Study: Gene Expression Test IDs Best Patients for Adjuvant Radiation Therapy

Test provides additional prognostic value to current risk assessment methods.

New research suggests that a 40-gene expression profile (40-GEP) test can help identify the best patients for adjuvant radiation therapy for cutaneous squamous cell carcinoma (cSCC). 

The study, whose results were presented at ASDS 2023, consisted of two merged validation cohorts for the 40-GEP test which were confirmed as eligible for testing and had a successful 40-GEP test result (n=954). After exclusions, 920 patients participated and were matched on clinical risk factors stratified by adjuvant radiation therapy status. The authors used random sampling of adjuvant radiation therapy status pairs and bootstrapping to avoid dropping any qualified patients and allow generalizability to the cSCC high-risk population. 

The matched cohort analysis identified one particular class, Class 2B cSCC, as the only factor in the study that identified patients that would benefit from adjuvant radiation therapy, in contrast to clinicopathologic risk factors or risk assessment systems. The researchers also performed extensive control analyses to demonstrate the robustness of the results by systematically dropping a single risk factor from propensity matching, and then testing for radiation benefit. 

The decision whether or not to treat given cSCC patients with adjuvant radiation therapy is clinically challenging, with factors such as estimated clinical risk of local recurrence and disease progression, risk/benefit ratio, patient preference, and access/economic factors all contributing to the decision process," Sarah T. Arron, MD, PhD, of Peninsula Dermatology in Burlingame, CA, and the study's lead author, said in an oral abstract presentation of the results. "The findings indicate that the 40-GEP test can be utilized to help clinicians identify patients most likely to benefit from adjuvant radiation therapy and assist in decisions regarding disease managementy. 

Reference

Arron S, Canueto J, Siegel J, et al. Association of a 40-gene expression profile (40-GEP) with risk of metastatic disease progression of cutaneous squamous cell carcinoma (cSCC) and benefit of adjuvant radiation therapy (ART). Oral abstract presentation. Presented at: American Society for Dermatologic Surgery (ASDS) 2023 Annual Meeting; Nov. 2-5, 2023, Chicago.