FRIENDSWOOD, Texas--(BUSINESS WIRE)-- Castle Biosciences, Inc. (Nasdaq: CSTL), a dermatologic diagnostics company providing personalized genomic information to inform treatment decisions, today announced recent presentations on two of its skin cancer gene expression profile tests at the 2021 American Academy of Dermatology (AAD) Summer Meeting, held Aug. 5-8, 2021.
DecisionDx®-Melanoma:
DecisionDx-Melanoma is Castle’s gene expression profile test that uses an individual patient’s tumor biology to predict the risk of cutaneous melanoma metastasis or recurrence, as well as sentinel lymph node (SLN) positivity, independent of traditional staging factors.
“Integrating 31-gene expression profiling with clinicopathologic features improves prognostication of recurrence and metastasis in patients with stage I-III cutaneous melanoma” was presented by Nicholas Taylor, M.D., Ph.D., Zitelli and Brodland, P.C., Pittsburgh and Central Dermatology Center, Chapel Hill, N.C. in the Frontiers in Research, Science and Technology (FiRST) session on Saturday, Aug. 7.
“The study demonstrated that DecisionDx-Melanoma added significant prognostic value for a patient beyond traditional staging,” said Taylor. “The study further showed that the ability to integrate a patient’s unique tumor biology with their personal clinical and pathologic risk factors helped both patients and clinicians.”
Study methods and findings:
- DecisionDx-Melanoma’s 31-gene expression profile (31-GEP) has been validated to both identify patients at low risk of sentinel lymph node positivity and refine risk of recurrence prognosis.
- A new integrated algorithm (i31-GEP ROR (risk of recurrence) for outcomes prediction) was developed (n=1581) and validated (n=523) using Cox regression and 10x4-fold cross-validation on patients with stage I-III cutaneous melanoma from multiple centers.
- The final integrated outcomes prediction algorithm combined DecisionDx-Melanoma’s continuous 31-GEP score and patient-specific clinicopathologic risk factors, including Breslow thickness, ulceration, mitotic rate, age, tumor location, sentinel lymph node (SLN) status and/or the presence of microsatellites.
- Compared to American Joint Committee on Cancer Eighth Edition (AJCC8) staging, the i31-GEP ROR algorithm for outcomes prediction significantly improved the classification of overall risk for five-year recurrence-free survival (RFS), distant metastasis-free survival (DMFS) and melanoma-specific survival (MSS).
- Integrating DecisionDx-Melanoma’s continuous 31-GEP score with clinicopathologic features improves risk stratification over staging guidelines alone.
- Overall, the study demonstrated that DecisionDx-Melanoma’s i31-GEP ROR integrated test result was an independent, significant predictor of five-year RFS, DMFS and MSS, and that the i31-GEP ROR outcomes prediction algorithm provided an individualized risk estimate rather than an average, population-based risk estimate that can help personalize patient management decisions and overall risk assessments beyond standard melanoma staging.
DecisionDx®-SCC:
DecisionDx-SCC is Castle’s prognostic 40-gene expression profile (GEP) test for patients diagnosed with high-risk cutaneous squamous cell carcinoma (SCC), designed to use a patient’s tumor biology to predict individual risk of metastasis for patients with SCC and one or more risk factors.
“Risk assessment by the 40-gene expression profile (40-GEP) test further stratifies risk of metastasis in a subset of high-risk cutaneous squamous cell carcinoma (cSCC) patients meeting T1 staging criteria” was presented by Aaron Farberg, M.D., Baylor University Medical Center, Dallas in the Frontiers in Research, Science and Technology (FiRST) session on Saturday, Aug. 7.
“As a physician, it is important that I leverage all of the information available to me to make the best decisions for the care of each patient,” said Farberg. “This study demonstrated that by incorporating DecisionDx-SCC into their clinical practice, physicians can more confidently identify patients with a higher risk of metastasis, who may have otherwise been considered low-risk using traditional staging systems alone, which provides the ability to adjust their treatment plans for improved patient outcomes.”
Study methods and findings:
- Previous validation of the DecisionDx-SCC test in a high-risk SCC cohort (n=420, all high-risk or very- high risk by the National Comprehensive Cancer Network (NCCN) guidelines v1.2021 or meeting Appropriate Use Criteria for Mohs Micrographic Surgery) demonstrated independent prognostic value when the result was incorporated into existing risk assessment methods.
- Using this validation cohort, the objective of this study was to determine whether DecisionDx-SCC could identify biologically risky tumors within a subset of NCCN high-risk tumors comprehensively staged as T1 by either American Joint Committee on Cancer Eighth Edition (AJCC8) or Brigham and Women’s Hospital (BWH) staging (AJCC8 cohort n=222; BWH cohort n=200).
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Kaplan-Meier analysis demonstrated a statistically significant difference in three-year metastasis-free survival rates between DecisionDx-SCC risk groups:
- AJCC8 T1 cases – Class 1: 95.2%, Class 2A: 81.4%, Class 2B: 50%; p