Li Xie1, Suna Wang2, Ying Qian2, Sinong Jia2, Jie Wang2, Lei Li2, Weituo Zhang1, Herbert Yu3, Pingping Bao4, Biyun Qian5. 1. Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China; Clinical Research Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China. 2. Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China. 3. Cancer Epidemiology Program, University of Hawaii Cancer Center, 701 Ilalo Street, Honolulu, HI, 96813, USA. 4. Department of Cancer Control and Prevention, Division of Non-communicable Disease Prevention and Control, Shanghai Municipal Center for Disease Prevention and Control, Shanghai 200336, People's Republic of China. Electronic address: baopingping@scdc.sh.cn. 5. Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China; Shanghai Clinical Research Promotion and Development Center, Shanghai Hospital Development Center, Shanghai 200041, People's Republic of China. Electronic address: qianbiyun@sjtu.edu.cn.
Abstract
OBJECTIVE: We aimed to examine secular trends of thyroid cancer incidence and mortality and to estimate the proportion of thyroid cancer cases potentially attributable to overdiagnosis. METHODS: Data on thyroid cancer cases from 1973 to 2015 were obtained from Shanghai Cancer Registry. Average annual percent changes (AAPCs) were evaluated by Joinpoint regression analysis. Age, period, and birth cohort effects were assessed by age-period-cohort model. Overdiagnosis of thyroid cancer cases was estimated from the difference between observed and expected incidences using the rates of the Nordic countries as reference. RESULTS: From 1973 to 2015, the number of thyroid cancer cases was 23,117, and 75% were female. Age-standardized rates were seven to eight-fold higher in 2013-2015 than in 1973-1977. Compared with relatively stable mortality, thyroid cancer incidence was dramatically increased from 2002 to 2015 in both genders with significant trends (men: AAPC =21.84%, 95%CI: 18.77%-24.98%, P<0.001; women: AAPC=18.55%, 95%CI: 16.49%-20.64%, P<0.001). The proportion of overdiagnosis has been gradually increased over time, rising from 68% in 2003-2007 to more than 90% in 2013-2015, and the increasing pattern appeared to be similar between men and women. CONCLUSION: An increasing gap between thyroid cancer incidence and mortality was observed in Shanghai and overdiagnosis has contributed substantially on the rise of incidence, which calls for an urgent update on the practice of thyroid examination.
OBJECTIVE: We aimed to examine secular trends of thyroid cancer incidence and mortality and to estimate the proportion of thyroid cancer cases potentially attributable to overdiagnosis. METHODS: Data on thyroid cancer cases from 1973 to 2015 were obtained from Shanghai Cancer Registry. Average annual percent changes (AAPCs) were evaluated by Joinpoint regression analysis. Age, period, and birth cohort effects were assessed by age-period-cohort model. Overdiagnosis of thyroid cancer cases was estimated from the difference between observed and expected incidences using the rates of the Nordic countries as reference. RESULTS: From 1973 to 2015, the number of thyroid cancer cases was 23,117, and 75% were female. Age-standardized rates were seven to eight-fold higher in 2013-2015 than in 1973-1977. Compared with relatively stable mortality, thyroid cancer incidence was dramatically increased from 2002 to 2015 in both genders with significant trends (men: AAPC =21.84%, 95%CI: 18.77%-24.98%, P<0.001; women: AAPC=18.55%, 95%CI: 16.49%-20.64%, P<0.001). The proportion of overdiagnosis has been gradually increased over time, rising from 68% in 2003-2007 to more than 90% in 2013-2015, and the increasing pattern appeared to be similar between men and women. CONCLUSION: An increasing gap between thyroid cancer incidence and mortality was observed in Shanghai and overdiagnosis has contributed substantially on the rise of incidence, which calls for an urgent update on the practice of thyroid examination.