Explaining Higher Cancer Rates in Developed Countries
January 17, 2002
Cancer rates, diagnosis and mortality varies widely among developed and developing countries. To understand more about this phenomenon, investigators with the International Agency for Research on Cancer (France) analyzed cancer rates and survival in 11 regions of the world using data from a variety of studies. Researchers analyzed cancer cases diagnosed between 1986 and 1990 among individuals aged 15 or over who were still alive five years later. Based on these, researchers calculated rates and year-specific survival probabilities.
The highest cancer rate is in North America, where 1.5 percent of the population was diagnosed in the previous 5 years and still alive. Western Europe and Japan were 1.2 and 1.0 percent. By contrast, poorer regions of the world such as African, Middle Eastern and South Central Asian were much lower, with rates of approximately 0.2 percent.
- The age group most at risk of cancer is the elderly; thus the cancer rate is higher in developed countries partly because of longer life expectancy.
- Low cancer rates in poor countries are partly due to death from other diseases before people live long enough to experience cancer.
- Less advanced cancer treatments in poor countries means patients are less apt to survive for 5 years.
Mass screening programs account for the largest variation in cancer prevalence between regions due to its effect in raising detection and improving survival. For example, the biggest difference in prostate cancer appeared between China and North America, with the latter experiencing 263 times more cases per 100,000 men.
Source: "Low Cancer Prevalence in Poor Countries Reflects Pre-Existing Low Life Expectancy," Reuters Health, Jan 4, 2002; Paola Pisani, Freddie Bray and D. Maxwell Parkin, "Estimates of the World-Wide Prevalence of Cancer for 25 Sites in the Adult Population," International Journal of Cancer, January 1, 2002.
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