Post written by Duochen Jin, PhD, Jun Wang, MB, Qiang Zhan, MD, PhD, Keting Huang, MM, Hui Wang, MD, Guoqiang Zhang, MD, Yinghong Xu, MB, Jian Yao, MB, Rong Sun, MB, Qin Huang, MD, PhD, Feng Ye, PhD, and Guoxin Zhang, PhD, from the Department of Gastroenterology, First Affiliated Hospital of Nanjing Medical University, First Clinical Medical College of Nanjing Medical University, Endoscopic Center, First Affiliated Hospital of Nanjing Medical University, Nanjing, Department of Gastroenterology and Hepatology, Jinhu County People’s Hospital, Huaian, Department of Gastroenterology and Hepatology, Wuxi People’s Hospital Affiliated with Nanjing Medical University, Wuxi, China, Department of Pathology and Laboratory Medicine, Veterans Affairs Boston Healthcare System and Harvard Medical School, West Roxbury, Massachusetts, USA.

This study aimed at assessing the effectiveness of VCS spray compared with NS spray and STS spray for relieving the mucosal irritation associated with Lugol chromoendoscopy.

Chromoendoscopy with Lugol iodine solution increases the sensitivity for detecting early mucosal lesions and targeting biopsies from unstained areas. Lugol chromoendoscopy has been widely used to screen esophageal dysplasia because it requires only standard endoscopic equipment and is easy to perform.

However, iodine can irritate and erode the upper digestive tract mucosa, leading to adverse events, including retrosternal pain and discomfort. In most medical centers, endoscopists simply use normal saline solution (NS) to flush the iodine-dyed mucosa to alleviate subsequent discomfort, and some medical centers use sodium thiosulfate solution (STS) spray to neutralize iodine staining. NS flushing relieves the discomfort to a limited extent, and STS has not been widely used. Hence, there is an urgent need for a widely available and economical method that can significantly reduce adverse events after Lugol chromoendoscopy, thus improving the compliance of patients with chromoendoscopy and the detection rates of esophageal dysplasia and carcinoma.

This study is the first randomized, parallel, noninferiority trial of VCS spray for the effects of endoscopic mucosal decolorization and discomfort relief after Lugol iodine staining. We found that spraying 2% VCS or 5% STS on the esophageal mucosa had similar efficacy in decreasing the severity scores of acute and late symptoms after Lugol chromoendoscopy. Moreover, the effects of fading iodine dye were also similar between VCS and STS. Correlation analysis revealed that late adverse symptoms were apparently negatively correlated with decolorization effect scores.

Vitamin C significantly alleviates the adverse symptoms of patients after iodine staining; however, some people still worry that the product of this chemical reaction, hydrogen iodide (HI), has side effects on patients. Therefore, we are currently evaluating the safety of the low-dose HI produced by this new method and look forward to the opportunity to continue sharing our research results in GIE in the future.

Based on these preliminary results, our hospital uses 2% VCS to relieve adverse symptoms after iodine staining. Because vitamin C is inexpensive and accessible, even in community hospitals, we recommend the routine use of 2% VCS for Lugol chromoendoscopy.

Figure 4. Severity scores of all acute and late adverse symptoms for each patient in the 3 groups. NS, Normal saline solution; STS, sodium thiosulfate solution; VCS, vitamin C solution.

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