title: [Time trends of the incidence of thyroid cancer in urban Guangzhou, 2000-2011].
abstract: OBJECTIVE
  To investigate the incidence and trends of thyroid cancer in urban areas of Guangzhou, 2000-2011.
  
  
  METHODS
  Total of 2 957 new cases with a coverage population of 45 699 522 person-years diagnosed as thyroid cancer in 2000-2011 in urban areas of Guangzhou were extracted from the population-based data base of Guangzhou cancer registry, among which 649 were males and 2 308 were females with a coverage population of 23 391 743 person-years and 22 307 779 person-years, respectively. The crude incidence, Chinese age-adjusted incidence rate and world age-adjusted incidence rate were calculated. Time trends of different gender and age groups were examined using Joinpoint Regression Program.
  
  
  RESULTS
  There were a total of 2 957 cases diagnosed as thyroid cancer during 2000-2011 with a sex ratio of 1: 3.56. World age adjusted incidence rates of thyroid cancer in urban areas of Guangzhou increased dramatically from 2.99/100 000 in 2000 to 9.13/100 000 in 2011 with an increase rate of 204.73%. Annual percentage change (APC) was 10.5% (P < 0.001). The APC in world age adjusted incidence rates of thyroid cancer were 8.6% (P < 0.001) for male and 10.9% (P < 0.001) for female, resulting in a total increase of 169.45% (from 1.32/100 000 to 3.54/100 000) for male and 214.64% for female (from 4.73/100 000 to 14.87/100 000). The mean age of onset of thyroid cancer was significantly different between the males and females. The incidence rate of thyroid cancer in females aged 45-59 group (19.56/100 000) reached the highest one.While in males, it was increasing gradually with the age, the incidence increased from 0.74/100 000 in aged 15-19 to 9.48/10 000 in aged of 85 years above. The APC was significant in 20-59 age groups in both males (12.2%) and females (13.4%) (P < 0.001).
  
  
  CONCLUSIONS
  The incidence rate of thyroid cancer increased rapidly in urban areas of Guangzhou. The prevention and treatment of thyroid cancer should be focused on 20-59 age groups.
authors.affiliation: School of Public Health and Tropical Medicine, Southern Medical University,Guangzhou 510515, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.forename: Guozhen
authors.initials: G
authors.lastname: Lin
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Email:wxb70@126.com.
authors.forename: Xianbo
authors.initials: X
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D002681:China; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms; D014505:Urban Population; D055815:Young Adult