The role of HPV status in recurrent/metastatic squamous cell carcinoma of the head and neck.

Although the prognostic role of human papillomavirus (HPV) in locoregionally advanced squamous cell carcinoma of the head and neck (SCCHN) is well established, its prognostic and/or predictive role in recurrent/metastatic settings remains to be defined. Despite epidemic growth of HPV-positive oropharyngeal carcinoma, a low recurrence rate in HPV-positive patients results in a small number of patients entering clinical trials for recurrent and/or metastatic SCCHN. The consequent lack of statistical power and also significant data contamination by misclassification of HPV-positive patients leads to premature study conclusions. Even emerging data from the analysis of 2 randomized trials, SPECTRUM and EXTREME, do not provide enough evidence for any HPV-based therapeutic strategy. Many upcoming studies for locally advanced disease, including the ones with de-escalated strategies, will have an increasing number of patients with HPV. Optimal HPV testing strategies for reliable patient selection and HPV-driven therapeutic approaches will be essential. Here, we comprehensively review the existing data regarding HPV status and prognostic or predictive outcomes in recurrent/metastatic settings and discuss current promising studies and future directions that may help in the design of upcoming trials.