Abstract
BACKGROUND: The increasing incidence of esophageal and proximal gastric (cardia) adenocarcinoma and the decreasing incidence of distal gastric (antropyloric) adenocarcinoma has been documented in several populations. The aim of the present study was to examine incidence trends of these neoplasms in Ontario, Canada’s most populous province, over a 39-year period.METHODS: Analyses were based on data obtained from the Ontario Cancer Registry of Cancer Care Ontario. Number of cases and rates per 100,000, age-adjusted to the 1996 Canadian standard, were obtained for all esophageal and gastric carcinoma cases reported between 1964 and 2002. Rates were grouped into five-year periods to analyze trends over the 39-year period. Point and 95% CI estimates of average annual percentage change in incidence rates were calculated with a log-linear regression model.RESULTS: The incidence of adenocarcinoma of the distal esophagus increased in men and women (average annual increase of 9.5% in men; 4.3% in women). The incidence of adenocarcinoma of the cardia increased in men and women (average annual increase of 7.3% in men; 5.8% in women). The incidence of antropyloric adenocarcinoma increased in men and women (average annual increase of 4.4% in men; 5.3% in women). The incidence of esophageal squamous cell carcinoma remained stable.CONCLUSIONS: There has been a significant increase in the incidence of adenocarcinoma around the gastroesophageal junction in men over the 39-year study period. The increase in incidence of distal gastric adenocarcinoma is unexpected and may relate to a reclassification phenomenon, immigration trends in Ontario and a rising incidence of diffuse/signet ring cell adenocarcinoma.