Objective: China has experienced significant changes in economy, society, environment and lifestyle during past 20 years. Currently, cancer death is ranked number one cause of death in urban China. It is important to study the epidemiological characteristics of the disease, risk factors and prevention to provide directions for anti-cancer strategy in the country.
Methods: Since 1981, Tianjin Cancer Registry has been collecting data on all residents of Tianjin who develop cancer. Epidemiological characteristics were analyzed by descriptive epidemiologic methods. Risk factors and random clinical trial were studied using ecology and case-control study. Secondary prevention of breast cancer was explored by screening among 130,000 women.
Results: During 1981-2000, more than 140,000 new cancer cases were diagnosed among the residents of urban Tianjin. Cancer incidence cases increased by 3.3% per year; lifetime risk for cancer increased from one seventh in 1981 to one forth in 2000. For all cancers combined, the crude incidence rate was increased by 1.99% a year, while age-adjusted incidence was relatively stable. The result of linear regression analysis between population median age and cancer incidence indicated that the increases are mainly attributable to growing aging populations. Five-year survival rate was increased by 79.91% from 19.81% during 1981-1985 to 35.64% during 1996-2000. During the past 20 years, the incidence of lung cancer was the highest among all cancer sites. Cancers of colorectal, lung, brain, male kidney, female breast, pancreas and ovary have showed apparent increasing trends. Cancers of the esophagus, stomach, liver and women cervix uteri have declined substantially. Ecological studies suggest that tobacco use, second-hand smoking, improvement in living conditions and kitchen ventilation may be associated with the stabilization of lung cancer incidence. Molecular epidemiological studies indicated that smokers who carried with the genotypes of CYP1A1MspI variant, GSTMs null had increasing susceptibility to lung cancer. Results of breast cancer screening among 130,000 women indicated that 10-year survival rate was improved by screening from 64.5 to 73.3%. Randomized clinical intervention trial of Tamoxifen (TAM) among 414 breast cancer patients who were ER positive found that 5-year survival rates were 88.73% and 80.11% for TAM and control groups, respectively. TAM seemed to lower tumor recurrence.
Conclusions: Cancer remains to be a huge health burden in China. Cancer patterns in urban China have gradually been changing over the past 20 years, which start to resemble those in the developed countries while keeping some characteristics of developing countries. This change in pattern indicates the possible role of lifestyle change due to rapid economic development in China. Although efforts to prevent cancer have been taken over past the 20 years, cancer intervention is still a big challenge in China.
98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA