Distinct Outcomes of Oropharyngeal Squamous Cell Carcinoma Patients after Distant Failure According to p16 Status: Implication in Therapeutic Options.

INTRODUCTION: Recent modifications in the epidemiology of oropharyngeal squamous cell carcinoma (OSCC) have led to the increase of Human papillomavirus (HPV) related metastatic head and neck cancer patients with high life expectancy even at advanced stage, low comorbidity and still restricted systemic therapy opportunities. In the recent era of ablative therapies' development, oligometastatic HPV OSCC patients are indubitably good candidates for intensified treatment. However, data related to outcomes after optimised management of metastatic sites are dramatically missing. MATERIALS AND PATIENTS: In our cohort of 186 unselected consecutive OSCC patients treated with curative intent at our institution between 2009 and 2013, we analysed the incidence, treatment and outcomes of distant metastatic (DM) failure according to p16 status. RESULTS: After a median follow-up of 4.2 years (95% CI: 3.8-4.4) from primary diagnosis of OSCC, 21/95 p16- patients (22.1%) vs. 8/91 (8.8%) p16+ patients presented DM failure with a median interval of 11 (range 0-46) and 28 months (range 0-71), respectively (p = 0.10). Overall survival (OS) after DM failure was significantly higher in p16+ patients with a two-year OS rate of 75% and 15% for p16+ and p16-, respectively (p = 0.002). In eight HPV-related metastatic patients, three underwent ablative lung metastasis treatment and are still complete responders four to five years later. CONCLUSION: This study highlights distinct outcomes of metastatic HPV-related OSCC patients emphasised by three long-term complete responders after lung ablative treatment. In patients with high life expectancy and limited tumour burden, the question of ablative treatment such as metastasectomy or stereotactic ablative radiotherapy (SBRT) should be addressed.