Prevalence of Human Papillomavirus in Oropharyngeal Cancer: A Multicenter Study in Japan

Background: The incidence rates of oropharyngeal squamous cell carcinoma (OPSCC) have risen steadily in the USA and in northern Europe. These increases are thought to be a consequence of persistent infection with high-risk human papillomavirus (HPV) in OPSCC patients. HPV is an emerging etiologic factor in OPSCC. In Japan, the incidence of OPSCC has significantly increased over the last three decades. However, the population of HPV-positive OPSCC patients is currently unknown. We examined the nationwide trends with regard to HPV incidence in OPSCC patients at 21 specific sites, and examined the relationship between the presence of HPV and survival in OPSCC patients in Japan. Methods: Tumor samples were obtained from patients with OPSCC prior to treatment, and HPV infection was investigated by polymerase chain reaction (PCR). Hybrid Capture 2 (HC2) was also adopted for swab examination on the surface of fresh tumors. Results: HPV was detected by PCR in 79 (50.3%) out of 157 OPSCC patients. The clinical features of HPV-positive OPSCC were low differentiation, a tendency to involve the lateral wall, and high nodal staging. The sensitivity and specificity of HC2 were 93.7 and 96.2%, respectively, indicating its utility as a screening test. HPV-positive patients had significantly better overall survival and disease-free survival than HPV-negative patients.