Bottom Line: Improved screening and detection efforts, combined with decreases in risk factors like smoking, have reduced the incidence and mortality rates from several common types of cancer in many high-income countries. However, many low-and middle-income countries have seen cancer rates rise, partially due to increases in risk factors that are typical of Western countries.
Journal in Which the Study was Published: Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research
Background: Worldwide, an estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred in 2012, the authors said. Cancer is a leading cause of death worldwide in countries of all income levels, and the number of cancer cases and deaths is expected to grow rapidly as populations grow, age, and adopt lifestyle behaviors that increase cancer risk.
How the Study Was Conducted: Torre and colleagues analyzed incidence and mortality data for the years 2003-2007 from the International Agency for Research on Cancer (IARC) CancerMondial database, which includes incidence data through 2007 from Cancer Incidence in Five Continents, a collaboration between the IARC and the International Association of Cancer Registries, and mortality data through 2012 from the WHO Cancer Mortality database. Study data reflect 50 countries selected to represent various regions of the world.
Results: The authors noted developments across eight major kinds of cancer, which account for 60 percent of total global cases and deaths. The report detailed trends in breast, prostate, colorectal, lung, esophageal, stomach, liver and cervical cancers. The incidence and mortality of many of these cancers have decreased in high-income countries, but risen in low-and middle-income countries due to factors that may include lifestyle changes and lack of appropriate screening or prevention measures.
Author Comment: "This study gives us important clues about the epidemiology of cancer and gives us some ideas about what we could further investigate to improve global public health," Torre said.
Study Limitations: Torre said that the most significant limitation of the study was the variation in reporting standards from one country to the next. For example, she said some nations do not require deaths to be registered, so the mortality data may not be fully representative. Also, data in many countries were collected only in urban centers, which means that cancer incidence and mortality across a whole country's population may not be accurately reflected.
Funding & Disclosures: The study was sponsored by the American Cancer Society. Torre declares no conflicts of interest.
About the American Association for Cancer Research
Founded in 1907, the American Association for Cancer Research (AACR) is the world's oldest and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR membership includes more than 35,000 laboratory, translational, and clinical researchers; population scientists; other health care professionals; and patient advocates residing in 101 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, biology, diagnosis, and treatment of cancer by annually convening more than 30 conferences and educational workshops, the largest of which is the AACR Annual Meeting with almost 19,300 attendees. In addition, the AACR publishes eight prestigious, peer-reviewed scientific journals and a magazine for cancer survivors, patients, and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration, and scientific oversight of team science and individual investigator grants in cancer research that have the potential for near-term patient benefit. The AACR actively communicates with legislators and other policymakers about the value of cancer research and related biomedical science in saving lives from cancer. For more information about the AACR, visit http://www.