The Inequitable Global Burden of Lip and Oral Cancers: Widening Disparities Across Countries

In light of continued innovation in cancer immunotherapy regimens and surgical management, no studies currently exist assessing the effect of these advances on global disparities in lip and oral cavity cancer disease burden. The purpose of this study is to characterize longitudinal trends in disease burden caused by lip and oral cavity cancers globally.

This retrospective, longitudinal cohort study extracted data on lip and oral cavity cancer disease burden from The Global Health Data Exchange for 1990-2017. The primary predictor variable was country human development index (HDI). The primary outcome variable was disease burden, measured by age-standardized disability-adjusted life years (DALYs) per 100,000 population, listed for each individual country. Additional variables assessed include country-level data on alcohol consumption and tobacco smoking. Concentration indices were also calculated. Mann-Whitney U and Kruskal-Wallis one-way analysis of variance tests with Bonferroni correction were utilized with a significance threshold of 0.008.

A total of 185 countries met inclusion criteria. Global age-standardized DALYs increased from 44.5 ± 35.7 to 51.1 ± 41.1 from 1990 to 2017. High HDI and medium HDI countries showed a +37.6% and +22.4% median increase in DALYs, respectively, which is significantly greater than very-high HDI (+3.8%) and low HDI countries (-0.5%) (P < .001). The concentration index for lip and oral cavity cancer became increasingly negative from -0.064 to -0.077 from 1990 to 2015. In 2017, disease burden was concentrated in South Asia and Eastern Europe.

High and medium HDI countries experienced a disproportionate growth in lip and oral cavity cancer disease burden. These findings may have resulted from increased life expectancy among these countries. Global and public health policy initiatives should focus on understanding the mechanisms driving these disparities with the goal of reducing disease burden globally.