Precancerous lesions in two counties of China with contrasting gastric cancer risk

Background Gastric cancer (GC) is one of the most common cancers worldwide and shows remarkable geographical variation even within countries such as C hina. Linqu County in Shandong Province of northeast China has a GC rate th at is 15 times higher than that of Cangshan County in Shandong, even though these counties are within 200 miles of each other. Method In order to evaluate the frequency of precancerous gastric lesions i n Linqu and Cangshan Counties we examined 3400 adults in Linqu County and 2 24 adults in Cangshan County. An endoscopic examination with four biopsies was performed in each individual of the two populations. Results The prevalence of intestinal metaplasia (IM) and dysplasia (DYS) wa s 30% and 15.1%, respectively, in Linqu compared to 7.9% and 5.6% in Cangsh an (P < 0.01). Within these histological categories, advanced grades were f ound more often in Linqu than in Cangshan. The prevalences of IM and DYS we re more common at each biopsy site in Linqu, where the lesions also tended to affect multiple sites. Conclusions The findings of this study support the concept that LM and DYS are closely correlated with risks of GC and represent late stages in the mu ltistep process of gastric carcinogenesis.