Squamous cell carcinoma of the esophagus does not have a highly prevalent predisposing condition, although the incidence increases in persons who have had long-standing exposure to tobacco and alcohol, achalasia, head and neck squamous cell cancer attributable most likely to long-standing alcohol and/or tobacco exposure, tylosis,[4,5] history of lye ingestion, celiac sprue, and, in South America and China, hot liquid ingestion. The etiological role of human papillomavirus infection in squamous cell cancer is under study.[9,10]
Newcastle disease virus (NDV) is a virus that is of interest because it replicates (makes copies of itself) more quickly in human cancer cells than in most normal human cells and because it can kill these host cells (see Question 1).
NDV can be used to directly kill cancer cells, or it can be given as a cancervaccine. Cancer vaccines cause the body's natural immune system to seek out and destroy cancer cells (see Question 4).
The results of clinical trials (research studies with people)...
Efforts at early detection of squamous cell cancer of the esophagus have concentrated on cytological or endoscopic screening of populations in countries where there is a high incidence. Although these programs have demonstrated that it is possible to detect squamous cell cancers in an early asymptomatic stage, no data on efficacy (e.g., mortality reduction) have been published. Esophageal cytological screening studies have been reported from China,[11,12] Iran, South Africa,[14,15] Italy, and Japan. In the United States, such efforts have been focused on individuals perceived to be at higher risk.[18,19] Studies of primary endoscopic screening have been reported from France  and Japan.
Comparisons of both Chinese and U.S. cytological diagnoses with concurrent histological findings showed low (14% to 36%) sensitivities for the cytological detection of biopsy-proven cancers. Specificity ranged from 90% to 99% with a positive predictive value of 23% to 94%. The development of uniform and accurate cytological criteria will require formal cytological-histological correlation studies of esophageal lesions. Such studies should become more feasible with the increasing availability of endoscopy in high-risk populations.
The efficacy of surveillance cytology or endoscopy for high-risk patients with tylosis or long-standing achalasia is not known.
Adenocarcinoma of the Esophagus
Considerable debate has ensued concerning the risk of cancer in patients with Barrett esophagus. Prospective studies have reported annual esophageal cancer incidence rates ranging from 0.2% to 1.9%. Concern over publication bias has led some authors to suggest that the risk may be lower than the literature suggests. A risk of 0.5% per year for development of adenocarcinoma is now thought to be a reasonable estimate for Barrett esophagus.