Purpose: P16 is the single most important prognostic variable in oropharyngeal squmaous cell cancer (OPSCC), surpassing traditional prognostic factors for both cancer specific survival and recurrence free survival. Disease stage has no prognostic significance in p16-positive OPSCC1 .OPSCC patients are often reported as one group in articles and studies regardless that within the subsites of the oropharynx there are possible differences regarding P 16 prevalence and incidence of disease recurrence. We further analysed P16 prevalence in different sub-sites of oropharynx and rates of recurrence in Local population.
Methods: We identified patients presented at Head and Neck Multidisplinary meeting from 2011-2012 at Gold Coast University Hospital. Patients with Oropharyngeal SCC were included in study. Retrospective analysis of P 16 status at different subsites of oropharyngeal cavity and recurrence was carried out.
Result: 80 patients diagnosed with oropharyngeal cancer presented at Gold Coast University Hospital Head and Neck Multidisciplinary meeting from 2011-2012 were identified. 36 patients (45%) were diagnosed with base of tongue cancer (BOT), 32 (40%) with tonsil and 12 (15%) patients with other oropharyngeal sites. Of these 80 patients P16 status was available for 76 (95%) patients. In the BOT group 25 biopsies (69%) were P 16 positive , in tonsil group 15 ( 46%) and in other oropharyngeal group 9 (75%) . Recurrence rates in P 16 positive were 5% in BOT/ other OPSCC and 6 % in tonsillar SCC at the time of study.
Conclusion: P 16 prevalence in our group was lowest in tonsillar OPSSC (46%) and recurrence rates were similar in all subsites of oropharynx. Larger study with longer follw up is required to analyses outcomes at different subsites of p16 positive OPSCC. Our study was limited by small number and retrospective nature.