Human Papillomavirus-Associated Oropharyngeal Cancer: Defining Risk Groups and Clinical Trials.

Human papillomavirus-associated oropharynx cancer (HPVA-OPC) is rapidly increasing in incidence and has unique epidemiologic, molecular, and biologic characteristics. Despite being recognized as having superior prognosis, current evidence does not support less intense therapy compared with HPV-negative OPC. Current combined modality therapies confer a significant risk of morbidity, and patients with HPVA-OPC have a younger median age. These patients, therefore, live longer with the adverse effects of treatment, and this spurs the development of treatment deintensification trials that attempt to decrease treatment-related morbidity without compromising efficacy. Many radiation and chemotherapy de-escalation trials are underway. Minimally invasive surgical techniques are also being evaluated. It is important to identify the ideal patient group for treatment deintensification and to define prognostic risk groups to avoid undertreating the poorer-risk subset in HPVA-OPC, and validated biomarkers are needed to identify patients with the best prognosis. Significant smoking exposure mitigates the favorable prognosis of HPVA-OPC. Currently, less intense treatment is an option only in the setting of clinical trials, and patients with HPVA-OPC should be offered clinical trial options whenever they are available. Finally, recognition of novel therapeutic targets and signaling pathways is critical to the development of new treatment strategies that are desperately needed for patients with poor risk and those with recurrent and metastatic disease.