Incorporation of the 40-Gene Expression Profile (40-GEP) Test to Improve Treatment Decisions in High-Risk Cutaneous Squamous Cell Carcinoma (cSCC) Patients: Case Series and Algorithm

Abstract

Cutaneous squamous cell carcinoma (cSCC) has become a significant public health issue due to its rapidly rising incidence and an estimated 1.8 million newly diagnosed cases annually. As with other cancers, treatment decisions for patients with cSCC are based primarily on a patient's risk for poor outcomes. There has been improvement in clinicopathologic factor-based risk assessment approaches, either through informal methods or ever evolving staging approaches. However, these approaches misidentify patients who will eventually have disease progression as low-risk and conversely, over classify patients as high-risk who do not experience relapse. To improve the accuracy of risk assessment for patients with cSCC, the 40-gene expression profile (40-GEP) test has been validated to show statistically significant stratification of a high-risk cSCC patient's risk of nodal or distant metastasis, independent of currently available risk-assessment methods. The 40-GEP test allows for a more accurate classification of metastatic risk for high-risk cSCC patients, with the aim to influence appropriate allocation of clinician time and therapeutic resources to those patients who will most benefit. The objective of this article is to present a treatment algorithm in which clinicians can easily integrate the results of the 40-GEP test into their current treatment approaches to tailor patient care based on individual tumor biology. The following modalities were considered: surveillance imaging, sentinel lymph node biopsy (SLNB), adjuvant radiation therapy (ART), and clinical follow-up. The authors have contributed their own cases for discussion as to how they have seen the beneficial impact of 40-GEP test results in their own practice. Overall, clinicians can identify risk-aligned treatment pathway improvements with the use of the 40-GEP test for challenging to manage, high-risk cSCC patients.

Keywords: 40-GEP; 40-gene expression profile; cSCC; clinician algorithm; cutaneous squamous cell carcinoma; metastasis; patient management; prognostic; risk-stratification.

Figure 1

A treatment algorithm for incorporation of 40-GEP test results into treatment decisions for a high-risk cSCC patient compared to current NCCN guideline recommendations. *Multidisciplinary board should be considered; **Choice of imaging technique dependent on number and type of high-risk factors.

Figure 2

Various stages of treatment for Case 1. (A) Presentation; (B) Mohs surgery; (C) Histological diagnosis; (D) Post-procedure.

Figure 3

Various stages of treatment for Case 2. (A) Presentation; (B) Mohs surgery; (C) Histological diagnosis; (D) Post-procedure.

Figure 4

Various stages of treatment for Case 3. (A) Presentation; (B) Mohs surgery; (C) Histological diagnosis; (D) Post-procedure.