[Time trends and pathological characteristics of thyroid cancer in urban Beijing, 1995 - 2010]

To describe the incidence trends and to access the histological changing patterns of thyroid cancer in urban areas of Beijing.

Total of 4883 new cases diagnosed as thyroid cancer in 1995-2010 in urban areas of Beijing were extracted from the population-based data base of Beijing cancer registry, among which 1185 were males and 3698 were females with a coverage population of 56 143 454 person-years and 54 430 655 person-years, respectively. Incidence, age adjusted incidence, annual percentage change (APC) and gender specific incidence change of different histology patterns during last 16 years were calculate.

There were 4883 cases diagnosed as thyroid cancer during 1995 - 2010 with the sex ratio of 1:3 (1185 males and 3698 females). Incidence rate of thyroid cancer in urban areas of Beijing increased dramatically from 1.55/100 000 (97/6 245 016) in 1995 to 9.90/100 000 (768/7 758 759) in 2010 with an increase rate of 538.71%. After adjusted by world population, the standardized incidence rate increased from 1.27/100 000 in 1995 to 6.96/100 000 in 2010 with a 12.12% annual percentage change (APC = 12.12%, P < 0.05). Among males, incidence rate increased from 0.85/100 000 (27/3 185 669) to 4.58/100 000 (179/3 912 458) with an increase rate of 438.82%. After adjusted by world population, the standardized incidence rate of males increased from 0.68/100 000 in 1995 to 3.19/100 000 in 2010 with an 11.09% annual percentage change (APC = 11.09%, P < 0.05). Among females, the incidence rate increased from 2.29/100 000 (70/3 059 347) to 15.31/100 000 (589/3 846 301) with an increase rate of 568.56%. After adjusted by world population, the standardized incidence rate of females increased from 1.89/100 000 in 1995 to 10.82/100 000 in 2010 with a 12.48% annual percentage change (APC = 12.48%, P < 0.05). Incidence rate ranked 18th and 12th in 1995 among males and females, respectively; while it ranked 14th and 5th in 2010 respectively. Among 4883 cases, 4594 cases were confirmed histologically as primary tumor accounting for 94.08% of total cases. Papillary carcinoma was the most common subtype accounting for 77.31% (3775/4883) of total cases. Among all the pathological types of thyroid cancer, the proportion of papillary carcinoma has risen from 51.55% (50/97) in 1995 to 87.63% (673/768) in 2010. However, the proportion of the follicular carcinoma decreased from 5.15% (5/97) to 1.69% (13/768).

Incidence of thyroid cancer in urban areas of Beijing keeps increasing which is mainly due to the rising of papillary carcinoma. Risk factors of papillary thyroid cancer should be focused on when strategies for thyroid cancer prevention and control are conducted.