HPV-Associated Oropharyngeal Cancer: A Growing Dilemma

Human papillomavirus (HPV) is the root cause of more than 5% of cancers, including all cervical cancers and a substantial percentage of cancers at other sites.¹ An estimated 63% of oropharyngeal cancers (OPCs) are caused by HPV; HPV type 16, the most common form, accounts for 90% to 95% of HPV-associated OPCs.^2-7 More than 90% of OPCs are squamous cell cancers (SCCs) and are significantly more likely to be HPV-positive compared to other head and neck squamous cell cancers (HNSCC).^4,7

Partly due to successful tobacco cessation efforts, the incidence of HPV-negative OPC is in decline; however, HPV-positive OPC rates are increasing with no sign of abating (Table 1).^4-6,8 This is largely a result of differences in exposure behaviors—such as smoking and number of sexual partners—in middle-aged adults compared with their older birth cohorts.⁸

Compared with HPV-negative OPC, HPV-positive OPC patients are disproportionately younger, male, nonsmokers, and nondrinkers. Although diagnosis at stage III/IV is common, with multi-node metastasis present, survival rates are better. On examination, tumors tend to be poorly differentiated, nonkeratinizing, and with basaloid morphology.^5-7,13At current rates, OPC will become the leading HPV-associated cancer in the United States by the year 2020, surpassing the annual number of cervical cancers.^5,6 Similar trends have been observed in other Western countries.⁵

Table 1. Incidence Rates of HPV-negative and HPV-positive Oropharyngeal Cancers⁶