Composition of inflammatory cells regulating the response to concurrent chemoradiation therapy for HPV (+) tonsil cancer

Abstract

Human papillomavirus (HPV) (+) tonsil squamous cell carcinoma (TSCC) responds well to concurrent chemoradiation therapy (CCRT) and demonstrates a favorable prognosis. However, cases of HPV (+) TSCC-related death remain unresolved. We evaluated the distribution and prognostic value of inflammatory cells in HPV (+) TSCC. We reviewed the medical records of 53 patients who were diagnosed with TSCC. HPV (+) TSCC was confirmed using HPV DNA PCR and immunohistochemical p16 overexpression. The numbers of CD4 (+), CD8 (+), and CD68 (+) stained cells were used to evaluate peritumoral lymphocyte infiltration. Patients were divided into two groups according to the mean numbers of stained cells and the mean ratios of each cell type. HPV (+) was noted in 39 patients. During the follow-up period, 27 patients had no evidence of disease, 2 patients showed disease, and 10 patients died of disease. In this group, advanced T and N stages were not related to overall or disease-specific survival outcomes. The overall survival rate was affected by a high CD68 (+) (HR=19.8; P=0.040) and low CD8/CD4 ratio (HR=7.7, P=0.025). The disease-specific survival rate was affected by a high number of CD68 (+) cells (HR=15.2; P=0.03) and low CD8 (+)/CD4 (+) ratio (HR=3.3; P=0.04). The number of CD68 (+) cells and the distribution of cytotoxic or immunosuppressive T lymphocytes could be determining factors for CCRT outcomes in HPV (+) TSCC patients.