Overgrowth of an esophageal prosthesis by cancer is a late complication of insertion which presents a difficult management problem. We have treated 14 such patients; 9 had Celestin tubes and 5 Atkinson tubes in situ for a median of 7 months. The median patient age was 75 years; 3 had squamous cell carcinomas and 11 adenocarcinomas; 12 were at the lowest thoracic esophagus or cardia, and 2 were anastomotic. Eleven tubes were overgrown at the top, two at the bottom only, and one at both ends. Dysphagia was graded from 0 to 4 (0 = normal; 4 = dysphagia for liquids). All patients but one improved with treatment. The median pre-treatment grade was 4 (range, 2 to 4) and post-treatment was 2 (0 to 3). This improvement was significant (p < 0.01 Wilcoxon-signed rank). Most patients required only one or two endoscopies. The median survival was 9 weeks from first laser session (range, 3 to 36 weeks). We feel these results justify laser treatment in most patients in whom cancer overgrowth causes blockage of an esophageal prosthesis. (Gastrointest Endosc 1992;38:165-169).