New Data Demonstrates Significant and Risk-Appropriate Clinical Impact of DecisionDx-SCC Test Results on Patient Management Decisions

Castle Biosciences, Inc. (Nasdaq: CSTL), a skin cancer diagnostics company providing personalized genomic information to improve cancer treatment decisions, today announced the publication of an intended use survey for DecisionDx-SCC, its prognostic test for patients diagnosed with high-risk cutaneous squamous cell carcinoma (SCC). The test is expected to be launched commercially in the third quarter of 2020.

The article titled, “Impact of a prognostic 40-gene expression profiling test on clinical management decisions for high-risk cutaneous squamous cell carcinoma,” was published in the peer-reviewed journal, Current Medical Research and Opinion (CMRO).

Results of the study demonstrate that integration of DecisionDx-SCC (40-gene expression profile test) results impacted management decisions in a significant and risk-appropriate manner for high-risk SCC patient scenarios, while remaining aligned with national guidelines for patient management.

“It is critical that management and follow-up recommendations for patients diagnosed with high-risk cutaneous squamous cell carcinoma are tailored to individual risk, yet current staging methods are often unable to precisely stratify different risk groups that may have markedly different outcomes,” said principal investigator Darrell Rigel, M.D., M.S., Clinical Professor at New York University School of Medicine. “These results demonstrate that information on tumor biology can impact clinical decisions in a significant, risk-appropriate manner.”

Disease and Study Background

• Approximately 1 million patients are diagnosed with SCC of the skin in the U.S. each year, and the incidence continues to grow; while the majority of patients have a favorable prognosis, approximately 200,000 patients are identified as high risk.
• National Comprehensive Cancer Network (NCCN) guidelines for SCC define treatment pathways based on risk of local recurrence or metastasis. For SCC, there are two clinicopathologically defined categories: low risk and high risk. NCCN defines high risk as SCC patients with one or more of several high-risk clinicopathologic features.
• DecisionDx-SCC stratifies patients into three categories based on risk of metastasis: Class 1 (low-risk), Class 2A (high-risk) and Class 2B (highest-risk).The study objective was to determine the impact of DecisionDx-SCC test results on clinician management decisions and how their choices would align with an NCCN compliant, risk-directed management plan for high-risk SCC.
• 162 clinicians attending a national dermatology conference were presented with DecisionDx-SCC test validation data. They were then asked to rate clinicopathological features and DecisionDx-SCC test results to assess their opinion of how concerning each is to SCC prognosis. When presented with vignettes describing patients with NCCN-defined high-risk features, clinicians were asked to document their treatment plan pre-test (without DecisionDx-SCC results), then, post-test (with DecisionDx-SCC Class 1, 2A, or 2B results) methodology along with corresponding metastasis rates for each test group. Assessed treatment plan modalities included follow-up schedule, sentinel lymph node biopsy, nodal imaging, adjuvant radiation and adjuvant chemotherapy.

Study Findings