Effectiveness of Vitamin C Solution in Reducing Adverse Reactions Caused by Painless Lugol Chromoendoscopy

Goal: The purpose of this study was to evaluate the effectiveness of vitamin C solution (VCS) in reducing adverse reactions caused by painless Lugol chromoendoscopy. Background: Lugol chromoendoscopy is an effective method for screening superficial esophageal squamous cell carcinoma, although Lugol iodine solution (LIS) causes mucosal irritation. Study: In 4 hospitals in China, patients were randomized and divided into a distilled water (DW) group, an sodium thiosulfate solution (STS) group and a VCS group. Patients’ esophageal mucosal surfaces were stained with either 1.2% or 0.5% LIS and then sprayed with DW, STS, or VCS at various concentrations. For the current randomized study, 1610 patients were enrolled in the 1.2% LIS group and 1355 patients were enrolled in the 0.5% LIS group. In addition, 150 patients were enrolled to assess the discoloration effect. The primary outcome for evaluation was the incidence of acute or late adverse reactions after Lugol iodine staining. The secondary outcome for evaluation was the discoloration effect on esophageal iodine-stained mucosa. Results: VCS significantly reduced the occurrence of acute adverse reactions due to staining from 1.2% LIS. The effect of VCS was similar to that of STS but better than that of DW ( P <0.05). Regarding 0.5% LIS staining, VCS reduced the incidence of acute adverse reactions and heartburn within 1 week ( P <0.05). Both VCS and STS had similar effects. In addition, compared with spraying NS, VCS caused rapid decolorization of iodine-stained esophageal mucosa. After 120 seconds of deiodination, the color of the esophageal mucosa faded by 90%, which is similar to the results seen in the STS group. This contrasts with the results seen in the DW group, which showed fading by only 50.97% ( P <0.05). Conclusion: VCS can effectively reduce adverse reactions caused by different concentrations of LIS, indicating its important clinical application in the screening of superficial esophageal squamous cell carcinoma.