Etiology and risk factors for esophageal carcinoma.

Trends toward increasing incidence rates were observed for esophageal and gastric cardia adenocarcinoma in Western countries and were associated with trends toward stabilizing or declining incidence rates for esophageal squamous cell carcinoma, suggesting that these tumors might be associated with distinct risk factors. Overweight and obesity have been consistently related to esophageal adenocarcinoma, but not to squamous cell carcinoma. Body mass index seems to be inversely related to the risk of esophageal squamous cell carcinoma. The influence of obesity on esophageal adenocarcinoma and gastric cardia adenocarcinoma may be related to higher incidence of gastroesophageal reflux in obese persons since the risk of gastroesophageal reflux is strongly related to the risk for Barrett's esophagus. Tobacco smoking is a strong risk factor for esophageal squamous cell carcinoma, but is only a weak risk factor for esophageal adenocarcinoma. Alcohol consumption is a strong risk factor for esophageal squamous cell carcinoma, but is not consistently related to esophageal adenocarcinoma. Selenium, dietary fiber, fruits, vegetables and antioxidants are seen as protective factors. Male gender seems to be a risk factor for both types of tumors in the region, while infection with human papillomavirus does not seem to play a major part in the development of esophageal cancers. Infection with Helicobacter pylori is, however, an interesting factor to this region of tumors as discussed in many reports. It has been suggested that infection with H. pylori is protective to adenocarcinoma, but might be a risk factor for squamous cell carcinoma, although the role of H. pylori in the etiology of these cancers remains somewhat unclear.