Impact of a 31-gene Expression Profiling Test for Cutaneous Melanoma on Dermatologists’ Clinical Management Decisions

May 2017 | Volume 16 | Issue 5 | Original Article | 428 | Copyright © May 2017


Aaron S. Farberg MD,a Alex M. Glazer MD,b Richard White MS,c and Darrell S. Rigel MD MSd

aDepartment of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY bNational Society for Cutaneous Medicine, New York, NY cIris Interactive System, Cody, WY dDepartment of Dermatology, NYU School of Medicine, New York, NY

Abstract

Importance: Current guidelines for cutaneous malignant melanoma (CMM) provide general recommendations regarding surveillance while indicating that management should be tailored to patients’ individual probability of recurrence. A 31-gene expression profile (31-GEP) test to predict metastatic risk has been previously validated, and classifies patients as either Class 1 (low risk) or Class 2 (high risk).

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Objective: To determine the impact of the 31-GEP test’s result on clinical decision-making.

Design, Setting, and Participants: Dermatology residents who attended a national educational conference were presented with clinical validity evidence for the 31-GEP. Respondents were given six CMM patient vignettes with descriptions of clinical features and answered questions about their willingness to recommend sentinel lymph node biopsy (SLNBx) or imaging based on each scenario. Additionally, respondents were asked to provide the Breslow thickness (BT), ranging from 0.7-1.5mm in 0.1mm increments, at which they would recommend SLNBx, imaging, or oncology referral.

Main Outcomes and Measures: The number of respondents who would recommend each management modality based upon three outcomes (no result, Class 1, or Class 2) was quantified. Differences between response groups were assessed using Fisher’s exact test.

Results: The majority of respondents (62%, 57%, and 55%, respectively) indicated a 1.0mm BT as the guiding modality, reflecting adherence to current guidelines. After inclusion of a Class 2 result, the BT used to guide SLNBx, oncology referral, and imaging was changed in 47%, 50% and 47% of the responses, respectively, with 95%, 84% and 97% of the cases, respectively, changed in a risk-appropriate direction (decreased BT). Based on a 31-GEP Class 1 or Class 2 result, risk appropriate recommendations were more likely to be made for each management modality tested in five of the six patient vignettes (P less than 0.05).

Conclusions and Relevance: The 31-GEP test had a significant and appropriate impact on management while remaining within the context of established guidelines.

J Drugs Dermatol. 2017;16(5):428-431.

BACKGROUND

Following a diagnosis of cutaneous malignant melanoma (CMM), patients are often guided for subsequent management by their dermatologist and national guideline recommendations.1,2 Based upon staging classification for CMM, guidelines recommend diagnostic tests and additional evaluation which may provide defined treatment protocols, surveillance, and follow-up. Unfortunately, these recommendations are often similar across several tumor stages in part because of the inability to precisely stratify different risk groups that may have markedly different outcomes. The push for personalized medicine has led to considerable advances in the guidelines and staging of CMM, including the recognition of the prognostic value of unique patient characteristics such as mitotic rate, ulceration presence, and sentinel lymph node biopsy (SLNBx) status.3 Technology has already been demonstrated to augment dermatologists’ clinical decision making for this tumor.4 Molecular-based techniques have been shown to provide additional information for CMM as has been noted in many other tumors. A 31-gene expression profile (GEP) test (DecisionDx-Melanoma, Castle Biosciences Inc., Friendswood, TX) was developed to predict whether a patient is at low-risk (Class 1) or high-risk (Class 2) for metastasis based on their primary CMM tumor biology.5,6 The prognostic accuracy of the 31-GEP was previously reported in several prospectively planned multicenter studies and contributes significant additional information when considered in combination with current AJCC staging criteria and guideline recommendations.5-8Although the 31-GEP has demonstrated reproducibility and clinical validity in assessing recurrence risk, another important aspect of molecular testing is clinical utility – the impact of the test results on clinical decision making. We sought to
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