170 Million Years of Healthy Life Lost to Cancer Worldwide in 2008
The systematic analysis of disability-adjusted life-years (DALYs) for 27 sites of cancer in 184 countries in 12 world regions “used population-based data, mostly from cancer registries, for incidence, mortality, life expectancy, disease duration, and age at onset and death, alongside proportions of patients who were treated and living with sequelae or regarded as cured, to calculate years of life lost and years lived with disability,” noted lead author Dr. Isabelle Soerjomataram, International Agency for Research on Cancer (IARC), Lyon, France.
Based on a country's human development index, which combined indicators of life expectancy, educational attainment, and income, allowing human development to be compared between countries, the investigators then grouped estimates into four categories.
“Worldwide, an estimated 169.3 million years of healthy life were lost because of cancer in 2008,” they found. The primary contributors to total DALYs in most of the world regions were colorectal, lung, breast, and prostate, causing 18% to 50% of the total cancer burden. The contribution of infection-related cancers to the overall DALYs (primarily liver, stomach, and cervical cancer) was high in sub-Saharan Africa (25% of all cancers) and eastern Asia (27% of all cancers), compared to other regions.
Men in Eastern Europe had the largest cancer burden worldwide (3,146 age-adjusted DALYs lost per 100,000 men) and, for women, the highest burden was found in sub-Saharan Africa (2,749 age-adjusted DALYs lost per 100,000 women).
Although the authors noted “substantial global differences in the cancer profile of DALYs by country and region,” the years of life lost “were the most important component of DALYs in all countries and for all cancers, and contributed to more than 90% of the total burden.”
The consistently larger proportions of years of life lost in low vs high human development index countries “indicate substantial inequalities in prognosis after diagnosis, related to degree of human development,” they found.
“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,” said Dr. Soerjomataram. “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.”