Castle Biosciences announces new data from study evaluating i31SLNB

Castle Biosciences (CSTL) announced new data from the largest prospective multicenter study to date evaluating DecisionDx-Melanoma’s integrated sentinel lymph node biopsy, i31SLNB, test result. The study data, recently shared at the SSO 2026 Annual Meeting, confirm that the i31-SLNB accurately predicts SLN positivity and identifies low-risk patients who may safely consider forgoing SLNB while maintaining favorable long-term outcomes. These results expand upon earlier publications from the same prospective multicenter clinical study and further strengthen the growing body of evidence supporting the role of DecisionDx-Melanoma in guiding SLNB decision-making. Together, the study findings underscore two key conclusions from the prospective study: 1) DecisionDx-Melanoma identifies low-risk patients who have favorable outcomes, with very low nodal positivity rates and high three-year RFS. 2) DecisionDx-Melanoma also identifies patients at high risk of nodal positivity, providing clear and clinically meaningful separation between low- and high-risk groups.