Stereotactic body radiotherapy for recurrent oropharyngeal cancer - influence of HPV status and smoking history.

PURPOSE: HPV status and smoking history stratifies patients into 3 distinct risk groups for survival following definitive chemoradiotherapy. Local-regional recurrences are common patterns of failure across all 3 risk-groups. SBRT±cetuximab has emerged as a promising salvage strategy for unresectable locally-recurrent, previously-irradiated head-and-neck cancer (rHNC) relative to conventional re-irradiation±chemotherapy. However the influence of HPV and smoking remains unknown in the setting of re-irradiation. METHODS/MATERIALS: Patients (n=30) with rHNC of the oropharynx salvaged with SBRT±cetuximab from August 2002 through August 2013 were retrospectively reviewed; HPV status was determined based on p16 staining of primary pathology. RESULTS: At a median follow-up of 10months for surviving patients, the mean overall survival for all patients was 12.6 months. HPV positivity was a significant predictor of overall survival (13.6 vs. 6.88 months, p=0.024), while smoking status did not significantly impact overall survival (p=0.707). CONCLUSION: HPV status remains a significant predictor of overall survival in the re-irradiation setting with HPV positive rHNC demonstrating superior overall survival following salvage SBRT±cetuximab.