Twenty-year trend in colon cancer incidence in Tianjin, China

Purpose To describe and analyze the incidence trend of colon cancer in Tianjin, China from 1981 to 2000. Methods The primary data concerning cancer incidence was provided by Tianjin Cancer Registry (TCR). Among all the colon cancer cases reported, 68% were histologically confirmed, another 24% were diagnosed by clinical examination, and the last 8% were diagnosed by clinical symptoms. Cases in this study were constant inhabitants in urban Tianjin. All cancer cases were coded according to ICD-9. ICD code 153 represents colon cancer. The coding system remained unchanged during the 20 years. Incidence rates were calculated by five-year age-group as well as sex and year of diagnosis. Results During the years 1981–2000, the total number of colon cancer cases ascertained in urban Tianjin was 4954, including 2547 males and 2407 females. 67.9% of colon cancer cases occurred in the age group 55–79 and age specific incidence rate reached its peak in the age group 75–79. The mean incidence rate of colon cancer during the 20 years was 7.01/100,000 and this rate had been increasing constantly from 1981 to 2000. The average age at diagnosis was 62.4 years. An ascending trend was observed in the mean age at diagnosis of colon cancer from 1981 through 2000. However, as for the sex ratio, there was no clear trend exhibited. Conclusion The incidence trend of colon cancer during 1981–2000 in Tianjin increased. As there were no known particular risk factors seemed to be responsible for the observed increase, further research is warranted.