Lower Lugol's Solution Concentration on Reducing the Adverse Symptoms of Chromoendoscopy With Iodine Staining

It is widely accepted that chromoendoscopy using Lugol's solution is effective for the detection of early esophageal squamous neoplasia. However, this modality may cause severe chest pain and discomfort owing to mucosal irritation. The conventional concentration of Lugol's solution is in the range of 1.2% to 2.5% . Image quality can be guaranteed with this range of Lugol's solution. However, lead to retrosternal pain and discomfort, and can even induce erosion or ulceration in the esophagus and stomach. This study was to test whether a lower concentration of Lugol's solution, which has minimal mucosal irritation, can provide satisfied image quality by a randomized blinded controlled trial.

• 1.2% Lugol's solution (Drug): This group patients were given concentrations of 1.2% Lugol's solution for chromoendoscopy.Then biopsy specimens will be taken at the well-demarcated unstained or less-stained lesions.
• 1.0% Lugol's solution (Drug): This group patients were given concentrations of 1.0% Lugol's solution for chromoendoscopy.Then biopsy specimens will be taken at the well-demarcated unstained or less-stained lesions.
• 0.8% Lugol's solution (Drug): This group patients were given concentrations of 0.8% Lugol's solution for chromoendoscopy.Then biopsy specimens will be taken at the well-demarcated unstained or less-stained lesions.
• 0.6% Lugol's solution (Drug): This group patients were given concentrations of 0.6% Lugol's solution for chromoendoscopy.Then biopsy specimens will be taken at the well-demarcated unstained or less-stained lesions.
• 0.4% Lugol's solution (Drug): This group patients were given concentrations of 0.4% Lugol's solution for chromoendoscopy.Then biopsy specimens will be taken at the well-demarcated unstained or less-stained lesions.

Primary outcomes

• Image Quality [intraoperative]: Image quality is blindly quantified by a 4-point scale from the endoscopists. A higher score representing higher image quality.

Secondary outcomes

• Gastric Mucosa Injury [1 months]: The gastric mucosal injury caused by Lugol's solution is defined as post-staining gastritis score minus pre-staining gastritis score in pCLE. The confocal gastritis was graded 0 to 3,according to pit patterns, capillaries, and fluorescein leakage. A higher score representing more serious injury.
• Adverse Events [24 hours]: Both a written and oral form of the Numerical Rating Scale (NRS) was provided to the patients after the endoscopy examination, used for measuring patients' retrosternal pain, retrosternal discomfort, nausea, abdominal discomfort and others. In NRS, 0 is painless, 10 is the most severe pain, less than 4 is mild pain (pain does not affect sleep), 4-6 is moderate pain, and more than 7 is severe pain (pain means unable to sleep or wake up from sleep).
• Severe Adverse Events [24 hours]: Severe adverse events includes allergic reactions, esophageal burns, spasms and even perforation.
• Tolerance [intraoperative]: The 4-point scale was used to assess the tolerance of endoscopist to the esophageal spasm caused by Lugol's solution which prevent endoscopy from passing. 1-4 means the resistance as intolerable, tolerable, mild, or non-existing.
• Histology analysis [3-5days]: All specimens were evaluated by two experienced pathologists blind to the groups of the patients. The macroscopic and histologic diagnosis were made based on Paris classification and Vienna classification, respectively.

Sex: All, ages: 40 Years to 74 Years, accepts healthy volunteers

Inclusion Criteria:

* patients in the high-risk population of ESCC;
* or general risk population of ESCC between 40 to 74 years old. Definition of high-risk population of ESCC is list in supporting information33.

Exclusion criteria included the following:

* with obvious abnormalities in stomach, confirmed by either white-light endoscopy (WLE) or pCLE, including gastric cancer, acute erosive and hemorrhagic gastritis, chronic atrophic gastritis, H. pylori infection and severe bile reflux gastritis;
* advanced esophageal carcinoma;
* known esophageal surgery or endoscopic treatment;
* known esophageal radiotherapy or chemotherapy;
* esophageal stenosis;
* food retention;
* allergy to iodine or fluorescein sodium;
* hyperthyroid;
* coagulopathy;
* acute bleeding;
* severe organ failure;
* pregnant or breastfeeding women.

• Results publication: Qu JY, Li Y, Liu GQ, Li Z, Zhong N, Zhang MM, Li YY, Yu T, Lu XF, Li LX, Liu H, Qi QQ, Li YQ, Zuo XL. Optimal concentration of Lugol's solution for detecting early esophageal carcinoma: A randomized controlled trial. J Gastroenterol Hepatol. 2023 Jun;38(6):962-969. doi: 10.1111/jgh.16190. Epub 2023 Apr 24. PMID 37094943

• Xiuli Zuo, PhD, Principal investigator, Qilu Hospital of Shandong University