Abstract
Background: Exploring disease in space and time enhances our understanding of true needy areas. The present study aimed to spatiotemporal mapping of colorectal cancer (CRC) and gastric cancer (GC) incidence using Bayesian models and space-time scan statistic in Hamadan Province from 2010 to 2019.
Study Design: An ecological time-series study.
Methods: The CRC and GC cases were obtained from Hamadan cancer registry. The crude standardized incidence ratio (SIR) was calculated for each county per year. Hierarchical Bayesian space-time models were fitted to estimate adjusted SIRs. Space time clusters analysis were performed using space-time scan statistic.
Results: A total of 1,864 CRC cases and 2,340 GC cases were included in the analyses. The central counties including Hamadan (smoothed SIR range2010-2019: 1.24, 1.28) and Tuyserkan (1.01, 1.24), exhibited higher than expected cases of CRC. Northern counties such as Razan (1.19, 1.51) and Kabudarahang (1.21, 1.42), along with Nahavand in the south (0.98, 1.53), also showed higher than expected cases of GC. The most spatio-temporal cluster of CRC involved Hamadan and Tuyserkan occurring between 2015 and 2019 (relative risk = 1.82, P<0.001). The most spatio-temporal cluster of GC involved Nahavand from 2010 to 2011 (relative risk = 1.87, P<0.001).
Conclusion: Spatiotemporal inequality for CRC and GC exist in Hamadan province over the past decade. The findings may aid to reduce cancer disparities and allocating effective resources at the appropriate region and time in the future.