deaths in non-smokers annually (7). Other risk factors for lung cancer include indoor air pollution because of unventilated combustion of coal in the household for heating and cooking (8); outdoor air pollution (9,10);
© Translational lung cancer research. All rights reserved.
www.tlcr.org
Transl Lung Cancer Res 2015;4(4):327-338
328
Islami et al. Global trends of smoking and lung cancer mortality
exposure to hazardous chemicals in some occupations, such as coal gasification and aluminum production (11); exposure to radiation from indoor radon released from soil and building materials (12); and exposure to asbestos, silica dust, and several elements, including arsenic (13). Most of the lung cancer deaths due to secondhand smoke and indoor air pollution occur in low- and middle-income countries (LMICs), particularly China (14,15). In this article, we present estimated worldwide lung cancer mortality rates in 2012. We also show trends of lung cancer mortality during recent decades in select countries in various global regions. Trends in lung cancer mortality rates in a country generally follow historical trends in smoking prevalence, with the trend in lung cancer rates lagging 20-30 years. Therefore, we present contemporary regional smoking prevalence and recent trends in order to provide insights into future lung cancer trends. We do not provide detailed information about the risk factors other than smoking because, except for some specific populations, these risk factors are responsible for a relatively small proportion of lung cancer deaths worldwide (14) and because data on these risk factors are sparse.
included in the above sources (24).
Data sources We used GLOBOCAN 2012 as calculated by the International Agency for Research on Cancer (IARC) to provide estimates of lung cancer mortality rates for all countries worldwide (16). Estimates are generally of higher quality in high-income countries because of higher coverage and quality of death registration (17). We examined temporal trends in lung cancer rates for select countries using the World Health Organization (WHO) Mortality Database (18). All rates were age-standardized to the 1960 Segi world standard population and expressed per 100,000 population (19). We present data for mortality only because there are no substantial differences between incidence and mortality rates and trends, even in economically developed countries, because of poor survival (20). We used the United Nations groupings (with the exception of Cyprus, which is included in Southern Europe for GLOBOCAN) for the classification of the world’s regions (Table 1). Data on smoking prevalence were obtained from The Tobacco Atlas, fifth edition (21), which used estimated data from the Institute for Health Metrics and Evaluation, University of Washington, United States (22), the WHO Report on the Global Tobacco Epidemic 2013 (23), and a national survey with more recent data that were not
© Translational lung cancer research. All rights reserved.
Lung cancer mortality rates in 2012 Lung cancer is the leading cause of cancer death in 87 countries in men and 26 countries in women, with the latter largely confined to high income countries (2). There is large variation in mortality rates across the world in both males and females (Figure 1), with about 30-fold difference in both sexes. Among males, the highest rates (per 100,000) worldwide are found in Hungary (66.6), Armenia (65.6), the Former Yugoslav Republic of Macedonia (63.5), and Serbia (61.8) (Figure 2), whereas the lowest rates are found in Nigeria, Tanzania, and Niger (all
