A clinical impact study of dermatologists’ use of the 23- or 35-gene expression profile tests to guide surgical excision and enhance management plan confidence
Authors: Farberg Aaron S , Ahmed Kelli L , Rackley Briana B , Siegel Jennifer J , Russell Brooke H , Rogers Jason H , Kurley Sarah J , Goldberg Matthew S 
Published: March 2023

Purpose: To understand how dermatologists utilize the results from ancillary diagnostic gene expression profile (dGEP) testing with the 23- or 35-GEP tests to determine optimal patient management strategies. Study: Dermatologists who regularly treat patients with difficult-to-diagnose melanocytic lesions who had previously initiated dGEP testing at least 3 times were eligible to complete the questionnaire in this Institutional Review Board-approved study. There were 24 randomized vignettes presented covering a spectrum of cases with diagnostic/clinical uncertainty such as atypical melanocytic proliferation, dysplastic nevus with regression, deep penetrating melanocytic neoplasm, and atypical intraepidermal melanocytic proliferation. Respondents were provided with a clinical impression and diagnosis in the context of a narrative pathology report with/without a re-excision recommendation; cases were also described without (baseline) and with a dGEP test result (likely benign or likely malignant). Anonymous responses concerning the patient management plan including excision and follow-up recommendations and confidence were captured. Statistical significance was calculated by nonparametric Wilcoxon signed-rank test with continuity correction. Results: In total, 32 dermatologists (84% in a private practice setting) completed the survey, with 50% indicating additional dermatopathology specialization. Approximately 44% of respondents indicated they performed 10-50 biopsies of melanocytic lesions per month, and 31%, greater than 100 per month. When dGEP results were provided, there was an overall increase in management plan confidence, regardless of which dGEP result was provided (benign dGEP 26.2%, malignant dGEP 24.7%). Also, when dGEP results were provided, changes in surgical excision recommendations were statistically significant in 75% of scenarios tested (p < 0.02). Clinical impact was assessed by quantifying the directional shift in treatment in relation to the dGEP result. With regard to excision recommendations across vignettes, benign dGEP results prompted 29.7% of clinicians to decrease their margins or forgo excision altogether. Malignant dGEP results prompted 63.5% of clinicians to increase their surgical excision recommendations. Appropriate alterations in patient follow-up frequency were observed, with 18.8% of clinicians reducing and 43.2% increasing follow-up frequency for patients receiving benign or malignant dGEP results, respectively. Conclusion: The addition of dGEP testing to diagnostic scenarios with confounding clinical features and uncertainty in optimal management prompted important changes in recommendations regarding the need for excision, appropriate margins, and follow-up-frequency. Overall, dGEP tests help to guide clinical decision-making for dermatologists in a variety of otherwise diagnostically ambiguous or clinicopathologically discordant scenarios.