P16 immunohistochemistry alone is a better prognosticator in tonsil cancer than human papillomavirus in situ hybridization with or without p16 immunohistochemistry

Conclusions: p16 immunohistochemistry (IHC) status correlated with less exposure to smoking and/or alcohol in Korean patients with locally advanced tonsillar squamous cell carcinoma (TSCC), and was an independent prognostic factor for survival. Objective: TSCC is more likely to be human papillomavirus (HPV)-positive than other head and neck squamous cell carcinoma (HNSCC) subtypes. The objective of this study was to ascertain the HPV status of TSCC in Korean patients and to determine its relationship with clinical parameters and prognosis. Methods: The locally advanced TSCCs of 79 patients who were treated between 2000 and 2008 were tested by p16 IHC and HPV in situ hybridization (ISH) with a tissue microarray. Results: Sixty-three patients (80%) were positive for p16 IHC, while 54 (68%) were positive by HPV ISH. p16 IHC status correlated significantly with lower exposure to smoking and alcohol (p < 0.05) but did not correlate with T and N stage classification, histological differentiation, age, or gender. The p16-positive group had a significantly higher 5-year overall survival rate in comparison with the p16-negative group (78% vs 63%, hazard ratio (HR) = 0.347, 95% CI = 0.14, 95% Cp = 0.025). p16 IHC was a favorable independent prognostic factor for overall survival, even after adjustment for age and T stage (HR = 0.283, 95% CI = 0.103, 95% p = 0.015).