By Susan J. Blumenthal, M.D., Stephanie Safdi, and Yi-An Ko*
There is a killer at large that claims 7.6 million lives each year worldwide. This is a death toll equal to five times the population of Manhattan and higher than the number of deaths from AIDS, tuberculosis, and malaria combined. Is this killer on the FBI's most wanted list?
No, because the enemy is cancer.
World Cancer Day sheds light on the dramatic global impact of cancer, which accounts for 13 percent of annual deaths globally. While most people think of cancer as a disease of aging and affluence, the fact is that in 2005, over 70 percent of cancer deaths occurred in low- and middle-income countries. A striking global gap in cancer mortality exists, with poorer nations carrying the heaviest burden. While revolutionary scientific advances have been made in the industrialized world, transforming our understanding of the causes and treatment of the disease, it remains the case that cancer and other chronic diseases have been largely left off the agenda for developing nations where the focus has been on infectious illnesses. We tend to think of the world as a map with some zones colored by infectious disease and others by chronic disease. This picture, however, is misleading. Cancer demonstrates that infectious and chronic diseases are interrelated. In the developing world, two of the three leading cancers in both men (stomach and liver) and women (cervical and stomach) are caused by preventable infectious illnesses. In fact, 1/5 of all new cancers worldwide are caused by infectious agents such as human papilloma virus (HPV) linked to most cases of cervical cancer, and h.pylori bacteria, which causes stomach cancer.
Cancer is influenced by a complex array of biological, behavioral, environmental and socioeconomic factors. What we call cancer is not a single disease but a collection of more than 100 conditions whose rates differ across population groups and geographic areas. For instance, stomach cancer, the most common cancer in China, causing 412,000 deaths does not even appear on the list of the ten leading causes of mortality in most industrialized nations, including the United States. Furthermore, globally, men and women have different rates of cancer. Among men, the top three cancers are lung, stomach, and liver cancer, while among women the cancers with the highest incidence globally are breast, lung, and stomach. In the United States, differences in health outcomes from cancer are often linked to race and ethnicity. Cancer mortality among African American men, for example, is 38% higher than among white men and 17% higher among African American women compared to Caucasian women. Some disparities in cancer incidence and mortality rates are associated with socioeconomic factors. Poverty is a carcinogen: lower education and income levels are linked to higher rates of the disease. In the United States, as well as other regions of the world, lack of access to health care services, geographic isolation, linguistic and cultural barriers, and racial bias and stereotyping put vulnerable populations at greater risk of developing cancer and distance them from the preventive care, screening, and early treatment that can save lives and reduce health care costs. Local cultural practices connected to poverty can also contribute to the prevalence of cancer. For instance, indoor air pollution from solid fuel use, a common problem in developing country settings, accounts for 1.6 million deaths from lung cancer as well as pneumonia and respiratory disease, resulting in 3.7% of the global burden of disease.
Cancer has environmental links that create higher prevalence of different types of the disease across the globe. Health damaging behaviors contribute 30-50% of the causation of cancer. Increasingly, the Western world is exporting lifestyles with unhealthy diets, tobacco use, and sedentary behavior. In fact, one of the greatest threats to human health that the world has ever known comes from a tiny green leaf. Tobacco, which causes cancers of the lung, throat, mouth, pancreas, bladder, and stomach and increases the risk of cervical cancer, is the single largest preventable cause of cancer worldwide. Approximately 80-90% of all lung cancers and 30% of all cancer deaths in the developing world are linked to tobacco use. Once used primarily by wealthy Westerners, tobacco is today being spread across the globe, often aggressively marketed in low and middle income countries that increasingly face a double burden of both infectious and chronic disease. With one billion people, or 84% of all smokers, now living in the developing world, it is projected that 8 out of every 10 tobacco-related deaths by 2030 will be in developing nations. Furthermore, according to the World Health Organization (WHO), 700 million children (nearly half the world's youth) will breathe air polluted by tobacco smoke in their own homes, exposing them to one of the most dangerous risk factors for cancer.
The impacts of cancer are severe, causing human suffering and robbing nations of people power and economic productivity. Nevertheless, the 2000 Millennium Development Goals neglected to mention the fight against chronic diseases like cancer as a global priority. This is a dangerous omission. Cancer is on the rise worldwide. There is an urgent need to include cancer in the development agenda and enact health policies to reduce risk factors and expand prevention and treatment interventions.
Despite dramatic progress in the fight against cancer in industrialized nations, the elimination of cancer too often seems like an unreachable frontier. Yet imagine the health benefits globally if developed nations such as our own stopped exporting health damaging risk factors like tobacco and fast foods and instead exported solutions like lifesaving prevention programs, treatments, and other advances from scientific research. As the WHO's 2005 Global Cancer Control report conveys, reducing cancer globally, through strengthening health infrastructure, improving cancer control planning, and expanding prevention programs and healthcare access, is a crucial goal. It will require mobilizing the talent, skills, and commitment of public and private sector organizations and establishing new global partnerships and collaborations. In this way, by harnessing the innovation and dedication of all sectors of society, reducing cancer worldwide can be the moonshot of our generation.
* Rear Admiral Susan Blumenthal, M.D. (ret.) is the Distinguished Advisor for Health and Medicine at the Center for the Study of the Presidency in Washington, D.C. and a Clinical Professor at Georgetown and Tufts University Schools of Medicine. For more than 20 years, she served in health leadership positions in the Federal government including as Assistant Surgeon General of the United States and the first Deputy Assistant Secretary of Women's Health within the U.S. Department of Health and Human Services, and as Chief of the Behavioral Medicine and Basic Prevention Research Branch at the National Institutes of Health. Dr. Blumenthal has received numerous awards including honorary doctorates for her contributions to improving global health.
* Stephanie Safdi, a 2005 summa cum laude graduate of Harvard University and Harvard-Cambridge Scholar, serves as Special Assistant to Dr. Blumenthal at the Center for the Study of the Presidency. She holds a Masters Degree from Cambridge University and a previous appointment as a fellow at the Harvard Initiative for Global Health.
* Yi-An Ko, a recent graduate of Harvard University, is a health policy fellow at the Center for the Study of the Presidency.