Objective: To explore whether there existed spatial and familial aggregation in gastric cancer in Yangzhong City of Jiangsu Province.
Methods: Using the data collected from cancer incidence registry and report system in Yangzhong City and newly designed investigation for double Y nuclear family, a genetic epidemiological study was conducted in 448 nuclear pedigrees with gastric cancer and 437 control pedigrees, involving 5 242 family members.
Results: Chi square test of goodness-of-fit for Poisson distribution showed there was difference between real incidence rate of gastric cancer in all townships and towns in Yangzhong and expected distribution, with chi(2) = 191.07, P < 0.001. The highest rate was in Sanyao, Changhong and Youfang townships, which was 2.2 times higher as that in the areas with low-incidence rate. Prevalence rate of gastric cancer was significantly higher in the siblings (5.42%) and parents (8.65%) of the probands, than that in siblings and parents of their spouses (4.94% and 3.20%, respectively). Prevalence rate of gastric cancer in the offspring with both parents suffered from gastric cancer was the highest, 22.58%. Test for goodness-of-fit of binominal distribution showed that there was significant difference between observed number and expected number of pedigrees with gastric cancer, with P < 0.0001.
Conclusion: There was not only significantly spatial aggregation of gastric cancer in Yangzhong City, but also familial aggregation, which coincided with a mode of multi-genetic inheritance based on preliminary results and laid a foundation for exploring the difference in gentic susceptibilities and environmental factors for gastric cancer in Yangzhong City.