An international study of three highly lethal gastro-intestinal (GI) malignancies is being conducted among cancer survivors of Hodgkin lymphoma and testis, breast, or cervical cancer that have been reported to population-based cancer registries. Countries participating in this collaboration include Norway, Denmark, Finland, Sweden, the Netherlands, and Canada. The primary aim of the study is to provide new information on the relation between radiation dose and cancer risk for three GI organs (stomach, esophagus, and pancreas), for which few quantitative data exist. In addition, new data will be generated on site-specific age and temporal patterns of radiation-related GI cancers and the possible influence of chemotherapy and other factors.