Clinical impact of a 31-gene expression profile test for cutaneous melanoma in 156 prospectively and consecutively tested patients

Abstract

Objective: DecisionDx-Melanoma* is a 31-gene expression profile test that predicts the risk of metastasis in patients with primary cutaneous melanoma (CM). This study was designed to ascertain clinical management changes determined by the test outcome, which classifies CM patients being at low (Class 1) or high (Class 2) risk for recurrence.

Research design and methods: Medical charts were reviewed from 156 CM patients from six institutions (three dermatology and three surgical oncology practices) who were consecutively tested between May 2013 and December 2015. Clinical management data that were compiled and compared before and after receipt of the 31-gene expression test result included frequency of physical exams, frequency and modality of imaging, and referrals to surgical and medical oncologists.

Results: Forty-two percent of patients were Stage I, 47% were Stage II and 8% were Stage III. Overall, 95 patients (61%) were Class 1 and 61 (39%) were Class 2. Documented changes in management were observed in 82 (53%) patients, with the majority of Class 2 patients (77%) undergoing management changes compared to 37% of Class 1 patients (p < 0.0001 by Fisher’s exact test). The majority (77/82, 94%) of these changes were concordant with the risk indicated by the test result (p < 0.0001 by Fisher’s exact test), with increased management intensity for Class 2 patients and reduced management intensity for Class 1 patients.

Conclusions: Molecular risk classification by gene expression profiling has clinical impact and influences physicians to direct clinical management of CM patients. The vast majority of the changes implemented after the receipt of test results were reflective of the low or high recurrence risk associated with the patient’s molecular classification. Because follow-up data was not collected for this patient cohort, the study is limited for the assessment of the impact of gene expression profile based management changes on healthcare resource utilization and patient outcome.

Keywords:

• Clinical decision-making
• disease management
• gene expression profile
• melanoma

Transparency

Declaration of funding

This study was sponsored by Castle Biosciences Inc. The participating institutions received financial compensation to account for costs associated with the conduct of the study.

Declaration of financial/other relationships

C.E.J., D.J.M., B.M., K.M.O., R.W.C., and F.A.M. have disclosed that they are employees of Castle Biosciences Inc. and hold stock in the company. A.C.B., R.S.D., J.K.P, I.C., R.H., A.B., and A.M. received sponsorship and research funding from Castle Biosciences, Inc. A.C.B., I.C., and A.R.M. have served on the Speaker's Bureau for Castle Biosciences, Inc.

CMRO peer reviewers on this manuscript have received an honorarium from CMRO for their review work. Peer reviewer 1 has disclosed that he is a consultant to Dermtech Inc., Myriad Genetics, and Castle Biosciences. Peer reviewer 2 has no relevant financial or other relationships to disclose.

Acknowledgments

Castle Biosciences Inc. employee Kristen Meldi Plasseraud participated in the writing and data analysis of this study.