Oral 3.01: Malignant thymoma incidence in a Chinese population
Chunxiao Wu
Background: Malignant thymoma is a rare malignancy of unknown etiology. Few population-based studies have described the patterns of the incidence. The object of the study is to describe the incidence of malignant thymoma and its trend in Shanghai, a representative sample of Chinese urban population, to provide basic information on the future clinical and prevention research.
Methods: Overall incidence and age specific incidence of malignant thymoma by sex and area (central downtown and suburb) in Shanghai in 2007–2011 were calculated to describe the current pattern. Annual percent change (APC) of age-standardized rates (ASR) of the population in central downtown from 1973 to 2011 was analyzed with Poisson regression.
Results: The overall incidence of malignant thymoma in 2007–2011 was 6.3 per 100,000 person-years (total 444 cases, 88 cases averagely per year) and the ASR was 3.6 per 100,000 person-years in Shanghai. The histopathology confirmed cases account for 76.6% (340 cases) of all the cases. Among the histopathology confirmed cases, 71.4% were thymic epithelial. The age-specific incidence increased with age except the age groups above 75. There is no significant difference of overall ASR between male and female. The ASR in central downtown is higher (39%) in suburb. In the central downtown area, the age-adjusted incidence rates in the male and the female were 1.2 and 0.6 per 100,000 person-years in 1973–1977, and increased to 4.7 and 3.8 per 100,000 person-years in 2007–2011. The annual percentage changes were 4.0% and 5.2% of male and female respectively during the past 39 years.
Conclusions: Malignant thymoma is extremely rare in Shanghai as well as in most other area of the world; however its incidence is increasing constantly in the recent 4 decades. Diagnosis improvement may explain part of the variation of the incidence, while further exploration on causation and risk factors are warrant.
Keywords: Malignant thymoma; Chinese; incidence; cancer registry
doi: 10.3978/j.issn.2072-1439.2015.AB062
