Global variations and socioeconomic inequalities in lifetime risk of lip, oral cavity, and pharyngeal cancer: a population-based systematic analysis of GLOBOCAN 2022

Background: In 2021, the World Health Organization (WHO) identified poor oral health as a major health expenditure burden. While lip, oral cavity, and pharyngeal cancers (LOCP) are an important group of diseases threatening oral health, there have been limited studies assessing global variations in lifetime risks (LR) according to socioeconomic inequalities. Materials and methods: We obtained national incidence and mortality estimates of LOCP in 185 countries from the GLOBOCAN database of the International Agency for Research on Cancer (IARC), corresponding all-cause mortality, population data, and the Human Development Index (HDI, with higher values indicating superior socioeconomic level) through the United Nations, alongside oral health-related data through WHO and INDEXBOX. LR were calculated using the adjusted multiple primary method. Results: In 2022, the global LR of developing and dying from LOCP were 0.92% (95% CI: 0.92%–0.92%) and 0.48% (95% CI: 0.48%–0.48%), respectively, with the highest burden associated with cancers of the lip and oral cavity. The LR of being diagnosed with LOCP or dying from the disease were 2.24 (95% CI: 2.22–2.25) and 2.30 (95% CI: 2.27–2.33) times higher among males relative to females. The highest LR for lip and oral cavity, salivary gland, oropharynx, and hypopharynx cancers were largely concentrated in Australia/New Zealand, Europe, and North America; whereas nasopharynx cancer was more frequent in parts of Asia and Africa. The LR of developing and dying from LOCP were positively associated with HDI, dental healthcare expenditure, areca nut consumption, the availability of refined sugar, and early screening for oral diseases, and negatively associated with the prevalence of severe periodontal disease. Although the LR of LOCP decreased with age, the rate of decline was relatively slow until the age of 50, and even at age 70, there remained non-negligible risks. Conclusion: Global variations in the LR of developing and dying from LOCP by subsite, sex and age reveal significant disparities by world region, socioeconomic levels and oral healthcare factors.