| pubmed-article:17851831 | pubmed:abstractText | Most studies regarding esophageal cancer are based on a selection of patients, influencing the prognosis as well as other variables measured. Sweden may be unique in that it has registries that cover the whole population, permitting population based studies regarding diseases such as esophageal cancer. This also makes it possible to study the true nature of a population of patients and to describe changes in that population over time. | lld:pubmed |
