1375Age-standardization to world population and under-estimation of oral cancer burden

Abstract

Abstract Background Age-standardization is common for adjustment of unequal population in different ages as it can influence cancer incidence. However, for planning healthcare services (including screening), one needs absolute magnitude since everyone needs intervention. This study assessed the effect of age-standardization on understanding the global differentials in magnitude of oral cancer. Methods Data on cancer incidence rates of oral cancers for 2008-2012, was obtained from the website of international agency for research on cancer for all 334 population-based cancer registries. Scatter plots were prepared between age-standardized and crude incidence rates to assess the ratio between them according to proportion of old people for all countries. Areas with high occurrence of oral cancer were identified. Results The ratio between age-standardized and crude incidence rate was >1 in countries with high proportion of older population (high-development-index countries), indicating an artificial widening of gap between incidence rates between countries due to age-standardization. Six areas had higher crude incidence rate among men than India. Based on the published estimates, the per-unit-population burden in Europe was 6.3% higher than India, while in USA it was merely 12.5% lower than India. Conclusions The perception of low burden of oral cancer in high-economy countries is artificial, brought about by common practice of age-standardization. Key messages Organization of oral cancer screening activities by countries with resources and expertise will provide much needed knowledge on its natural history and efficacy of control strategies.