The Changing Global Burden of Cancer: Transitions in Human Development and Implications for Cancer Prevention and Control

Changes in fertility and life expectancy are leading to major changes in the structure of the global population and, in turn, in the scale of the cancer problem worldwide and at every resource level (WHO 2011b). In addition to the increasing burden of cancer is a changing spectrum of common cancers that is in different regions correlated with levels of human development (Bray and others 2012). The ongoing cancer transition includes a reduction in infection-related cancers (for example, stomach and cervical cancer) that is offset by increases in cancers linked to a Westernization of lifestyle (for example, breast, prostate, and colorectal cancer). The transition also encompasses changes in risk behavior, including tobacco uptake, with a delayed but large impact on the burden from lung and other tobacco-related cancers (Bray and others 2012). The cancer transition is not uniform, however: in Sub-Saharan Africa, recent increases in cervical cancer are observed in Uganda and Zimbabwe; in many countries, a residual burden of cancers associated with infectious agents accompanies the increasing burden of cancers associated with economic transition (Parkin and others 2014). This chapter presents a global overview of the cancer burden, patterns and profiles, recent trends in common cancers, and the expected future scale of the disease by 2030. We link geographical and temporal patterns of cancer to corresponding levels of economic progress to provide an overview of the key characteristics of the global cancer transition. We use gross national income (GNI) per capita as a national indicator of societal as well as economic development (http://data.worldbank.org/news/new-country-classifications), and corresponding rates of cancer incidence and mortality as markers of the extent of the global cancer transition. We draw attention to geographical variations and trends in cancer-specific rates according to differing economic profiles and in each of the world’s regions. In addition, we provide a global, trends-based projection of the likely cancer burden in 2030, based on historical trends refined by incorporating an indicator of level of development. We also examine the number of potentially avoidable new cases and cancer deaths, assuming a reduction in risk factors (Hanley 2001). Even today, tobacco smoking is by far the most important risk factor for cancer (Lim and others 2012). Although the smoking habit is in decline in many high-income countries (HICs), tobacco consumption is still rising in many low- and middle-income countries (LMICs) (Thun and others 2012). As part of the global socioeconomic transition, many countries presently classified as low- or middle-income are increasingly adopting Westernized diets and more sedentary and less physically active lifestyles, leading to a rapid shift in the profile of common cancers in these populations (Bray and others 2012). In view of these developments, this chapter also reviews the main causes of cancer, with an emphasis on the sources of disparities that contribute to an increasingly greater proportional burden from cancer in LMICs, and the prospects for cancer control in different settings. We conclude by pointing to how the high-level political commitment to reduce the rising burden of cancer and other noncommunicable diseases (NCDs) can advance the measurement of cancer to inform cancer control action. There remains an overwhelming need to improve the quality and coverage of population-based cancer registration in most LMICs, as an essential component in planning and evaluating national cancer control activities. This chapter uses the World Health Organization’s (WHO) geographical regions: Africa, the Americas, South-East Asia, Europe, Eastern Mediterranean, and Western Pacific.