
Castle Biosciences to Present New Data on DecisionDx-SCC at ASTRO 2023 Annual Meeting
Castle Biosciences, Inc. (Nasdaq: CSTL), has unveiled new data demonstrating the ability of its DecisionDx®-SCC test to predict which patients with node-negative cutaneous squamous cell carcinoma (SCC) are at a higher risk of metastasis, and could benefit from adjuvant radiation therapy (ART). This new data will be presented during the American Society for Radiation Oncology (ASTRO) 2023 Annual Meeting, scheduled for October 1-4 in San Diego.
Cutaneous squamous cell carcinoma (cSCC) poses a challenge in risk assessment due to its wide array of clinicopathologic risk factors. Dr. Jason Newman, study author and director of the Head & Neck Cancer Division at the Medical University of South Carolina, emphasized the difficulties in making treatment decisions when the risk of metastasis is uncertain. DecisionDx-SCC offers a complement to traditional risk stratification with objective information about a patient’s biological risk of metastasis.
The study evaluated whether DecisionDx-SCC (40-GEP) test results can enhance the selection of node-negative SCC patients at higher risk of metastasis, potentially benefiting from ART. The intermediate-risk group, where ART is often considered, was defined as Brigham and Women’s Hospital (BWH) stage T2a or higher. DecisionDx-SCC effectively stratified this cohort based on metastasis risk, demonstrating substantial differences in metastasis-free survival (MFS) rates. Patients with Class 1 results (low biological risk of metastasis) had a 92.4% MFS rate, compared to 76.1% for Class 2A (moderate risk) and 59.4% for Class 2B (high risk), underlining the test’s prognostic power to aid clinical decision making.
The study identifies a significant portion (46%) of the ART-eligible cohort that received a Class 1 test result, indicating a low risk of metastasis, suggesting that their treatment may be less intensive. Conversely, patients with traditionally low-risk BWH T1 stage who received Class 2A or 2B test results had a substantial risk of metastasis, making them potential candidates for adjuvant therapy.
These study findings are set to be published in the International Journal of Radiation Oncology.