Castle Biosciences Presents New Data at ASTRO 2023 Highlighting Risk-Stratification Performance of DecisionDx®-SCC in Patients with Cutaneous Squamous Cell Carcinoma Eligible for Adjuvant Radiation Therapy

FRIENDSWOOD, Texas--(BUSINESS WIRE)-- Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, will share new data demonstrating the ability of its DecisionDx®-SCC test to identify node-negative cutaneous squamous cell carcinoma (SCC) patients at a higher risk of metastasis who may benefit from adjuvant radiation therapy (ART). The data will be shared in an oral presentation during the American Society for Radiation Oncology (ASTRO) 2023 Annual Meeting, being held Oct. 1-4 in San Diego.

“Risk stratification for patients with SCC can be challenging due to broad staging guidelines based on a wide range of clinicopathologic risk factors,” said Jason Newman, M.D., study author and director of the Head & Neck Cancer Division at Medical University of South Carolina. “When a patient’s risk of metastasis is unclear, tough decisions as to which treatment approaches to pursue become that much more difficult. DecisionDx-SCC complements traditional risk stratification with independent and objective information on a patient’s biologic risk of metastasis that can be invaluable in guiding risk-aligned treatment decisions, such as consideration of radiation therapy for a patient.”

Details regarding Castle’s presentation are as follows:

Abstract ID 1180: Risk-stratification using the 40-gene expression profile (40-GEP) test identifies patients with node negative cutaneous squamous cell carcinoma (cSCC) at higher risk of metastasis who may benefit from adjuvant radiation therapy (ART) Session #: QP 16 Session: H&N 3: Innovative Approaches to Individualizing Therapy for Head & Neck and Skin Cancer Date & Time: Tuesday, Oct. 3 from 5:15-6:15 p.m. Pacific Time

The study aimed to evaluate whether DecisionDx-SCC (40-GEP) test results could refine the ability to select node negative SCC patients at a higher risk of metastasis who are most likely to benefit from ART. An intermediate risk population in which ART is often considered was defined as Brigham and Women’s Hospital (BWH) stage T2a or higher (n=489). DecisionDx-SCC significantly stratified the cohort according to risk of metastasis, with metastasis-free survival (MFS) rates of 92.4%, 76.1% and 59.4% for patients with Class 1 (low biological risk of metastasis), Class 2A (moderate risk) and Class 2B (high risk) test results, respectively (p