Conference Coverage

31-GEP test predicts likelihood of metastasis for cutaneous melanoma



– The 31-gene expression profile test has met the highest level of evidence under the Strength of Recommendation Taxonomy (SORT) method as a prognostic marker for accurately predicting recurrence-free survival and distant metastasis-free survival and melanoma-specific survival, according to results presented by Bradley N. Greenhaw, MD, at a late-breaking research session at the annual meeting of the American Academy of Dermatology.

Dr. Greenhaw, a dermatologist affiliated with the North Mississippi Medical Center-Tupelo, and his colleagues pooled together 1,268 patients from the following studies that analyzed results from melanoma patients who had their disease classified with the 31-gene expression profile (31-GEP) test.

The 31-GEP test stratifies an individual’s likelihood of developing metastasis within 5 years as low and high risk. In the three studies, the test was used to identify tumors with low-risk (class 1A, class 1B), higher-risk (class 2A), and highest-risk (class 2B) melanoma based on tumor gene expression. In these individual studies, class 2B melanoma independently predicted recurrence-free survival (RFS), distant metastasis–free, and melanoma-specific survival.

Dr. Greenhaw and colleagues performed a meta-analysis of 1,268 patients with stage I through stage III melanoma from those three studies, using fixed and random effects weighting to account for study differences and heterogeneity, respectively. For class 2B tumors, they found a 2.96 increased risk for recurrent metastases and a 2.88 increased risk for distant metastases. The researchers also found no heterogeneity across the studies.

Melanoma-specific survival was not included in the meta-analysis because one paper did not contain any mortality events in class 1A melanoma patients.

“The meta-analysis demonstrated that the GEP test was able to accurately identify those melanoma patients who were at higher risk of metastasis, and we saw a consistent effect across multiple studies,” Dr. Greenhaw said.

Since publication of the 2019 JAAD paper, there were an additional 211 patients who met inclusion criteria and were included in an additional meta-analysis to determine whether inclusion of these patients affected the results. Dr. Greenhaw and colleagues found a 91.4% recurrence-free survival rate and a 94.1% distant metastasis–free survival rate for class 1A melanomas, compared with 45.7% and 55.5% , respectively, for class 2B tumors.

“You can see a big divergence,” Dr. Greenhaw said at the meeting. “Just by using this one test, it’s able to separate out melanomas that otherwise may be grouped in together under current AJCC [American Joint Committee on Cancer] staging,” he added. “The class 2B designation really did confirm a higher risk for recurrence in distant metastasis.”

The researchers used the SORT method to rate the quality of the data across all three studies. Level 1 evidence under the SORT method represents a systematic review or meta-analysis of good-quality studies and/or a prospective study with good follow-up, while an A-level recommendation represents good, quality evidence. Based on the meta-analysis results, the 31-GEP test meets level 1A evidence under the SORT method, Dr. Greenhaw said.

As a prognostic tool, 31-GEP has the potential to change how dermatologists manage their patients with regard to follow-up and adjuvant therapy. “It is being used not just as this novel test that gives us more information, it’s being used clinically,” said Dr. Greenhaw, who noted he regularly uses the 31-GEP test in his practice.

This is the first time that a meta-analysis has been performed for this test, he noted.

Dr. Greenhaw reports a pending relationship with Castle Biosciences.

SOURCE: Greenhaw BN et al. AAD 19. Session F055, Abstract 11370.

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