Background and Aims

Lugol chromoendoscopy facilitates endoscopic visualization of esophageal dysplasia and carcinoma. Vitamin C solution (VCS) can theoretically neutralize free iodine, which causes mucosal irritation. The aim was to assess the safety and efficacy of VCS for relieving adverse symptoms caused by Lugol iodine staining.

Methods

Two hundred forty eligible patients were randomized to receive 20 mL of normal saline solution (NS), 5% sodium thiosulfate solution (STS), or 2% VCS after spraying 10 mL of 2% Lugol iodine solution on the mid-distal esophagus. The primary endpoints were statistically significant reductions in acute and late adverse symptom severity scores. The secondary endpoint was the discoloration effect on esophageal brown iodine-stained mucosa.

Results

Spraying both VCS and STS similarly decreased the severity scores of acute (NS vs VCS = 2.58 vs 1.61, P = .040; VCS vs STS = 1.61 vs 1.89, P > .999) and late (NS vs VCS = 1.70 vs 0.91, P = .002; VCS vs STS = 0.91 vs 1.38; P = .212) adverse symptoms after Lugol chromoendoscopy compared with spraying NS. Compared with STS spray, VCS spray alleviated acute acid regurgitation or heartburn (33% vs 15%, P = .017) and late retrosternal discomfort or pain (21% vs 9%, P = .027). Moreover, compared with spraying NS, spraying VCS quickly discolored the iodine-stained mucosa, with a better decolorization score (2.26 vs 3.56, P = .000), and the effects of fading iodine dye were similar between VCS and STS (3.56 vs 3.59, P = .908).

Conclusions

VCS can reduce mucosal irritation symptoms induced by Lugol chromoendoscopy and can be routinely recommended. (Chinese Clinical Trial Registry number: ChiCTR1900022000.)