Cancer Screening in the Developing World: Case Studies and Strategies from the Field

Worldwide, cancer is responsible for one in eight deaths—more than AIDS, tuberculosis, and malaria combined. This global burden starkly illustrates the inequality between the developed and the developing world. While the majority of people living in developed countries receive timely treatment, those living in developing countries are not as fortunate and their survival rates are much lower—not only due to delays in diagnosis, but also to a lack of personnel, a paucity of treatment facilities, and the unavailability of many medications. Routine screening—a mainstay in the developed world—could greatly increase the likelihood of identifying individuals with early stage cancers and thus reduce the number of people who present with advanced disease. This book represents a critical addition to the literature of global health studies. Focusing on cervical, breast, and oral cancers, these case studies highlight innovative strategies in cancer screening in a diverse array of developing countries. The authors discuss common issues and share how obstacles—medical, economic, legal, social, and psychological—were addressed or overcome in specific settings. Each chapter offers an empirical discussion of the nature and scope of a screening program, the methodology used, and its findings, along with a candid discussion of challenges and limitations and suggestions for future efforts.

• Language: English
• Publisher: Dartmouth College Press
• Release date: May 1, 2018
• ISBN: 9781512602524

Book preview

2012;55:S95–10.

Chapter 1

Madelon L. Finkel

Global Burden of Disease

A Short Overview

The world has been undergoing a major shift over the past few decades in the incidence and prevalence of diseases as well as in the leading causes of death. Diseases that once were highly prevalent (and usually deadly) are no longer so, and diseases that were not prevalent in the past are now at the top of the list. Whereas for many decades infectious disease morbidity and mortality was the prime focus of concern, especially in the developing world, today chronic, non-communicable diseases (NCDs) are.

Quantifying the global burden of disease is challenging at best. The World Health Organization (WHO) arrived at a broad consensus definition of global burden of disease (GBD) in the mid-1990s to reflect the collective disease burden produced by all diseases around the world. (1) In an effort to define the concept more specifically, the WHO uses the disability-adjusted life year (DALY) to measure burden of disease. The DALY was developed in the 1990s as a way of comparing overall health and life expectancy among different countries. Essentially, it is a measure of overall disease burden expressed as the number of years lost due to ill-health, disability, or early death, and years of life lost due to time lived in states of less than full health or years of healthy life lost due to disability. However, obtaining accurate, valid statistics from countries is difficult, and in some cases almost impossible. Because so many factors have an impact on disease, political, social, and economic determinants of health must be taken into account, and these factors vary widely not only among countries, but also within them.

Almost all of the data presented in this chapter are abstracted from The Global Burden of Disease Study 2015 (GBD 2015), a comprehensive, worldwide observational epidemiological study that assesses mortality and disability from major diseases, injuries, and risk factors. The study relies on more than 80,000 data sources, drawing from the world’s largest global health database and focusing on 125 countries and 3 territories. Almost 2,000 collaborators contributed to the reports. (2)

The GBD studies examine trends from 1990 to the present and make comparisons across populations. The GBD project, initially sponsored by the World Bank and conducted by the WHO, presents a historical, comprehensive look at changing morbidity and mortality patterns worldwide from 1990 to 2015. The GBD 2015 is the most recent in the series. The studies provide a comprehensive, global estimate of death and disease by age, sex, and country. Based on the GBD statistics, it is apparent that the world is experiencing an epidemiological/demographic transition. There has been a noticeable shift in global deaths and disability in recent decades; overall, life expectancy is rising in most parts of the world. This chapter presents a broad overview of the GBD, including disease prevalence, incidence, and mortality in the developed and developing world.

The Demographic Transition and Its Effects on Mortality and Life Expectancy

Over the past couple of centuries the world experienced a demographic transition characterized by a transition from high birth and death rates to lower birth and death rates. The Demographic Transition Model describes a process that began in Europe in the early 1800s, characterized by decreases in mortality followed, usually after a time lag, by decreases in fertility. (3) Under this model, initially both birth and death rates are high and natural population growth is low. As mortality begins to fall, fertility still remains high. As fertility begins to fall, there is a reduction in birthrates, eventually resulting in a reduction in the rate of population growth.

Somewhat simplistically, there is a transition from high birth and death rates to lower birth and death rates primarily because of advances in medicine, hygiene, public health, and economics. Reductions in mortality and birthrates reduce population growth, accelerate human capital formation, and increase income per capita. Demographers have shown a strong link between number of live births, infant mortality, and women’s education. (4) Further, reductions in the birthrate are closely linked to higher labor force participation rates among women. (5) The end result is that life expectancy increases and premature death, notably infant and child mortality, decreases.

Worldwide, people are living much longer today than they were even two decades ago. Overall, life expectancy was 71.4 years in 2015, with an average life expectancy for women of 73.8 years and 69.1 years for men. From 2000 to 2015 global average life expectancy increased by 5 years, primarily as a result of improvements in child survival and expanded access to antiretrovirals for treatment of HIV. (6) Of course these estimates must be interpreted with caution, especially given recent geopolitical events such as forced migration, wars, famine, and drought that jeopardize gains made in life expectancy around the world.

Reflecting the trend in increased life expectancy, country age pyramids in the twenty-first century look quite different from those in the twentieth century. Whereas most places in the developed world have an aging population (the United States, Europe, and Australia in particular), countries in the developing world have a surging younger population as well as an aging population. Although gains in life expectancy have been shown for almost all countries, there is substantial variation within and across countries. Overall, Monaco leads the list of countries with the highest life expectancy, 89.5 years, with Japan second, at 85 years. In stark contrast, Chad posts the lowest life expectancy (49.8 years). (7) Within countries there are substantial differences in life expectancy. For example, in 2014 in the United States, life expectancy for Caucasians was 79.1 years, compared to 75.5 years for African Americans and 82.9 years for Hispanics. There are also substantial variations by gender, and Hispanic women and men have the highest life expectancy among ethnic groups in the United States. (8)

Changing Patterns in Mortality

The GBD 2015 shows global changes in deaths in adults and children. While the number of deaths and age-standardized death rates for communicable diseases fell between 1990 and 2015, there was an increase in age-standardized death rates for diabetes, atrial fibrillation and flutter, some cancers (such as pancreatic), drug use disorders, cirrhosis, and chronic kidney disease. In particular, drug use disorders and chronic kidney disease account for the largest percent increase in premature