Spatio-temporal analysis of the incidence of colorectal cancer in Guangzhou, 2010-2014.

INTRODUCTION: Colorectal cancer (CRC) is a common type of neoplasm. This study examined the spatio-temporal distribution of the CRC incidence in Guangzhou during 2010-2014. METHODS: Colorectal cancer incidence data were obtained from the Guangzhou Cancer Registry System. Spatial autocorrelation analysis and a retrospective spatio-temporal scan were used to assess the spatio-temporal cluster distribution of CRC cases. RESULTS: A total of 14,618 CRC cases were registered in Guangzhou during 2010-2014, with a crude incidence of 35.56/100,000 and an age-standardized rate of incidence by the world standard population (ASRIW) of 23.58/100,000. The crude incidence increased by 19.70% from 2010 (32.88/100,000) to 2014 (39.36/100,000) with an average annual percentage change (AAPC) of 4.33%. The AAPC of ASRIW was not statistically significant. The spatial autocorrelation analysis revealed a CRC incidence hot spot in central urban areas in Guangzhou City, which included 25 streets in southwestern Baiyun District, northwestern Haizhu District, and the border region between Liwan and Yuexiu Districts. Three high- and five low-incidence clusters were identified according to spatio-temporal scan of CRC incidence clusters. The high-incidence clusters were located in central urban areas including the border regions between Baiyun, Haizhu, Liwan, and Yuexiu Districts. CONCLUSIONS: This study revealed the spatio-temporal cluster pattern of the incidence of CRC in Guangzhou. This information can inform allocation of health resources for CRC screening.

[A 1:1 matched case-control study on the interaction between HBV, HCV infection and DNA repair gene XPC Ala499Val, Lys939Gln for primary hepatocellular carcinoma].

OBJECTIVE: To evaluate the interaction between environmental factors, HBV/HCV infections and DNA repair gene XPC exon 8 Ala499Val, exon 15 Lys939Gln on related risks to primary hepatocellular carcinoma (PHC). METHODS: A 1:1 matched case-control study was conducted in Shunde city, Guangdong province. The genotypes of Ala499Val and Lys939Gln were detected by polymerase chain reaction restrictive fragment length polymorphism (PCR-RFLP) analysis, and gene-environment interactions were analyzed by conditional logistic regression. RESULTS: Among people infected by HBV with non- or at least one mutant gene of Ala499Val carriers, the risk of PHC significantly increased, with ORs as 3.768 (95%CI: 1.137 - 12.485) and 3.667(95%CI: 1.122 - 11.981) respectively. With non- or at least one mutant gene of Lys939Gln, the risk was increasing with ORs as 6.778 (95%CI: 2.025 - 22.688) and 3.152 (95%CI: 1.062 - 9.351) respectively. In those with HCV infection, non- or at least one mutant gene of Ala499Val might increase the risk with ORs as 2.955 (95%CI: 0.587 - 14.869), 1.085(95%CI: 0.307 - 3.839) respectively. However, when compared to the ones with no mutant gene of Lys939Gln among the same research subjects, those carrying at least one gene may decrease the risk, with OR lowered from 4.197 (95%CI: 0.870 - 20.243) to 0.887 (95%CI: 0.228 - 3.448). But the interactions between HBV infection, HCV infection and XPC genes were not statistically significant. CONCLUSION: Among people infected by HCV, the mutant gene of Ala499Val had the tendency to lower the risk of PHC, and the mutant gene of Lys939Gln also appeared the same in the population with either HBV infection or HCV infection in Shunde, Guangdong. Another study with large samples should be performed to analyze the interactions among environments-genes.