Comparison of Phenotypes and Risk Factors for Esophageal Adenocarcinoma at Present vs Prior Decades

The incidence of esophageal adenocarcinoma (EAC) has increased over the past decades. It is unclear if this increase is the result of a new cancer phenotype or an increase in risk factors for EAC. We aimed to compare risk factors, the proportions of intestinal and nonintestinal phenotypes of EAC, and survival times of patients during the 2009 to 2012 time period vs the 1996 to 1997 time period.

We performed a retrospective single-center cohort study of 829 patients with EAC from the time periods of 1996 to 1997 and 2009 to 2012. Baseline characteristics were compared using χ² analysis for categoric variables and the Student t test for continuous variables. The Cox proportional hazards model was used to compare 5-year survival.

We included 149 patients from the 1996 to 1997 time period and 680 patients from the 2009 to 2012 time period. There was no significant difference between the cohorts in terms of age at cancer presentation, sex, or history of smoking (P > .05). Gastroesophageal reflux symptoms were absent in almost half of the patients from each time period (P = .46). Intestinal metaplasia was identified in esophageal tumor tissues from 48.3% of patients with EAC in the 1996 to 1997 time period and in 49.9% of patients in the 2009 to 2012 time period (P = .45). Patients from each time period presented with similar-stage cancer (P = .25), most at stage III (43% in the 1996-1997 period and 37.8% in the 2009-2012 period). Having EAC during the period of 1996 to1997 was associated with an increased risk of death (hazard ratio, 1.6; 95% CI, 1.3-2.0; P = .001), compared with the 2009 to 2012 time period, in a univariate model (adjusted hazard ratio, 1.7; 95% CI, 1.4-2.1; P < .001) after we controlled for sex, age at diagnosis, tumor stage, and presence of intestinal metaplasia.

In a comparison of patients with EAC from the time periods of 1996 to 1997 vs 2009 to 2012, we found similar and persistent proportions of tumor phenotypes, characterized by a lack of intestinal metaplasia or heartburn symptoms. The lack of symptoms could contribute to our continued inability to identify incident cancers and/or improve patient survival.