Temporal trends, regional and socio-economic disparities of colorectal cancer burden in Cyprus

Abstract Background Colorectal cancer (CRC) is one of the main causes of mortality and morbidity worldwide and it is the third most common cancer in Cyprus. Previous studies have documented variations in CRC burden over time, across regions and area-based socio-economic deprivation. The aim of this study was to analyse the burden of CRC over time, across regions and area-based socio-economic deprivation in Cyprus for the time period 2000 to 2015. Methods A small area ecological study was performed, with census tracts as units of spatial analysis. The incidence and death date, sex and age of CRC were obtained from the population-based cancer registry of Cyprus. Indirect standardization was used to calculate the sex and age Standardize Incidence Ratios (SIRs) and Standardized Mortality Ratios (SMRs) of CRC while the smoothed estimates of SIRs and SMRs were derived from the Spatiotemporal Bayesian Poisson log-linear model. To investigate temporal trends in the association between area-based socioeconomic deprivation and CRC burden, we have used the national socio-economic index. Results The burden of CRC was rising over time. The CRC cumulative incidence increase from 243.7 in the time period 2000-2007 to 347.3 per 100,000 persons in the time period 2008-2015.There was also a more pronounced geographical variation in SIR and SMR in the time period 2008-2015. Four areas out of 369 had smoothed SIR>1.15 while twenty-six areas had smoothed SMR>1.15, with most of those areas located at the east coast of the island and around the capital city. There was a temporal trend in the socio-economic inequalities of CRC burden. The areas in the third and fourth quartile of the socio-economic index had 23% and 45% lower rates of CRC incidence, and 33% and 47% lower rates of CRC mortality in the period 2008-2015. Conclusions These findings could shape national prevention policies, such as the national screening program of CRC starting in 2025 and protection strategies for CRC mortality. Key messages • Colorectal cancer screening should be geographically targeted for efficient resource allocation. • Public health interventions to improve colorectal-specific mortality risk should be geographically targeted.