Expert opinion

Keratinocyte carcinoma (KC), formerly known as non-melanoma skin cancer (NMSC), includes basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and their precursors such as actinic keratosis (AK) and Bowen’s disease, an in situ form of cSCC [ 1 ]. cSCC is the second most common form of skin cancer after BCC, accounting for approximately 20% of KC [ 2 , 3 ]. Determining its precise incidence is challenging; however, cSCC represents a growing public health concern, with recent data showing a sustained increase in incidence in Germany [ 4 ]. Known risk factors are fair or light skin, male sex, cumulative ultraviolet radiation exposure, history of severe sunburns, older age, systemic immunosuppression (including organ transplantation and hematologic malignancies such as chronic lymphocytic leukemia), smoking, and genetic predisposition such as xeroderma pigmentosum [ 5 , 6 , 7 ].