A population-based analysis of esophageal and gastric cardia adenocarcinomas in Ontario, Canada: incidence, risk factors, and regional variation

Introduction — In Western countries, the incidence of esophageal adenocarcinoma (EA) and gastric cardia adenocarcinoma (GCA) is increasing. This population-based study describes the incidence of, associated patient risk factors for, and regional variation in EA/GCA in Ontario, Canada.

Methods — All adults with a new diagnosis of EA or GCA between 1972 and 2005 in Ontario were identified. Adjusted annual incidence rates were calculated, and multivariate models were used to identify patient risk factors. Maps were created to explore regional variation.

Results — Over the study period, 8,245 persons were diagnosed with EA/CGA; incidence increased from 1.01 to 3.9 per 100,000. Age (>65 vs. <50 years; rate ratio (RR), 3.4; 95% confidence interval (CI), 2.8-4.1) and comorbidity (highest vs. lowest, RR, 3.5; 95% CI, 2.9-4.2) were most strongly associated with the development of EA/GCA. Considerable regional variation was found in the rates of EA/GCA (North West vs. Central region, RR, 6.5; 95% CI, 4.4-9.6). Maps suggested ethnicity may explain some regional variation, and that the current allocation of designated surgical treatment centres for EA/CGA may be suboptimal.

Conclusions — The incidence of EA/GCA is rising dramatically in Ontario. Further investigation of observed regional variation is warranted, particularly for the allocation of cancer health resources.