Selenomethionine treatment of certain high-risk patients show promise as protection against the development of esophageal squamous cell cancer (ESCC), according to a report in the September issue of Gastroenterology.
Esophageal squamous cell carcinoma remains a leading cause of cancer death worldwide. Squamous dysplasia, the accepted histological precursor for esophageal squamous cell carcinoma, represents a potentially modifiable intermediate end point for chemoprevention trials in high-risk populations.
While selenium compounds and COX-2 inhibitors have shown potential chemopreventive effects on esophageal carcinogenesis in previous observational studies, such effects had not been evaluated directly in ESCC chemoprevention trials, as pointed out by the authors of the study. Dr. Paul J. Limburg from Mayo Clinic College of Medicine, Rochester, Minnesota and his colleagues now filled this gap by testing the chemoprevention potential of selenomethionine (a synthetic form of organic selenium) and celecoxib (a selective inhibitor of COX-2) in 238 asymptomatic adults with histologically confirmed mild or moderate esophageal squamous dysplasia.
In the overall analysis of the 10-month intervention, neither selenomethionine nor celecoxib significantly changed the dysplasia grade during the course of the trial. However, patients treated with selenomethionine showed a trend toward increased regression and decreased progression, the report indicates, but no such trend was seen with celecoxib treatment.
In a secondary, stratified analysis, treatment of 115 patients with mild dysplasia with selenomethionine was associated with nearly a doubling of the regression rate and halving of the dysplasia progression rate, compared with placebo. No apparent chemopreventive effect was seen in the 123 patients with moderate dysplasia.
The authors conclude that use of celecoxib appears to lack promise but selenomethionine did have a protective effect among subjects with mild esophageal squamous dysplasia at baseline.
Paul J. Limburg, Wenqiang Wei, Dennis J. Ahnen, Youlin Qiao, Ernest T. Hawk, Guoqing Wang, Carol A. Giffen, Guiqi Wang, Mark J. Roth, Ning Lu, Edward L. Korn, Yurong Ma, Kathleen L. Caldwell, Zheiwei Dong, Philip R. Taylor, Sanford M. Dawsey, Randomized, Placebo-Controlled, Esophageal Squamous Cell Cancer Chemoprevention Trial of Selenomethionine and Celecoxib, Gastroenterology, 129 (2005) 863-873.
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