Impact of Gene Expression Profile Testing on the Management of Squamous Cell Carcinoma by Dermatologists

October 2019 | Volume 18 | Issue 10 | Original Article | 980 | Copyright © October 2019

Rebeca Teplitz BA,ª Giselle Prado MD,B Graham H. Litchman DO MS,B Darrell S. Rigel MD MSc

ªMedical Student, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, NY

BClinical Research Fellow, National Society for Cutaneous Medicine, New York, NY

cClinical Professor, Department of Dermatology, NYU School of Medicine, New York, NY

a longer follow-up interval for all vignettes. (Figure 1) Similarly, a Class 2 cSCC-GEP result was associated with a statistically significant increase in the proportion who would recommend shorter follow-up interval for all vignettes.


The results of this study indicate that additional information provided by GEP can improve management for cSCC patients. In most situations, a lower risk cSCC-GEP result was associated with a significant reduction in recommendations for SLNBx, adjuvant radiation therapy and chemotherapy/immunotherapy, as well as a tendency to lengthen the recommended follow-up interval. Conversely, a higher risk result was associated with a significant increase in recommendations for SLNBx, adjuvant radiation therapy and chemotherapy/immunotherapy, as well as a shorter follow-up interval in most cases. As these patients are at a higher risk for development of subsequent metastases and/ or local recurrence, they would likely benefit from close monitoring. For these reasons, the results from this study suggest that cSCC-GEP test results could lead to decreased morbidity and mortality.

In the field of melanoma, GEP tests are currently being utilized to identify high-risk patients and determine their need to receive adjuvant radiation, chemotherapy, and other forms of therapy.12 These tests are impacting physician management decisions for melanoma patients. The present study shows that GEP testing has the potential to improve clinical decision-making for cSCC cases as well.

More than one third of participants stated they did not use any system to stage their cSCC patients. This represents a clear knowledge gap and opportunity to improve clinical practice. The cSCC-GEP test may act as an additional piece of information, that in combination with a traditional staging system such as AJCC, could better optimize patient outcomes. A previous study of GEP in melanoma showed that adding GEP results to AJCC staging had an additive positive effect on prognostic accuracy.13 Future studies are warranted to determine if the cSCC-GEP test can have a similar impact.

A new immune therapy, Cemiplimab (PD-1 inhibitor), has been FDA-approved and shown to be efficacious for management of metastatic and locally advanced cSCC.10 Current staging systems are mainly histologic in nature, and genomic testing may more effectively identify high risk cases that would benefit from treatment with Cemiplimab. cSCC-GEP testing can aid in targeting this expensive therapy to high risk patients, while minimizing adverse effects for patients with lower risk disease who may not benefit from the drug.

Limitations to this study include the possibility that the clinical vignettes used are not complete representations of real-world patient cases. Moreover, this study used a cross sectional design and therefore, the results cannot be used to make inferences about causation. Additionally, the sample of dermatologists attending the national conference may not accurately represent the larger population of dermatologists practicing across the United States.


The results of this study suggest that the information provided by the cSCC-GEP test can significantly impact dermatologist management recommendations, including the decision to perform a SLNBx and recommendations for adjuvant radiation therapy and chemotherapy/immunotherapy, while remaining within the context of established guidelines. Further, study physicians utilized the information from cSCC-GEP to alter management in the risk appropriate direction. This indicates significant theoretical clinical utility and suggests that the improved prognostic information provided could potentially lead to more efficient resource allocation and targeted treatment for cSCC patients.


Dr. Rigel served as a consultant to Castle Biosciences Inc. Dr. Litchman participated in a research fellowship, which was partially funded by Castle Biosciences Inc. Dr. Prado participated in a research fellowship, which was partially funded by Castle Biosciences Inc.

Funding Source: The National Society for Cutaneous Medicine (a 501(c)3 not-for-profit entity) funded this study. The group has received unrestricted educational grants from Castle Biosciences Inc.


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