Systemic Immunotherapy for Advanced Cutaneous Squamous Cell Carcinoma

Advanced (i.e., unresectable) cutaneous squamous cell carcinoma (cSCC) is a rare condition with a dismal prognosis. Although less than 5% of cSCC patients develop metastases or local recurrence after complete excision, advanced cSCC is difficult to treat. These conditions tend to develop in elderly patients, although, at times, metastases are noted in middle-aged patients. Once metastasis occurs in cSCC, the 10-year survival rates fall to less than 20% for patients with regional lymph node involvement and less than 10% for patients with distant metastases, indicating that cSCC can be difficult to treat effectively when it is advanced. Traditionally, platinum-based therapy has been considered as a conventional option for advanced cSCC. It is efficacious to some degree, but the toxic effects of the combination treatments often prohibit their use in elderly patients. It has been a decade since the development of epidermal growth factor receptor (EGFR) inhibitors as agents that are less toxic. However, evidence regarding systemic therapy for advanced cSCC is limited because of a lack of high-quality prospective studies. Remarkably, the US Food and Drug Administration (FDA) approved an anti-PD-1 antibody treatment (cemiplimab) for the treatment of patients who are not candidates for curative surgery or curative radiation. It will be a promising treatment option for these types of rare conditions.