Castle's DecisionDx-Melanoma Test Results Can Slash the Number of Sentinel Lymph Node Biopsies

Use of the tests’ results within current guideline recommendations led to a significant reduction in SLNB procedures performed.

Castle Biosciences, Inc.’s DecisionDx-Melanoma test results influenced 85% of clinicians’ decisions regarding the sentinel lymph node biopsy (SLNB) surgical procedure, a new study shows.

Additionally, use of the tests’ results within current guideline recommendations led to a significant reduction in SLNB procedures performed, demonstrating the potential clinical value of the test to guide risk-aligned patient care.

“DecisionDx-Melanoma is the best-studied molecular test for use in cutaneous melanoma to date, with studies involving more than 10,000 research subjects. DecisionDx-Melanoma provides personalized information about a patient’s risk of sentinel lymph node (SLN) positivity to inform decisions about whether to safely forego or pursue an SLNB,” says Maki Yamamoto, M.D., board-certified surgical oncologist and associate professor of surgery at the University of California-Irvine School of Medicine in Orange, California, in a news release. “The data from this prospective, multicenter study showed that clinicians who used the test performed fewer SLNBs overall, which can alleviate complication rates and high costs associated with the procedure and focus surgical procedures on patients who have a greater likelihood of being SLN positive.”

This prospective, multicenter study included patients with invasive cutaneous melanoma who were being considered for an SLNB procedure and had a T-stage of:

• • T1a (and at least one adverse, high-risk feature),
  • T1b or
  • T2.

Clinicians received DecisionDx-Melanoma test results prior to making final SLNB decisions and were asked which features influenced their decision on whether to perform the procedure. Potential influencing factors included DecisionDx-Melanoma test results, patient preference and clinical and pathological features.

The data showed that DecisionDx-Melanoma test results influenced 85% of SLNB decisions, the highest percentage reported in the study, followed by patient preference.

When DecisionDx-Melanoma test results influenced for SLNB, the procedure was performed in 92% of the cases in the study; similarly, when the test result influenced against SLNB, the decision was made to forego SLNB in 70% of cases. These data show that use of the test’s results can guide risk-aligned, clinical decision-making regarding the SLNB surgical procedure, within current guidelines. Of the remaining 30% of cases where the clinician's decision was influenced by DecisionDx-Melanoma test results to forego SLNB but the biopsy was performed, 83% were influenced by patient preference.

Patients receiving a high-risk (Class 2B) DecisionDx-Melanoma test result had a 22% SLN positivity rate, more than double the historical positivity rate in this patient population.

The use of DecisionDx-Melanoma test results within current guidelines resulted in a significant reduction in SLNB procedures performed, compared to SLNB decisions based on a patient’s clinicopathologic risk factors alone (p<0.01).

“We believe DecisionDx-Melanoma has the ability to influence management decisions based on ample evidence provided in more than 40 peer-reviewed studies and the experience of clinical use in more than 120,000 patients," adds Robert Cook, Ph.D., senior vice president of research and development at Castle Biosciences. "We also believe that the use of molecular tests to guide clinical decisions adds value that is independent from the clinicopathologic risk factors traditionally used in melanoma risk assessment. We are pleased the DECIDE study results showed that using our DecisionDx-Melanoma test in combination with clinicopathologic features demonstrated superiority over the use of clinicopathologic factors alone to guide appropriate decisions about SLNB use.”3

The study is published in Current Medical Research and Opinion.