Sodium thiosulfate solution spray for relief of irritation caused by Lugol's stain in chromoendoscopy

Background: Mucosal iodine staining is known to improve the endoscopic visualization of esophageal squamous dysplasia and cancer. However, it often causes mucosal irritation leading to retrosternal discomfort. The clinical usefulness of sodium thiosulfate solution (STS) for easing symptoms induced by mucosal staining with Lugol's solution was evaluated in this study. Methods: One hundred twenty healthy men over 50 years of age were enrolled in the study. They each underwent esophagogastroscopy including the spraying of Lugol's iodine solution (10 mL) on the mid and distal esophagus and were subsequently randomized into three groups: (I) no treatment (n = 40), (11) spraying of 20 mL of aluminum-magnesium hydroxide gel (Maalox) by means of endoscopic catheter (0 = 40), and (III) spraying of 20 mt of 5% sodium thiosulfate solution by means of endoscopic catheter (0 = 40). An hour after the endoscopic examination the subjects were asked to complete a questionnaire that addressed adverse symptoms induced by Lugol's iodine staining. Results: Sodium thiosulfate solution spray substantially reduced adverse symptoms that lasted more than 30 minutes after chromoendoscopy, compared with the no-treatment group. There was no significant difference in the proportion of subjects with symptoms between the Maalox and no-treatment groups. Cost of sodium thiosulfate solution spray per use was $0.15 (15 yen). Conclusions: Sodium thiosulfate solution is recommended for routine use after Lugol's staining.