Pattern and Time Trends of Stomach Cancer in Asia from 1950-99.

Background: As there is a lack of data on stomach cancer disease in Asia, the aim of the present study was to examine patterns and time trends for this neoplasm in Asian countries. Methods: A descriptive study was designed to examine the cancer pattern and time trend and to calculate the annual change in mortality and incidence of stomach cancer at 5-year intervals. Data were derived from the WHO Mortality Database, and Cancer Incidence in Five Continents. Results: The highest rates of stomach cancer mortality and incidence (ASR) were observed in Japan, followed by the Republic of Korea, and China, the lowest rates being observed in Thailand. The highest to lowest ratios were 50 and 32 for mortality and 120 and 45 for incidence in males and females, respectively. A decreased trend of mortality was found in all 16 countries where mortality data was available, however, before the decrease, an increased trend was found in Japan in the 1950s and in Sri-Lanka in the 1950-60s. In spite of a significant decrease in mortality nationwide in Japan, an increased trend of stomach cancer incidence was found in Hiroshima (ASR + 7.4 in males and + 1.5 in females for each 5-year period). Discussion: There are very large geographical differences in risk factors of stomach cancer from country to country, and these risk factors are still highly prevalent in specific areas of Asia. Further ecological study with emphasis on host and environmental factors for stomach cancer in Asian countries are strongly recommended.