Castle Biosciences, Inc. will share new data at the 20th European Association of Dermato-Oncology (EADO) Congress, being held April 4-6, 2024, in Paris, France, that demonstrate the ability of its DecisionDx-Melanoma and DecisionDx-SCC tests to improve clinical-decision making through precise risk-stratification of patients with cutaneous melanoma (CM) and squamous cell carcinoma (SCC). Castle will present the following posters at EADO: DecisionDx-Melanoma: Title: Patients who forego sentinel lymph node biopsy after 31-GEP testing are not harmed: A prospective, multicenter analysis. Summary: This study shares data from Castle?s prospective, multicenter study of patients with T1-T2 CM tumors who were being considered for an SLNB.

Within a median follow-up time of two years, none of the patients with low-risk DecisionDx-Melanoma test results (Class 1A) who decided to forego SNLB based on their results had a tumor recurrence. These study data support use of the DecisionDx-Melanoma test to inform SLNB decisions and show that it can identify patients at low risk of sentinel lymph node (SLN) positivity who may safely forego the SLNB procedure, reducing healthcare costs and procedure complications. Title: The health economic impact of the 31-gene expression profile test for treatment and surveillance management plans in patients with cutaneous melanoma.

Summary: The DecisionDx-Melanoma test has been validated to predict individual risk of SLNB positivity and five-year risk of recurrence and metastasis for patients with CM. This study explored the cost-savings impact of using the DecisionDx-Melanoma test to guide risk-aligned clinical decision-making versus using the current melanoma staging standard, a patient?s AJCC stage. Costs of National Comprehensive Cancer Network (NCCN) guideline-recommended practices for patients with melanoma that were evaluated in the study included: SLNB, clinical visit schedules, imaging surveillance and adjuvant treatment for eligible patients.

The study determined that using DecisionDx-Melanoma test results to guide decision-making could save commercial payers more than $3 million (30% cost savings per one million plan members over five years) compared to care guided by AJCC stage, with 95% of such potential cost savings occurring during the first year post-diagnosis (year one projected savings of approximately $2.5 million). DecisionDx-SCC: Title: Evaluating the performance of a clinicopathological prognostic nomogram and utility of the 40-gene expression profile (40-GEP) test in refining risk of metastasis in high-risk cutaneous squamous cell carcinoma (HR-cSCC) patients. Summary: The DecisionDx-SCC test uses a patient?s tumor biology to independently predict risk of regional or distant metastasis in patients with high-risk SCC.

The test has also been shown to improve the accuracy of risk predictions when used with other risk assessment approaches, including NCCN guidelines. This study evaluated the performance of a risk-stratification nomogram developed in Europe (Rentroia-Pacheco, et al, 2023) in a U.S. cohort of high-risk SCC patients (n=760) and the additional prognostic value provided by the DecisionDx-SCC test. In the study, the nomogram misclassified nine out of 10 tumors that metastasized as low risk.

When the same tumors were tested using DecisionDx-SCC, 42% of those that the nomogram classified as low risk of metastasis were classified as high risk by the test, as well as 70% of all tumors that metastasized. These data demonstrate that DecisionDx-SCC improves the accuracy of risk assessment based solely on clinicopathological risk factors, leading to more appropriate risk-aligned management plans for patients with high-risk SCC.