Long-Term Survival and Recurrence in Oropharyngeal Squamous Cell Carcinoma in Relation to Subsites, HPV, and p16-Status.

Long-term survival data in relation to sub-sites, human papillomavirus (HPV), and p16INK4a (p16) for patients with oropharyngeal squamous cell carcinoma (OPSCC) is still sparse. Furthermore, reports have indicated atypical and late recurrences for patients with HPV and p16 positive OPSCC. Therefore, we assessed long-term survival and recurrence in relation to oropharyngeal subsite and HPV/p16 status. A total of 529 patients with OPSCC, diagnosed in the period 2000-2010, with known HPVDNA and p16-status, were included. HPV/p16 status and sub-sites were correlated to disease-free and overall survival (DFS and OS respectively). The overexpression of p16 (p16+) is associated with significantly better long-term OS and DFS in tonsillar and base of tongue carcinomas (TSCC/BOTSCC), but not in patients with other OPSCC. Patients with HPVDNA+/p16+ TSCC/BOTSCC presented better OS and DFS compared to those with HPVDNA-/p16- tumors, while those with HPVDNA-/p16+ cancer had an intermediate survival. Late recurrences were rare, and significantly more frequent in patients with p16- tumors, while the prognosis after relapse was poor independent of HPVDNA+/-/p16+/- status. In conclusion, patients with p16+ OPSCC do not have more late recurrences than p16-, and a clear prognostic value of p16+ was only observed in TSCC/BOTSCC. Finally, the combination of HPVDNA and p16 provided superior prognostic information compared to p16 alone in TSCC/BOTSCC.