Long-Term Data From Patients Who Received Pembrolizumab in Locally Advanced or Metastatic Cutaneous Squamous Cell Carcinoma.

Nonmelanoma skin cancer (NMSC) is one of the most common cancers worldwide and cutaneous squamous cell carcinoma (CSCC) is the second most prevalent type of the NMSCs. Most often, the prognosis is good when treated with surgery with or without additional radiotherapy; however, in about 1% of patients, the disease is inoperable or advanced with no curative potential. We present four cases in which the immune checkpoint inhibitor pembrolizumab was given to patients with advanced CSCC. Three patients obtained complete response (CR) with an ongoing duration of response with a follow-up time of 60, 78, and 79 months and one who achieved stable disease (SD) as the best response. Two of the patients discontinued treatment after eight cycles of pembrolizumab due to side effects. Immunotherapy with a programmed death protein 1 (PD-1) inhibitor is an approved therapy for these patients today. The successful treatment with long-term duration of response of these three out of four patients supports the use of a PD-1 inhibitor as a primary treatment for locally advanced and metastatic CSCC.