Velez MA, et al. - Among patients treated by salvage radiation therapy for local-regional recurrences and second primary cancers of the head and neck arising in a previously irradiated field, the prognostic significance of human papillomavirus (HPV) status was assessed. It was determined that the favorable prognostic significance of HPV possibly extended to patients treated by re-irradiation. The obtained data indicated that this biomarker could be useful for risk stratification in this setting.