[Spatial clustering analysis and trend of liver cancer death rate in Shandong province, 1970-2013].

Objective: To explore the spatial clustering and trend of liver cancer mortality in different counties of Shandong province from 1970 to 2013, and provide scientific basis for the development of liver cancer prevention and control plan. Methods: Cancer mortality data were obtained from Shandong Death Registration System and three national death cause surveys in China. Mortality rate and age adjusted mortality rate were used to describe the trend of liver cancer in different years. Difference decomposing method was applied to estimate the contribution of demographic and non-demographic factors to the change of mortality. Software ArcGIS 10.2 was used for spatial analysis, and software SaTScan 9.4 was used for spatial clustering analysis on liver cancer mortality. Results: From 2011 to 2013, the crude mortality rate of liver cancer (29.89/100 000) in Shandong increased by 208.00% and 35.37% respectively compared with that during 1970-1974 (9.72/100 000) and 1990-1992 (22.08/100 000) and was similar to that during 2004-2005 (30.44/100 000). While age standardized mortality rate (ASMR) increased first and then decreased. The ASMR during 2011-2013 (12.62/100 000) increased by 60.97% compared with that during 1970-1974 and decreased by 22.38% and 21.81% compared with that during 1990-1992 and 2004-2005, respectively. According to the difference decomposition analysis on liver cancer mortality in different years, the contribution of population factors to the liver cancer mortality rate increased from 3.38% during 1990-1992 to 29.36% during 2004-2005 and 46.16% during 2011-2013. However, the contribution of non-population factors to the increase of liver cancer mortality decreased. According to the spatial distribution of liver cancer mortality, the crude mortality rate of liver cancer in different counties were quite different, ranging from 9.33/100 000 to 65.33/100 000. Using the spatial scanning statistical software to analyze the spatial clustering of liver cancer mortality, multi areas with high mortality rate of liver cancer were found, and they were mainly distributed in Jiaodong peninsula from 2011 to 2013, covering 20 counties (cities, districts) in Qingdao, Yantai and Weihai. The risk of liver cancer mortality in this area was 1.54 times higher than that in other areas. The spatial clustering distribution of liver cancer mortality during 1970-1974 was significantly different from that during 2011-2013, the areas with high mortality rate during 1970-1974 were mainly distributed in central and western Shandong. Conclusions: There were significant temporal and spatial distribution changes in the mortality rate of liver cancer in Shandong from 1970 to 2013. According to these trends and their geographical and spatial distribution, we should further explore the risk factors of liver cancer, and formulate feasible and area specific prevention and control measures for liver cancer.