Background: This study evaluated the effects of endoscopic mucosa! resection (EMR) on patients with low-grade intraepithelial dysplasia (LGD) of the esophageal squamous cells. Methods: A randomized study recruited 128 LGD patients. These patients were randomly divided into treatment and included 65 LGD cases that were not treated with EMR. Clinical interviews and endoscopy were conducted after 30 months as postoperative follow-up. Results: Concerning the percentages of esophageal lesions that changed from serious conditions into slight conditions (namely from high-grade intraepithelial dysplasia (HGD) to LGD, basal cell hyperplasia, esophagitis and normal mucosa) there was a significantly linear trend relationship between the treatment group and control group. In downstaging of dysplasia grade, the total percentage for the 52 cases (82.5%) in the treatment group was significantly higher than that for the 32 cases (49.2%) in the control group (Pearson X-2 = 15.734, p > 0.001). Also, in patients that remained at the LGD grade or had upstaging of their dysplasia grade, the proportions of the change were significantly different between the two groups. Condusion:The percentage rate of regression of LGD was increased in the EMR treatment group as compared to that of the control group. EMR may prevent or delay the progression of LGD to HGD. (G) 20135. Karger AG, Basel