Esophageal cancer in migrants from high- or low-risk areas in China.

Death rates from esophageal cancer among migrant and indigenous populations were investigated in three areas in Hubei Province, China. The migrants were from Henan Province. Some came from Xichuam county where esophageal cancer is common and some from Shangchew Prefecture where the disease is less common. Death rates for the migrants moving from high risk to low risk areas over 10 years remained at a high level whereas migrants who have moved from low risk areas to low risk areas for periods in excess of 20 years have remained at a low level. That a small number of chickens raised by migrants from a high risk area developed gullet cancer would suggest the involvement of a traditional dietary habit and an associated carcinogen.