New Data at ASTRO 2024 Shows Castle Biosciences’ DecisionDx®-SCC Test Provides More Precise Risk Stratification Than BWH Staging Alone to Guide Intensified Treatment for Immune Suppressed Patients with High-Risk Cutaneous Squamous Cell Carcinoma

In the study, patients with lower-stage Brigham and Women's Hospital (BWH) T1-T2a cutaneous squamous cell carcinoma (SCC) tumors were further stratified into distinct groups of those with more or less favorable survival by the DecisionDx-SCC test, including in the T2a immunosuppressed patient subset which showed a higher rate of metastasis

FRIENDSWOOD, Texas--(BUSINESS WIRE)-- Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced new data demonstrating the ability of its DecisionDx-SCC test to provide clinically impactful risk stratification in high-risk SCC patient sub-populations (i.e., patients with suppressed immune systems in this study) to guide potential treatment intensification, such as adjuvant radiation therapy (ART). The data will be shared in an oral presentation at the American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting, being held Sept. 29-Oct. 2 in Washington, D.C.

“The DecisionDx-SCC test has been validated to independently predict likelihood of metastasis beyond staging and clinicopathologic risk factors to help inform important treatment decisions for patients with SCC,” said Shlomo A. Koyfman, M.D., lead study author and radiation oncologist at Cleveland Clinic.1-3 “The data we are sharing at ASTRO highlights the utility of the test in immune suppressed patients with lower-stage SCC tumors, who may have an elevated risk of metastasis due to their immune status and thus may benefit from intensified surveillance and adjuvant treatments, such as radiation, following tumor removal to reduce this risk.”4,5

Details regarding Castle’s oral presentation at ASTRO are included below:

• Abstract title: Use of the 40-gene expression profile (40-GEP) test to identify immune suppressed patients with Brigham and Women’s Hospital (BWH) T1-T2a cutaneous squamous cell carcinoma (cSCC) at higher risk of metastasis: Implications for adjuvant radiation
• Abstract ID: 1065
• Lead Authors: Shlomo A. Koyfman, M.D., and Karina Brito, Cleveland Clinic
• Session Type: Quick Pitch
• Session: QP 12 - Sarcoma 2: Advancing Treatment Frontiers in Cutaneous Malignancies and Sarcoma
• Date & Time: Tuesday, Oct. 1, 2:30-2:40 p.m. Eastern Time
• Location: Room 151
• Summary: Data from an independent validation cohort of 954 SCC patients with at least one National Comprehensive Cancer Network (NCCN) high-risk factor and DecisionDx-SCC test results were analyzed for patients with BWH T1 and T2a tumors with no residual tumor after Mohs surgery; 441 patients with BWH T1 tumors and 336 with BWH T2a tumors were included in the study cohort. Patients with T1 tumors had similar metastasis-free survival (MFS) rates regardless of immune status yet were further stratified by their DecisionDx-SCC test result (3-year MFS: Class 1 test result: 96.9% vs. Class 2A/2B test result: 88.6%, p