Core Insights - The study presented at the Society of Surgical Oncology (SSO) 2026 Annual Meeting highlights the effectiveness of the DecisionDx-Melanoma test in predicting sentinel lymph node (SLN) positivity and guiding clinical decisions regarding SLNB [1][3]. Group 1: Study Findings - The DecisionDx-Melanoma test demonstrated an actual SLN positivity rate of 2.6% for patients with a predicted risk of less than 5%, confirming its clinical utility [2][5]. - In the T1b–T2a tumor subgroup, only 1.4% of patients with a predicted risk of less than 5% had a positive node, while those with a high-risk result (greater than 10%) had an SLN positivity rate of 18.5% [6][7]. - Patients identified as low risk exhibited a 97.8% three-year recurrence-free survival (RFS) rate, indicating favorable long-term outcomes [7]. Group 2: Clinical Implications - The NCCN guidelines recommend forgoing SLNB when the likelihood of finding a positive SLN is less than 5%, which aligns with the findings of the DecisionDx-Melanoma test [4]. - The i31-SLNB algorithm integrates a 31-gene expression profile (GEP) score with clinicopathologic factors, providing a personalized risk assessment that enhances decision-making for SLNB [4][9]. - The study reinforces the ability of DecisionDx-Melanoma to differentiate between low- and high-risk patients, thereby supporting more informed clinical decisions [8][10]. Group 3: Company Overview - Castle Biosciences, Inc. is focused on developing innovative tests that improve patient care, particularly in dermatologic and gastroenterological diseases [11]. - The DecisionDx-Melanoma test has been validated in over 10,000 patient samples and has been ordered more than 220,000 times since its launch, demonstrating its widespread acceptance and clinical relevance [10].