Treatment approaches of advanced cutaneous squamous cell carcinoma.

Common primary cutaneous squamous cell carcinoma (CSCC) accounts for 20% of keratinocyte cancers that is usually successfully treated with surgery or radiotherapy. In a minority of cases, CSCC lesions may progress to locally advanced or metastatic disease that may be difficult to be treated causing significant morbidity and mortality. Chemotherapies and targeted therapy with anti-epidermal growth factor receptor antibodies have been used off-label in small studies and case reports of advanced CSCC, but data are scarce and response short-lived. Recently, two PD-1 immune checkpoint inhibitors, cemiplimab and pembrolizumab, have been approved for the treatment of advanced CSCC; specifically the former can be administered in patients with locally advanced and metastatic tumours, while the latter in case of recurrent metastatic CSCC. The introduction of immune checkpoint inhibitors represents a breakthrough in the treatment of CSCC, since numerous clinical trials showed that these agents may provide remarkable clinical benefit with an acceptable safety profile, in a high-need population who had no standard of care. In addition, real-world studies are needed to validate the results observed in clinical trials and numerous clinical trials in the neoadjuvant or adjuvant setting are ongoing. Finally, further studies should investigate predictive biomarkers useful to better select patients to maximize the treatment efficacy.