NEW YORK (Reuters Health) – The incidence of esophageal adenocarcinoma (EAC) is continuing to rise in the U.S. and Australia, although it appears to have plateaued in Sweden, according to a new analysis of registry data.
Researchers say the increase is likely to continue into the future. “Clinicians need to anticipate an increase in the numbers of patients with this potentially fatal cancer,” Dr. Aaron P. Thrift of the Queensland Institute of Medical Research in Brisbane, Australia, who co-authored the new study, told Reuters Health.
Esophageal squamous cell carcinoma, which can largely be attributed to tobacco use and heavy drinking, used to be the most common subtype of esophageal cancer in the industrialized world, Dr. Thrift and his coauthor Dr. D.C. Whiteman noted online July 30 in Annals of Oncology.
But EAC has overtaken it, after a rapid rise in incidence that can be traced back to the early 1970s and continues today.
“The major causes of esophageal adenocarcinoma are gastroesophageal reflux and obesity,” Dr. Thrift noted in an email. “The prevalence of these conditions has increased markedly in recent decades, and this probably explains most of the rise.”
Some recent studies using U.S. and Swedish data have suggested that EAC incidence could be leveling off in these countries. To better characterize the trends, Dr. Thrift and Dr. Whiteman used joinpoint regression analyses and age-period-cohort modeling on cancer registry data for Australia, the U.S., and Sweden from 1984 to 2008.
Overall, EAC rates were twice as high in Australia and the U.S. compared to Sweden. In Australia and Sweden the incidence of EAC was six times higher among men than women, while in the U.S. it was eight times greater among men than women.
In the U.S., the researchers found, EAC incidence among men rose by 7.1% a year from 1984 to 1994, dropping to 1.5% annually from 1994 to 2008.
In Australia, EAC incidence increased by 7.7% annually from 1984 to 1994, and then dropped to 2.2% between 1994 and 2008.
Sweden showed a different pattern, however, with a stable incidence from 1984 to 1993 and a 12.2% annual increase between 1993 and 2001, after which EAC incidence leveled off.
From 1984 to 2008, the incidence of EAC increased by 3.0% annually among Australian women, 4.4% annually among U.S. women, and 5.3% annually among Swedish women.
The authors conclude: “EAC incidence continues to rise among men and women, and while the rate of increase appears to have slowed recently, our observation that age-specific rates continue to increase in successive birth cohorts would suggest that the ‘epidemic’ may be expected to continue for some time yet.”
The increases in EAC are largely preventable, Dr. Thrift noted. “Overweight and obese patients with reflux should be encouraged to lose weight, and to quit smoking if they smoke,” he told Reuters Health. “Overweight or obese men with long-standing reflux might be considered for upper gastrointestinal endoscopy to identify metaplastic or dysplastic changes, particularly if they are smokers.”