Novel difficulty scoring system for endoscopic submucosal dissection in early gastric cardia cancer: multicenter Development and validation.

[BACKGROUND/AIM] Endoscopic submucosal dissection (ESD) for early gastric cardiac cancer (EGCC) faces anatomical challenges. This study aims to develop and validate a predictive model for ESD difficulty in EGCC, providing a basis for matching difficulty levels with endoscopists' experience.

[METHODS] This multicenter retrospective study included 514 EGCC patients from five tertiary hospitals (2017-2025). Patients from the 900th Hospital were randomized to training ( = 206) and internal validation ( = 164) cohorts; four other hospitals formed an external cohort ( = 144). Predictors with high collinearity (VIF ≥ 5) were excluded. Predictor selection was performed using LASSO regression, followed by multivariable logistic regression. Model performance was assessed using ROC curves, calibration plots, and decision curve analysis (DCA).

[RESULTS] The clinical scoring model incorporated four factors: Paris type III lesion (3 points), maximum diameter ≥3 cm (1 point), submucosal invasion (5 points), and lesion located on the anterior wall of the cardia (3 points). Model performance demonstrated an AUC of 0.784 (95% CI, 0.695-0.876) in the training cohort, 0.762 (95% CI, 0.653-0.884) in internal validation, and 0.740 (95% CI, 0.636-0.845) in external validation. Difficulty stratification was defined as: easy (0, 1, or 3 points), intermediate (4, 5, or 6 points), and difficult (8 or 11 points).

[CONCLUSION] This validated system optimizes endoscopist matching, reducing costs and recurrence in EGCC ESD.