Esophageal squamous cell carcinoma remains a leading cause of cancer death worldwide. In 1988, Jaskiewicz et al. determined that mean selenium levels of subjects with premalignant or malignant esophageal cytological changes (54 ng/ml) were significantly (P less than 0.0025) lower than those of subjects without such lesions (68 ng/ml). (20) An inverse relationship was found between selenium status and the degree of cytologic abnormality. These findings suggest that selenium deficiency may play a role in the development of esophageal cancer. The potential value of whole blood selenium determinations and esophageal cytologic examinations in the early detection and of selenium supplementation in the prevention of EC merits further investigation.
In 2004, a nested study from the Nutrition Intervention Trial in Linxian, China, reported significant inverse associations between baseline serum selenium concentration and death from esophageal squamous cell carcinoma (RR= 0.83 (95% CI 0.71, 0.98)) and gastric-cardia cancer [RR= 0.75 (95% CI 0.59, 0.95)] (61) The researchers randomly selected 1103 subjects from the larger trial cohort and followed their health for 15 years. When the subjects were classified by quartile of baseline selenium, those in the highest quartile had a 65% significant reduction in the risk of death from esophageal squamous cell carcinoma (RR= 0.35 (95% CI 0.16, 0.81)) and a 69% significant reduction in the risk of death from gastric-cardia cancer (RR= 0.31 (95% CI 0.11, 0.87)) when compared with the subjects in the lowest quartile.
In 2005, a randomized, controlled intervention trial of selenomethionine 200 mcg daily and/or celecoxib 200 mg twice daily, found selenomethionine to have a protective effect against this form of cancer (94).
In 2006, Lu et al. reported their study of dietary mineral and trace element intake and risk of squamous cell carcinoma of the esophagus (SCCE) in a population- based, case-control study in Taixing, China. (95) A total of 218 SCCE patients and 415 population healthy controls were interviewed using a standard dietary and health questionnaire. The median and quartiles were calculated to represent the average level and distribution of selected dietary minerals and trace elements estimated by the Chinese Standard Tables of Food Composition. The adjusted odds ratios (ORs) comparing the highest with the lowest quartiles were 0.30 (95% confidence intervals, CIs = 0.13-0.67) for selenium intake and 0.28 (95% CI = 0.11-0.70) for zinc intake with obvious dose-dependent patterns (P values for trend = 0.01). The adjusted OR for the combined effect of selenium and zinc intake was 0.53 (95% CI = 0.29-0.96) after controlling for potential confounding factors, including age, gender, educational level, body mass index, and total energy intake. The researchers concluded that our results suggested that the potential joint effect of zinc and selenium might contribute to SCCE risk. Increased dietary intake of selenium and zinc may decrease the risk of SCCE in a low-selenium area of China.
Also, a 2006 review of nutrition in the prevention of esophageal and gastrointestinal by van den Brandt and Goldbohm concluded, Selenium may be inversely related to esophageal and gastric cancer. (96)
These studies are credible evidence of a protective role for selenium against esophageal cancer.