Epidemiology of esophageal cancer in China.

Chinese historical records of about 2,000 years ago noted several unique epidemiological features and possible risk factors of esophageal cancer in this country. This paper presents selected recent findings on the epidemiology of esophageal cancer in China with special attention directed to geographical distribution, risk factors, and preventive measures. Some of the major characteristics of this disease in China include: 1) an unusually high mortality, the highest in the world; 2) wide geographical differences in mortality; 3) an irregular concentric belt area of elevated mortality; 4) stability of rates over the years; 5) variations in rate by sex; 6) great ethnic differences in mortality; 7) gullet cancer in chickens comparable to the human disease; and 8) associations with high prevalence of epithelial dysplasia of the esophagus. It has been hypothesized that the prevalence of esophageal cancer in high-risk areas may be associated with fermented and moldy foodstuffs, nitrosamines, deficiencies of molybdenum, nutritional deficiencies, specific living habits, and poor oral hygiene. Accordingly, comprehensive studies are being conducted in Lin County and other areas with elevated risk of this diseases so that the possible function of fungi and nitrosamines in the carcinogenesis of esophageal cancer can be determined.