On October 31, 2019 Castle Biosciences, Inc. (Nasdaq: CSTL), a skin cancer diagnostics company providing personalized genomic information to improve cancer treatment decisions, reported the presentation of results from a study validating a newly developed nomogram tool that combines information from the DecisionDx-Melanoma test with clinicopathologic features to improve prediction of patients’ risk of melanoma recurrence (Press release, Castle Biosciences, OCT 31, 2019, View Source [SID1234550140]).
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The study titled, "Development and validation of a clinically useful nomogram incorporating molecular clinicopathologic factors to predict risk of recurrence in patients with cutaneous melanoma," was presented during an Oral Abstract session at the American Society for Dermatologic Surgery (ASDS) Annual Meeting, October 24-27 in Chicago.
"The nomogram combines results from the DecisionDx-Melanoma prognostic test with clinical and pathological features to create an accurate tool that is designed to improve risk assessment beyond staging factors alone," said study co-author Ryan Thorpe, M.D., Ada West Dermatology, Meridan, Idaho. "Using the nomogram to estimate patient risk, we believe physicians can optimize treatment decisions such as sentinel lymph node biopsy, frequency of follow-up, the need for imaging, as well as evaluate entry into clinical trials."
Current melanoma guidelines recommend that treatment management be guided by an individual patient’s risk of metastasis or recurrence, which is impacted by clinical and pathologic features. This study combined the DecisionDx-Melanoma test result with clinicopathologic features to develop a nomogram tool that provides a more accurate determination of the risk of recurrence in patients with melanoma compared to clinical and pathologic features alone.
The study included a prospective cohort of 1,124 patients with melanoma from nine dermatology centers participating in the Cutaneous Oncology Research Consortium (CORC). Those with at least one year of follow-up or a recurrence event who also had complete clinicopathologic information and a DecisionDx-Melanoma result available were included in the nomogram development (n=685). The median follow-up time of this cohort was 3.0 years and median age was 67 years. The majority of patients had thin melanoma (84% had a tumor 1 mm deep or less), and ulceration was present in 7% of patients. The DecisionDx-Melanoma prognostic test for cutaneous melanoma predicts 5-year risk of recurrence and metastasis as low risk (Class 1, 1A lowest risk) or high risk (Class 2, 2B highest risk).
Key Study Findings:
Patients with Class 1A DecisionDx-Melanoma test results had significantly better recurrence-free survival (RFS) at 1.5 years compared to patients with Class 2B results (98.9% and 70.3%, respectively). Similar results were seen for distant metastasis-free survival (DMFS), with 99.6% survival for patients with a Class 1A result and 84.4% for those with a Class 2B result.
In a multivariate Cox regression model including DecisionDx-Melanoma and clinical features, only Breslow thickness and DecisionDx-Melanoma results were significant predictors for RFS (hazard ratio [HR] 1.25, p=0.0002 and 9.02, p<0.0001, respectively).
Researchers developed an optimized nomogram that includes American Joint Committee on Cancer (AJCC) T category (determined by tumor thickness and ulceration) and DecisionDx-Melanoma test results as the strongest variables contributing prognostic information. The nomogram was then independently validated for prediction of recurrence in a retrospective cohort of 901 patients who had a median follow-up of 5.8 years.
Using clinical and molecular variables, the validated nomogram improved recurrence risk prediction beyond clinicopathologic factors alone.
About DecisionDx-Melanoma
DecisionDx-Melanoma is a gene expression profile test that uses an individual patient’s tumor biology to predict individual risk of cutaneous melanoma metastasis or recurrence, as well as sentinel lymph node positivity, independent of traditional staging factors, and has been studied in more than 3,900 patient samples. Using tissue from the primary melanoma, the test measures the expression of 31 genes. The test has been validated in four archival risk of recurrence studies of 901 patients and five prospective risk of recurrence studies including more than 780 patients. Prediction of the likelihood of sentinel lymph node positivity has also been validated in two prospective multicenter studies that included more than 2,000 patients. Impact on patient management plans for one of every two patients tested has been demonstrated in four multicenter and single-center studies including more than 560 patients. The consistent performance and accuracy demonstrated in these studies provides confidence in disease management plans that incorporate DecisionDx-Melanoma test results.