The effect of P53 expression and smoking/alcohol in P16(+) and P16(–) oropharyngeal carcinoma and risk classification: the Turkish Society of Radiation Oncology Head & Neck Study Group 01-002

Objective: The aim of this study is to categorize the risk groups of patients with oropharyngeal carcinoma (OPC) according to p16 and p53 status, smoking/alcohol consumption history, and other prognostic factors. Study Design: The immunostaining of p16 and p53 of 290 patients was retrospectively evaluated. The history of smoking/alcohol consumption of each patient was noted. p16 and p53 staining patterns were reviewed. The results were compared with demographic findings and prognostic factors. Risk groups have been classified for the p16 status of patients. Results: The median follow-up was 47 months (range 6-240). Five-year disease-free survival (DFS) rates for patients with p16 (+) and (–) were 76% and 36%, and overall survival rates were 83% vs 40%, respectively (HR = 0.34 [0.21-0.57], P < .0001), HR = 0.22 [0.12-0.40] P < .0001, respectively). p16(–), p53(+), heavy smoking/alcohol consumption, performance status; advanced T and N stages in patients with p16(–), and continuing smoking/alcohol consumption after treatment were found to be unfavorable risk factors. Five-year overall survival rates were 95%, 78%, and 36% for low, intermediate, and high-risk groups, respectively. Conclusions: The results of our study have shown that p16 negativity in patients with oropharyngeal cancer was found to be an important prognostic factor, especially for those with lower p53 expression and not smoking/consuming alcohol.