[661] Squamous Metaplasia in Residual Esophageal Adenocarcinoma after Chemoradiation

Matthew B Elkins, Barbara McKenna. University of Michigan Health Systems, Ann Arbor, MI

Background: Esophageal adenocarcinoma is a tumor with increasing incidence world-wide, with approximately 460,000 new cases a year, and a less than 15% 5-year survival rate. In the past, the standard of care for esophageal adenocarcinoma was pre-operative staging followed by esophageal resection. More recently, pre-operative chemoradiation has been added in an effort to decrease the rate of recurrence. Chemoradiation alone has been suggested for treatment of esophageal adenocarcinoma in patients who are unable to undergo an esophageal resection. These patients are monitored with regular endoscopic biopsies for recurrence. Interpretation of follow-up biopsies after chemoradiation, with or without resection, must take into account the changes within epithelium in response to chemoradiation. This therapy results in squamous metaplasia of the surface epithelium, the cells lining the esophageal gland ducts, residual Barrett's mucosa, and deep glands. Previous studies have not evaluated the presence of squamous metaplasia within residual invasive adenocarcinoma.
Design: We evaluated 52 esophageal resections with pre-operative adjuvant chemoradiation for residual adenocarcinoma, Barrett's mucosa, and squamous metaplasia. Squamous metaplasia identified within residual carcinomatous glands was scored for focal, moderate, or diffuse involvement of the glands.
Results: Of the 52 specimens examined, 23% showed squamous metaplasia not only within residual Barrett's mucosa but also within nests of invasive adenocarcinoma; 15% focally, 6% moderately, and 2% diffusely.
Conclusions: Deep nests of squamous cells in biopsies from patients treated for esophageal adenocarcinoma are most likely squamous metaplasia in esophageal gland ducts or in residual Barrett's glands. However, residual nests of adenocarcinoma may also undergo squamous metaplasia which may obscure the residual adenocarcinoma or may be misinterpreted as invasive squamous cell carcinoma.
Category: Gastrointestinal

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 62, Wednesday Morning


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