Pre-procedure oral administration of pronase improves efficacy of lugol chromoendoscopy in esophageal squamous cell carcinoma screening: a prospective, double-blinded, randomized, controlled trial

Background and Aims Chromoendoscopy with Lugol’s staining is used to screen for early esophageal squamous cell carcinoma (ESCC). Its efficacy is greatly limited by unstandardized defoaming preparation. This study aimed to confirm whether pre-procedure oral administration of pronase could improve the diagnostic performance of Lugol chromoendoscopy in high-risk patients being screened for early ESCC. Methods A total of 955 patients at-risk were prospectively recruited for screening for ESCC. Patients were randomly assigned (1:1) to groups with or without (control group) pronase administration. Endoscopic diagnosis of early ESCC was based on the presence of pink-color sign in Lugol’s unstained area, and a biopsy was routinely conducted if the Lugol’s unstained lesion was larger than 0.5 cm. The early cancer detection rate was used as the primary endpoint. Results Pre-procedure oral administration of pronase improved mucosal visibility during Lugol chromoendoscopy ( P = 0.008). There were no differences in the number of Lugol’s unstained lesions between the 2 groups (23.27% [111/477] vs. 25.11% [120/478], P = 0.508). Meaningfully, the detection rate of ESCC (confirmed by histopathology) was significantly higher in the pronase group than in the control group (27.03% [30/111] vs. 17.50% [21/120], P = 0.041), as well as the detection rate of lesions with pink-color sign during chromoendoscopy (35.14% [39/111] vs. 13.33% [16/120], P < 0.001). The diagnostic performance of Lugol chromoendoscopy had improved with the use of pronase (area under the curve = 0.85 vs. 0.69, P = 0.019), accompanied by an increased sensitivity (86.67% vs. 47.62%, P = 0.004). There was no difference in the adverse events between the 2 groups ( P = 0.793). Conclusions Pre-procedure oral administration of pronase significantly increased the detection rate of early ESCC and optimized the diagnostic performance of Lugol chromoendoscopy, which should be recommended during routine endoscopic screening for early ESCC in high-risk patients. Trial registration Pronase improves efficacy of Lugol chromoendoscopy screening on esophageal cancerous lesions (NCT02030769).