OBJECTIVETo analyze the geographic spatial patterns and risk areas of main digestive system cancers in Yiwu city.

METHODSNewly diagnosed cases of esophageal, gastric and colorectal cancer during 2010-2014 were obtained from Yiwu Center for Disease Control and Prevention (CDC). The household registration population data in 2013 were obtained from public security bureau. Hierarchy clustering and partitioning regionalization method was used to generate geographic units. Global Moran's I was used to evaluate whether cancer incidence was significantly clustered in space, Anselin Local Moran's I was used to identify statistically significant hot spots, cold spots, and spatial outliers, and Spatial Scan Statistics was implemented to analyze the relative risk of cancers in different areas.

RESULTSThe 5-year average incidence of esophageal, gastric and colorectal cancers were 9.99/100 000, 34.01/100 000 and 31.46/100 000, respectively. Males showed significantly higher incidence than females. The incidence was heterogeneous throughout the study area. Spatial Scan analysis revealed that southern Yiwu presented a significantly higher male esophageal cancer (=1.78) and gastric cancer (=1.87) risk. The central area of Yiwu showed a significantly lower female esophageal cancer risk (=0.00) and male stomach cancer risk (=0.63) and the northern Yiwu exhibited a significantly lower female colorectal cancer risk (=0.48).

CONCLUSIONSThe incidence of main digestive tract cancers shows a heterogeneous distribution in Yiwu city.