Shall we score? The SHALL-WE score for optimizing sclerotherapy in superficial lymphatic malformations

PURPOSE: No standardized tool guides the decision of when to escalate beyond sclerotherapy in lymphatic malformations (LMs). We developed the SHALL-WE score (Severity, Histology, And Location-Lymphatic malformation: When to Escalate) to define the optimal sclerotherapy threshold in superficial LMs. METHODS: We analyzed 709 patients with superficial LMs from a nationwide survey in Japan. Multivariable logistic regression identified predictors of treatment success, used to construct the SHALL-WE score (0-3 points): head and neck location, non-cystic histology, and severe disease (1 point each). The optimal threshold was the session count beyond which success rates fell below the overall mean (63.0%). RESULTS: Treatment success rates decreased with increasing score (score 0: 71.6%, 1: 64.1%, 2: 43.6%, 3: 20.0%; p < 0.001). Optimal thresholds were two sessions for score 0, one for score 1, and early escalation for scores 2-3. Patients managed within thresholds had higher success rates (71.9% vs. 51.2%; adjusted OR 1.921, 95% CI 1.340-2.753, p < 0.001). CONCLUSION: The SHALL-WE score defines when sclerotherapy is unlikely to succeed and treatment escalation should be considered. Prospective external validation is warranted.