Current status of systemic therapy for recurrent and/or metastatic squamous cell carcinoma of the head and neck.

Head and neck squamous cell carcinoma (HNSCC) is now the seventh most common cancer worldwide. The median overall survival for patients with recurrent and/or metastatic (R/M) HNSCC remains <1 year despite modern systemic chemotherapy and targeted agents. Palliative systemic therapy for patients with R/M HNSCC typically includes a platinum-based doublet, with an understanding that the increase in efficacy compared with single agents is primarily related to improved response rate, and not survival. Till date, the only systemic therapy regimen to demonstrate survival superiority over platinum-5-fluorouracil (5-FU) doublet is platinum, FU, and cetuximab. Epidermal growth factor receptor inhibitors, including monoclonal antibodies and tyrosine kinase inhibitors, have achieved only a modest success in R/M HNSCC. Immunotherapy represents an attractive treatment option for R/M HNSCC, with encouraging preliminary data from studies involving immune checkpoint inhibitors (e.g., pembrolizumab, nivolumab) and toll-like receptor agonists (e.g., motolimod). Given the poor prognosis of R/M HNSCC, enrollment of patients into clinical trials to investigate novel systemic agents, is necessary for further improvement of oncologic outcomes in this patient population.