Recurrent and Metastatic Head and Neck Cancer: Mechanisms of Treatment Failure, Treatment Paradigms, and New Horizons.

Head and neck cancer is a deadly disease with over 500,000 cases annually worldwide. Metastatic head and neck cancer accounts for a large proportion of the mortality associated with this disease. Many advances have been made in our understanding of the mechanisms of metastasis. The application of immunotherapy to locally recurrent or metastatic head and neck cancer has not only improved oncologic outcomes but has also provided valuable insights into the mechanisms of immune evasion and ultimately treatment failure. : This review paper will review our current understanding of biological mechanisms of treatment failure and metastasis. Published and ongoing clinical trials in the management of metastatic head and neck cancer will also be summarized. : A narrative review was conducted to address the current understanding of the mechanisms of treatment failure and current treatment paradigms in recurrent and metastatic head and neck carcinoma. Our understanding of treatment failure in this disease is rapidly evolving. Immunotherapy represents a valuable new tool in the fight against recurrent and metastatic head and neck squamous cell carcinoma. Integrating patient and tumor specific data via artificial intelligence and deep learning will allow for a precision oncology approach, thereby achieving better prognostication and management of patients with this deadly disease.