Epidemiology of gastric cancer in Chile: I - Case-control study.

The results of a case-control study of stomach cancer carried out with the collaboration of 7 participating hospitals in Santiago, Chile are reported. Patients attending gastroscopy clinics were interviewed before or after gastroscopy. The diagnosis was unknown to either the patient or the interviewer at the time of interview. 360 stomach cancer cases were subsequently matched to non-cancer patients selected from the pool interviewed at the same time as the cases. Study findings show: 1) longer-term residence in high-risk areas in early life by cases than controls; 2) an association between stomach cancer and a prior occupation in agriculture. In a subgroup of 98 cases for whom histologic classification was available, the association with residence in early life in a high-risk area was seen only for cases with intestinal-type stomach cancer.