Castle Biosciences‘ DecisionDx-Melanoma gene expression profile (GEP) test is a promising tool to identify melanoma patients at high risk of developing metastatic disease, according to recently presented data from five studies — one from Castle and four independent studies.
The research was presented at the 70th Society of Surgical Oncology Annual Cancer Symposium (SSO) March 15-18 in Seattle, Washington.
“We know that there is a decline in the rate of sentinel lymph node positivity with increasing age, which in turn reflects a greater need for accurate prognostic tools like DecisionDx-Melanoma,” lead study author Jonathan S. Zager, MD, FACS, said in a press release.
“These study results confirm that the GEP test is a useful tool for accurately determining metastatic and mortality risk estimates in melanoma patients — including the older patients for whom the decision to perform a sentinel lymph node biopsy may be impacted by increased comorbidities, surgical risk, and shorter life expectancy,” added Zager, who is also a professor of surgery in the Cutaneous Oncology and Sarcoma departments at the Moffitt Cancer Center in Tampa, Florida.
In the poster titled “Melanoma Risk Prediction in Elderly Melanoma Patients with a 31-Gene Expression Profile Test,” Castle researchers reported the results of 163 patients ages 70 and older who were evaluated with the DecisionDx-Melanoma GEP test to determine the risk of metastases. A Class 1 result indicated low risk, while a Class 2 result indicated high risk.
The results of the GEP analyses were assessed along with sentinel lymph node biopsy (SLNB), a more traditional method of predicting the various stages of the disease.
A total of 113 patients were tested with both GEP and SLNB. The researchers then evaluated distant metastasis-free survival (DMFS) and melanoma-specific survival (MSS), the two co-primary endpoints of the study.
Results showed that the DecisionDx-Melanoma test was a significant predictor of DMFS at five years, with a prognostic accuracy of 92% for low-risk disease (Class 1), and 53% for high-risk disease (Class 2).
The five-year melanoma-specific survival (MSS) rates were 98% for patents at low risk of metastasis and 75% for patients at high risk of metastasis. The researchers concluded that the DecisionDx-Melanoma test provides a good prognostic value of a patient’s individual risk of metastasis and adds prognostic value to traditional staging methods.
When the team combined the DecisionDx-Melanoma test results with those from the sentinel lymph node (SLN) biopsies, they found that the five-year DMFS rate was 91% for patients who were both SLN negative and at low risk of metastasis, vs. 78% for SLN alone. Similarly, SLN positive patients with a high risk of metastasis had a five-year DMFS of 40% vs. 51% for SNL alone.
“These data add to the robust support from multiple independent studies showing that DecisionDx-Melanoma is a clinically important tool that can accurately identify a patient’s individual risk of metastasis,” said Federico A. Monzon, MD, FCAP, chief medical officer of Castle Biosciences.
“Use of the DecisionDx-Melanoma test can complement traditional staging tools to better identify patients at high risk for distant metastasis, enabling implementation of management plans that are consistent with their individual risk.”
Another study presented at the conference, titled “Impact of Genetic Expression Profile on Decision-Making in Clinically Node Negative Melanoma Patients after Surgical Staging,” was presented by a research team from Oregon Health and Science University. This study assessed the management of patients who received the DecisionDx-Melanoma test after they had been diagnosed with cutaneous melanoma.
While the majority of deaths due to melanoma are seen in patients who were diagnosed with early-stage disease, current guidelines do not include routine exams for patients with stage 1 or 2a melanoma.
Based on data from previous studies showing a high prognostic value of using the DecisionDx-Melanoma test, the research team included the test in the risk assessment of 119 patients. Of these, 91 patients also had a sentinel lymph node biopsy performed.
The researchers found that 56% of patients with a low risk of metastasis (Class 1) were followed by a dermatologist, compared to none of the patients at high risk of metastasis (Class 2).
In addition, the team found that 66% of patients at high risk of metastasis were followed by surgical or medical oncology with a recommendation for an adjuvant trial, compared to 19% of patients at low risk of metastasis (Class 1).
The researchers also found that the DecisionDx-Melanoma results had a significant impact in the clinical management of patients with Stage 1 or Stage 2 melanoma.
A team of researchers at Fox Chase Cancer Center and Thomas Jefferson University Hospital in Philadelphia presented another study titled “Combined Experience of Two Tertiary Referral Centers with MelanomaDx GEP Testing.”
The team reported the outcomes of 95 patients with Stage 1, 2, or 3 cutaneous melanoma who received the DecisionDx-Melanoma test in combination with standard staging factors.
The study found that only 4.9% of patients at low risk of metastasis (Class 1) had disease recurrence, compared to 24.1% of patients at high risk (Class 2). Among the Class 2 patients who had a recurrence, 77% had a distant metastasis.
During the conference, two other studies reported the results of applying the GEP test. Xin Huang and colleagues presented the study “Application of Gene Expression Profiling in the Management of Cutaneous Melanoma,” while Jennifer K. Keller and colleagues presented the study “Utility of Gene Expression Profiling in Determining Necessity of Sentinel Node Biopsy in Melanoma.”
