Cancer contributed to 7.6 million deaths worldwide in 2008, and was linked with nearly 170 million years of healthy life lost, according to a study published online Oct. 16 in The Lancet. By 2030, the number of global cancer cases will reach 21.4 million.
Isabelle Soerjomataram, MD, from the International Agency for Research on Cancer in Lyon, France, and colleagues, aimed to improve understanding of fatal outcomes and disabilities related to cancer on a worldwide regional basis. The researchers calculated disability-adjusted life years (DALYs) to estimate the global burden of cancer.
DALYs are comprised of two components. Years of life lost estimates the effects of fatal cancer, while years lived with disability convey the effects of disabling non-fatal disease outcomes (e.g. mastectomy for breast cancer or infertility for cervical cancer).
The researchers analyzed data from cancer registries worldwide to estimate DALYs for 184 countries and 12 world regions.
“While overall DALYs are remarkably similar across different levels of human development, they reflect a higher average premature mortality in lower income countries and a higher average disability and impairment in higher income countries. Our study represents an important first step towards establishing an evidence base for fatal and non-fatal cancer-related outcomes that is urgently needed to set priorities in cancer control,” Soerjomataram said in a press release.
Asia and Europe were the main contributors to the global burden of years of healthy life lost due to cancer, with men in eastern Europe facing the largest cancer burden worldwide (3,146 age-adjusted DALYs lost per 100,000 men). For women, the highest burden was found in sub-Saharan Africa (2,749 age-adjusted DALYs lost per 100,000 women).
Colorectal, lung, breast and prostate cancers were the main contributors to total DALYs rates in most regions, accounting for 18 to 50 percent of the total cancer burden. The contribution of infection-related cancers to the overall DALYs (primarily liver, stomach and cervical cancer) was highest in Sub-Saharan Africa and eastern Asia, at 25 percent and 27 percent, respectively.
Many developing countries face a double burden, as they encounter cancers associated with westernization (breast, colorectal and prostate cancer) as well as infection-related cancers.
The study underscored the fact that improved access to high-quality treatment has not greatly improved survival for a number of common cancers associated with poor prognoses (especially lung, stomach, liver and pancreatic cancers). Thus, primary prevention will need to play a large role if the global cancer burden is to be reduced, according to the researchers.
Soerjomataram and colleagues also noted the importance of combining early detection with adequate and accessible health services in less-developed regions. “For example, patients with localized breast cancer have 17 percent higher survival when diagnosed in more-developed than in less-developed countries.”
The authors concluded, “Our data support the need for better attention to cancer prevention and treatment programmes in low-resource countries, for which our findings have shown the extent of cancer burden in terms of years of life lost and have confirmed the poor prognosis after cancer diagnosis.”