Immunohistochemical p16 expression in the prognosis of patients with sinonasal squamous cell carcinoma

In sinonasal squamous cell carcinoma (SNSCC), the prognostic relevance of p16INK4a (p16) expression has been reported rarely. This study aims to examine the immunohistochemical expression of p16 and investigate the possibility of p16 as a prognostic factor for SNSCC. The medical records of 173 individuals with SNSCC between 2010 and 2022 were retrospectively reviewed. The researchers examined patients' demographics, p16 status, staging, tumor histological subtypes, treatment details, recurrence, metastasis, and survival outcomes. p16 was found in 22.0% (38/173) of SNSCC patients, and there was no difference between inverted papilloma-SNSCC (19.6%) and de novo SNSCC (23.0%). p16 status did not correlate with all the cases' age, gender, clinical stage, or therapy features. p16-positive patients had a considerably superior 5-year overall survival (OS) rate (80.7% vs. 57.5%, p=0.039) and a slight tendency in progression-free survival (PFS) rate (68.1% vs. 52.0%, p=0.15), except in stage T4b cases. In maxillary sinus lesions, p16-positive SNSCC had a better 5-year OS (87.4% vs. 49.2%, p=0.03) rate and PFS (79.1% vs. 40.7%, p=0.01) rate than p16-negative SNSCC. Among patients without skull base involvement (82.9% vs. 57.7%, p=0.037) or orbital invasion (86.9% vs. 57.3%, p=0.02), p16-positive SNSCC confers benefits in OS rates more than p16-negative SNSCC. Immunohistochemical p16 expression may be a predictive predictor in individuals with maxillary sinus SCC, non-T4b stage, without skull base involvement, and without orbital invasion.