Common features in recurrent HPV positiveoropharyngeal cancer patients– a retrospective cohort study

Abstract: Introduction Oropharyngeal cancer (OPC) is increasing in incidence today. The cancer isdivided in to two subtypes, positive for Human papilloma virus (HPV) or negative. Previousstudies have concluded that the HPV positive type entails a better prognosis. Despite this,HPV positive patients experience aggressive recurrences and this study wanted to investigaterisk factors connected to these recurrences.  Aim This study aimed to investigate potential risk factors for recurrence in patients treated forHPV positive OPC. Methods The study was performed as a retrospective patient medical record study. Patientsdiagnosed with OPC between the years of 2007 to 2018 were included. The predeterminedpotential risk factors for recurrence (gender, smoking habits, age, tumor stage, type oftreatment) were compared for the HPV positive groups, the patients that experiencedrecurrences and the patients who did not.  Results 160 patients were diagnosed with HPV+ OPC during the time period and 22experienced a recurrence. A statistically significant difference for male sex (p=0.041) and foradvanced T stage (p=0.004), respectively, was observed. Smoking habits (p=0.108) and age(p=0.148) turned out to be insignificant. Most of the patients were treated according to thesame standard scheme, which differed depending on the tumor being a tonsil- (externalradiotherapy 68 Gy) versus a tongue base cancer (external radiotherapy 40.8 Gy,brachytherapy 35 Gy and a neck dissection).  Conclusions Patients with male sex and advanced T stage of the primary tumor showed ahigher risk of experiencing a recurrence. Further research using prospective design are neededto investigate the impact of patient-, tumor- and treatment characteristics on recurrence riskfor patients with HPV positive OPC.