Increasing prevalence of adenocarcinoma of the oesophagus and gastro-oesophageal junction: a study of the Swedish population between 1970 and 1997.

Abstract

To see whether there was an increasing incidence of adenocarcinoma of the oesophagus and gastric cardia in the Swedish population. If there is a rising trend and variations in it can be found, could it be explained as a period or cohort phenomenon? The data were also compared with the incidence of squamous cell carcinoma and gastric cancer with the gastric cardia excluded. Retrospective study. Sweden. Swedish population. Age standardised incidence for each sex was calculated using the age distribution of the world population as a reference. Age-period-cohort models were fitted to data using Poisson regression to model log incidence rates. For the combined group of adenocarcinoma in the oesophagus and gastric cardia age standardised incidence gradually increased during the study period. The median increase between adjacent five-year intervals was 20% in women and 14% in men. A period effect was evident in men. This study shows that the incidence of adenocarcinoma of the oesophagus and gastroesophageal junction is rising for both men and women in the Swedish population. This is explained as a period effect. As well as previously-described risk factors such as gastro-oesophageal reflux, obesity, and smoking, the increasing incidence can be explained as a shift in classification from squamous cell carcinoma to adenocarcinoma after 1985.