Primary cutaneous melanoma is a malignant skin condition. It causes lesions and leads to the incidence of skin cancers. Patients who are at a high risk of developing regional lymph node metastasis can experience fatal outcomes. The CP‐GEP model is in use to accurately identify low-risk patients. This study attempts to validate the model. The melanoma gets categorized into T1, T2, T3, and T4 based on lesion sizes. This study aims to endorse the CP-GEP model (Clinicopathological and Gene Expression Profile) in independent, Dutch patients. 

A total of 210 patients were a part of the study. They were over 18 and underwent SLNB between 2007 and 2017. The model combines 8 target gene expressions with age and Breslow thickness. Researchers calculated the performance metrics for high and low risk of nodal metastasis, and the SLNB pathology result is the gold standard for this study.   

About 94 or 45% of patients had T2, while 70 or 33% showed T3 melanoma, and about 56 or 27% tested positive for SLNB. The nodal metastasis in T1, T2, T3, and T4 patients was 0%, 30%, 54%, and 16%. The model had a 90.5% negative predictive value (NPV) at 95% confidence interval. The NPV for T1, T2, and T3 patients were 100%, 89.3%, and 75%. 

The CP-GEP predicted a high risk for all T4 patients. This non-invasive validation tool accurately identifies low-risk subjects. It has the potential to reduce SLNB procedures for melanoma.