International trends in liver cancer incidence rates.

BACKGROUND Several previous studies have documented region or country-specific liver cancer incidence trends around the world. However, no study has systematically examined the international pattern using the most recently updated incidence data from the International Agency for Research on Cancer. METHODS We examined recent trends in liver cancer incidence rates from 1993 to 2002 by joinpoint analysis for 32 cancer registries worldwide, using Cancer Incidence in Five Continents. We also examined the male to female rate ratios for these and four additional registries, based on the 1998-2002 incidence data. RESULTS Liver cancer incidence rates for both men and women statistically significantly increased from 1993 to 2002 for 8 of 32 cancer registries considered in the analysis. Increases were largely confined to economically developed countries of Western Europe, North America, and Oceania. In contrast, rates decreased in both men and women in 5 registries including 3 in Asia. Despite this, the incidence rates in Asian countries are twice as high as those in Africa and more than four times as high as rates in North America. Male to female rate ratios varied from 0.9 in sub-Saharan African and South American registries to 5.0 in France and Egypt. CONCLUSIONS Liver cancer incidence rates continue to increase in some low-risk parts of the world whereas they are decreasing in some of the highest risk countries in Asia. Etiologic studies are required to further elucidate factors contributing to the divergent liver cancer incidence trends worldwide. IMPACT Our description of international liver cancer incidence trends may stimulate further etiologic studies.