The rate of esophageal cancer is on the rise worldwide, according to the results of a study published in GUT: An International Journal of Gastroenterology and Hepatology, but the onset and magnitude of the increase varies among countries and even states.
The esophagus is a muscular tube that food and liquids pass through on their on their way to the stomach. Each year in the United States, more than 17,000 people are diagnosed with cancer of the esophagus and more than 15,000 die of the disease.
In an effort to examine rising rates of esophageal cancer and possible causative factors associated with this increase, researchers evaluated data from 117,946 cases of esophageal cancer collected from cancer registries in North America, Europe, Australia, and Asia. The data included esophageal cancers from 1955 through 2009 and was categorized by the number of cases diagnosed per calendar year, the number of cases within age groups (at 5-year intervals), and the number of cases per gender. Overall, 99 percent of cases occurred in patients over the age of 40 and 22.3 percent occurred in women.
The researchers found that the incidence of esophageal cancer increased consistently and dramatically during the study period. The average annual increase ranged depending on location—for example, the average increase was 3.5 percent in Scotland and 8.1 percent in Hawaii. The observed or estimated beginning of the rise in rates was between 1960 and 1990, depending on location. For example, the potential starting point for the rise in rates was 1976 in Denmark and 1991 in Sweden. In general, the calendar period was a more important determinant of incidence than birth cohort.
The rise in esophageal cancer rates was proportionally similar among men and women; however men developed the illness three to six times more frequently overall. In the U.S., rates were seven to nine times higher among men than women.
The researchers noted that there was an abrupt onset in the rise of esophageal cancer rates and speculated that “the epidemic appears to be caused by some exposure that was first introduced around 1950.” There are a variety of known risk factors associated with esophageal cancer, including obesity, acid reflux disease, and infection with H. pylori—however, the results of this study suggest that there is a strong, unidentified causal factor at play. Research will likely continue to focus on identifying potential causative factors for the disease.
Edgren G, Adami HO, Weiderpass E, Nyren O. A global assessment of the oesophageal adenocarcinoma epidemic. GUT: An International Journal of Gastroenterology and Hepatology. Published early online August 23, 2012. doi:10.1136/gutjnl-2012-302412