Castle Biosciences Presents Data at ASCO 2018 Supporting Accuracy and Performance of the DecisionDx-Melanoma Test in Predicting Risk of Melanoma Recurrence

CHICAGO--()--Castle Biosciences, Inc., the skin cancer diagnostics company providing molecular diagnostics to improve cancer treatment decisions, today announced the presentation of data highlighting the accuracy and performance of the DecisionDx®-Melanoma gene expression profile (GEP) test at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting being held in Chicago, IL from June 1-5.

The study titled, “Performance of a 31-gene expression profile melanoma test in clinically relevant clinicopathologic subgroups” (Abstract #9583), will be presented as a poster at the meeting. Results from the 690-patient study show that the DecisionDx-Melanoma test improved clinical risk prediction independent of traditional factors and consistent with findings from previous retrospective and prospective studies.

Key Study Findings:

  • Results from this multicenter study in 690 patients confirm that the DecisionDx-Melanoma test is an independent predictor of risk for recurrence, metastasis and melanoma-specific death, including clinically relevant subgroups.
  • The subgroup of American Joint Committee on Cancer (AJCC) Stage I-IIA patients who had a Class 2B result (highest risk) had significantly worse recurrence-free survival (RFS), distant metastasis-free survival (DMFS) and melanoma-specific survival (MSS) rates compared to patients with a Class 1A result (lowest risk), important considerations that could impact surveillance and follow-up decisions.
  • For Stage IIIA patients, the DecisionDx-Melanoma test identified groups of patients with significantly different outcomes, which is increasingly important to inform decisions on adjuvant therapy and surveillance plans.

“Results from this multicenter study demonstrate that the GEP test can complement traditional AJCC staging factors by providing independent information that improves risk prediction for patients with melanoma,” commented Brian Gastman, M.D., Cleveland Clinic Lerner Research Institute, Cleveland, Ohio. “With new options for patients increasing at a rapid pace, many clinical decisions are being made based on extrapolating data from different studies. Having additional, objective information is important to help patients and their treating physicians make definitive decisions, especially when there isn’t a clearly defined management plan.”

Study Details:

Data from three previous DecisionDx-Melanoma validation studies were combined to enable analysis of clinically relevant subgroups. In this cumulative population of 690 Stage I-III patients, median age was 59 years, median time of follow-up was 6.5 years and median Breslow thickness was 1.3 mm. Seventy percent of patients had Stage I or II melanoma. The DecisionDx-Melanoma test was performed to determine molecular class for each patient, with a Class 1A result indicating the lowest 5-year risk of metastasis and a Class 2B result indicating the highest risk. Study endpoints included RFS (time to regional or distant metastatic event), DMFS (time to any metastatic event beyond the regional nodal basis) and MSS (time from diagnosis to death from melanoma).

Results confirm the prognostic accuracy of the DecisionDx-Melanoma test showing a significant difference among 5-year RFS rates for all groups. Patients with a Class 1A (lowest risk) result had an average RFS of 90% compared to 37% for Class 2B (highest risk) patients (p<0.0001). DMFS 5-year rates were 94% for Class 1A and 50% for Class 2B (p<0.0001). MSS 5-year rates were 99% for Class 1A and 75% for Class 2B (p<0.0001).

Based on Cox multivariate analysis in the Stage I-IIA subgroup, DecisionDx-Melanoma test class was found to be the only significant predictor of all three endpoints (RFS, DMFS and MSS; p<0.05 for all).

Additional Castle Biosciences Data at ASCO 2018

Preliminary data from the cutaneous squamous cell carcinoma (cSCC) development program will also be presented as a poster at the ASCO 2018 meeting (Abstract #9577). The study reports that preliminary gene expression based predictive models may offer important information about patient risk that builds on current staging methods. Results support the feasibility of the program to develop a clinically valuable test to predict which cSCC patients are at higher risk for local recurrence or regional/distant metastasis.

Additionally, an abstract highlighting the use of the DecisionDx-Melanoma test to identify a population of melanoma patients to assess risk of sentinel lymph node biopsy positivity (Abstract #e21611) will be included in the online ASCO 2018 proceedings.

About DecisionDx-Melanoma

The DecisionDx-Melanoma test uses tumor biology to predict individual risk of melanoma recurrence and sentinel lymph node positivity independent of traditional factors. Using tissue from the primary melanoma, the test measures the expression of 31 genes. The test has been validated in three multi-center studies that have included 690 patients and have demonstrated consistent results. Performance has also been confirmed in four prospective studies including 702 patients. The consistent high performance and accuracy demonstrated in these studies, which combined have included over 1,300 patients, provides confidence in disease management plans that incorporate DecisionDx-Melanoma test results. Prediction of the likelihood of sentinel lymph node positivity has also been validated in two prospective multicenter studies that included over 1,400 patients. Clinical impact has been demonstrated in multi-center and single-center studies showing that test results impact clinical management decisions for one of every two patients tested. More information about the test and disease can be found at

About Castle Biosciences

Castle Biosciences is a molecular diagnostics company dedicated to helping patients and their physicians make the best possible decisions about their treatment and follow up care based on the individual molecular signature of their tumor. The Company currently offers tests for patients with cutaneous melanoma (DecisionDx®-Melanoma, DecisionDx®-CMSeq; and uveal melanoma (DecisionDx®-UM, DecisionDx®-PRAME and DecisionDx®-UMSeq;, with development programs in other underserved cancers. Castle Biosciences is based in Friendswood, TX (Houston), and has laboratory operations in Phoenix, AZ. More information can be found at

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are the trademarks of Castle Biosciences, Inc. Any other trademarks are the property of their respective owners.


Castle Biosciences
Derek Maetzold, 866-788-9007
President and CEO

Social Media Profiles


Castle Biosciences
Derek Maetzold, 866-788-9007
President and CEO