The prognosis of HPV-associated metastatic pharyngeal patients by primary and distant site.

Objectives: Human papillomavirus (HPV) positivity is a favorable prognostic factor in the general population of head and neck squamous cell carcinoma (HNSCC) patients. However, its impact on the survival of metastatic HNSCC of pharynx (mHNSC-P) patients is unclear. This study aims to investigate the associations between HPV status and survival in mHNSC-P patients.

Methods: 735 mHNSC-P patients diagnosed at first presentation from 2010 to 2016 were retrieved from the Surveillance, Epidemiology and End Result database (SEER). Chi-Squared test, univariate and multivariate cox proportional hazards model, Kaplan-Meier analysis, and log-rank test were applied to compare HPV-positive and -negative mHNSC-P patients.

Result: Using univariate cox proportional hazards analysis, HPV status, primary site, T stage, treatment and distant metastatic site correlate with the overall survival (OS) and disease-specific survival (DSS) in mHNSC-P patients. Multivariate cox regression analysis shows that HPV-positive mHNSC-P patients experienced significantly better OS (HR: 0.62 CI: 0.51-0.76, p < 0.001) and DSS (HR: 0.73 CI: 0.58-0.91, p < 0.01) as compared to HPV-negative mHNSC-P patients. Subgroup analysis indicates that HPV-associated OS and DSS benefits exist in patients with metastatic HNSCC of oropharynx (mHNSC-OP) but not in patients with metastatic HNSCC of non-oropharynx (mHNSC-non-OP). Among mHNSC-OP patients, HPV positivity confers disease-specific survival benefit in patients with oligometastatic rather than polymetastatic patients. Furthermore, HPV associated OS and DSS advantages in mHNSC-OP with lung metastasis was observed.

Conclusion: HPV-positive mHNSC-OP patients with lung metastasis show better survival than HPV-negative mHNSC-OP patients, providing key information to guide patient treatment approaches.