On May 19, 2020 Castle Biosciences, Inc. (Nasdaq: CSTL), a skin cancer diagnostics company providing personalized genomic information to improve cancer treatment decisions, reported the publication of an intended use survey for DecisionDx-SCC, its prognostic test for patients diagnosed with high-risk cutaneous squamous cell carcinoma (SCC) (Press release, Castle Biosciences, MAY 19, 2020, View Source [SID1234558287]). The test is expected to be launched commercially in the third quarter of 2020.

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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

When comparing DecisionDx-SCC risk classes with clinicopathologic risk factors, Class 2B DecisionDx-SCC result, perineural invasion, immunosuppression, invasion beyond subcutaneous fat, and tumor diameter >1cm on the scalp were identified as the features most highly associated with risk of metastasis.
Adding a DecisionDx-SCC low-risk Class 1 result to clinicopathologic information led to an overall reduction in treatment plan modality intensity by more than 60% when compared to clinicopathological features alone.
Adding a Decision-SCC Class 2B test result to clinicopathologic information led to an overall escalation in treatment plan modality intensity by more than 90% when compared to clinicopathological features alone.
More than 95% of the management recommendations were in a risk appropriate direction compared to the DecisionDx-SCC class result, and all changes were within established NCCN-guidelines for patient management.
DecisionDx-SCC is the second skin cancer test discovered, developed and validated by Castle Biosciences.

About Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (SCC) is one of the most common cancers. Approximately 1 million patients are diagnosed with SCC each year in the U.S. While the majority of patients have a favorable prognosis, approximately 200,000 patients are identified as high risk. National guidelines provide for broad, aggressive treatment plan recommendations relative to low-risk patients. Traditional clinicopathologic based risk-factor staging systems suffer from low positive predictive value; meaning many more patients are classified as high risk than actually develop metastatic disease. This may lead to over- and under-treatment of a substantial number of cutaneous SCC patients. To address this clinical need, Castle Biosciences has developed a gene expression profile test designed to improve upon current staging systems and identify patients with cutaneous SCC at high risk for metastasis, in order to enable more informed, objective clinical decisions regarding adjuvant therapy and other management options.