Sex Differences in Time Trends on Incidence Rates of Oropharyngeal and Oral Cavity Cancers in Hong Kong

Abstract

Worldwide studies have shown an increasing trend of oropharyngeal squamous cell carcinoma (OPSCC) but a decreasing trend of oral cavity cancers over the past 2 decades, particularly in developed countries with successful tobacco control. This trend has been attributed to the increase in the incidence of human papillomavirus (HPV)-associated OPSCC. The aim of this study was to examine sex differences in incidence trends of oropharyngeal and oral cavity cancers in Hong Kong from 1983 to 2014. Using data from the Hong Kong Cancer Registry from 1983 to 2014, age-standardized incidence rates for potentially HPV-associated sites (oropharyngeal) and non-HPV-associated sites (oral cavity) were calculated, stratified by sex and age groups. Joinpoint regression and an age-period-cohort model were used to assess incidence trends. A total of 1,972 cases of oropharyngeal cancer and 7,389 cases of oral cavity cancer were diagnosed from 1983 to 2014. The male/female ratios were 4.16:1 for oropharyngeal cancers and 1.63:1 for oral cavity cancers. A significant increasing trend was observed in oropharyngeal cancers from 1994 to 2014 (average annual percentage change = 2.66, P < .05). In contrast, a significant decreasing trend was observed in oral cavity cancers from 1983 to 1994 (average annual percentage change = -5.36, P < .05). The trends were more significant in men and in patients aged 45 to 69 years. A positive birth cohort effect was observed for oropharyngeal cancer in men. The rising trend of oropharyngeal cancer and decreasing trend of oral cavity cancer in Hong Kong from 1983 to 2014 are consistent with worldwide trends. Increase in high-risk sexual behaviors and oral HPV infection may influence the difference in trends.