Comparison of twenty-year cancer incidences between two large metropolitan cities in north and south China Free

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Objectives: Tianjin and Shanghai are two of the biggest cities in the northern and southern part of China, respectively.Dietary habits, lifestyles and environmental exposures are substantially different between the long-term residents in the two regions. Cancer registries have been established in both cities for more than 20 years. We compared cancer incidences in Tianjin and Shanghai during 1981 through 2000 in order to generate leads for etiological research and preventive intervention.

Methods: Using cancer incident reports in Tianjin Cancer Registry and population data in the city, we calculated cancer incidence rates in a 3-year interval for each 5-year age group and age-standardized rates adjusted with the world population in 1985 year. Cancer incidence rates in Shanghai were extracted from data published by Shanghai Cancer Registry. Cancer diagnoses were coded according to ICD-9 (World Health Organization, 1977).

Results: For all cancers combined, the crude incidence rates (CR) for males and females were both increased significantly in Tianjin during 1981-2000. The age-standardized incidence rates (ASR), however, were decreased for both men and women from 189.7 to 173.0 per 100,000, with an average decline of 0.2% a year, and from 154.2 to 150.7 per 100,000, with an average decline of 0.1% a year, respectively. The CR was also increased in Shanghai for all cancers. The ASRs were decreased in men from 245.5 to 231.4 per 100,000, an annual decline of 0.5%, but increased in women from 153.8 to 177.1 per 100,000, an annual increase of 0.6%. Overall, the cancer incidences were higher in men than in women. Between 1981 and 2000, the incidences of colorectal, pancreas, bladder, and brain cancers were increased, while esophagus, stomach, liver and female cervical cancers were declined in both Tianjin and Shanghai. Male kidney and prostate cancers as well as female breast and ovarian cancers also rose rapidly. Lung cancer was the number malignancy for men in both places. It also ranked number one for women in Tianjin, while breast cancer was the top one in Shanghai. In 2000, lung, stomach, liver, colon and esophagus were the top five cancers in men, and in women, the five leading cancers were lung, breast, colon, stomach and liver. The orders of these leading cancers, however, were slightly different between Tianjin and Shanghai.

Conclusions: Crude cancer incidences have been increasing dramatically in both North and South China during 1981-2000. These increases are mainly attributable to growing aging populations in the country as age-adjusted incidences were relatively stable. Cancer patterns have changed over the past 20 years, declining in cancers from upper digestive system and rising in “western” cancers. This change in pattern indicates the possible role of lifestyle change due to rapid economic development in China.