Switching from endoscopic submucosal dissection to salvage piecemeal knife-assisted snare resection to remove a lesion: a preoperative risk score from the beginning

Background and aims: endoscopic submucosal dissection (ESD) in the Western setting remains a challenge. Therefore, other simplified techniques such as knife-assisted snare resection (KAR) have been reported to overcome this issue. Methods: patients who underwent an ESD for the treatment of gastrointestinal neoplasms were included in a retrospective cross-sectional observational study. Factors associated with the end of ESD as a salvage p-KAR were identified and a logistic regression model was developed. Results: a total of 136 lesions in 133 patients were analyzed. Operator experience of under 50 cases and the combination of lesion size > 30 mm and colorectal location were independent predictive factors for switching to a salvage p-KAR according to the multivariate logistic regression analysis. We developed a risk scoring system based on these four variables (experience, size, location and the combination of size and location) with a receiver operating characteristic curve of 0.81 (95% CI: 0.74-0.89). The diagnostic accuracy of the score for a cut-off point ≥ 5 had a sensitivity of 0.79 (95% CI: 0.66-0.93) and a specificity of 0.71 (95% CI: 0.61-0.80). Conclusion: a simple predictive score system that includes four preoperative factors accurately predicts ESD to finish as a p-KAR. A careful selection of cases considering these variables could be useful to achieve better outcomes in the Western setting.