Thyroid Cancer Incidence Continues to Rise in Young, Hispanic and African-American Populations in the United States

Presentation Number: SH04-6
Date of Presentation: April 3rd, 2017

Anupam Kotwal*1, Juan Pablo Brito1 and Archie Bleyer2
1Mayo Clinic, Rochester, MN, 2Oregon Health and Science University


Background: Thyroid cancer incidence has been consistently increasing in the United States for the last 3 decades, mainly due to a surge in the diagnosis of small papillary thyroid cancers. Morris et al, have recently shown that since 2010 the incidence of thyroid cancer has, however, plateaued; from an annual percent increase (APC) of 6.7% from 1998 to 2009 to 1.75% from 2010 to 2012 (1). This trend change occurred for tumors regardless of their size. Acknowledging the study limitation, Morris et al, suggested that shifts in medical practice may be driving this trend (1). Whether or not this trend deceleration exists across age, gender and race groups is, however, unclear.

Aim: We sought to examine the trend of thyroid cancer in different age and gender subgroups.

Methods: Age adjusted incidence, including APC in incidence and trends in age-adjusted rates were obtained from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER 18) program (2). Analyses were conducted for the period from 2000 to 2013 using the publically available online interactive tool (SEER*Explorer).

Results: From 2000 to 2013, thyroid cancer incidence increased from 7.4 to 14.5 cases per 100,000 population with an APC of 6.7% from 2000-2009 (p < 0.05) and 2.4% from 2010 to 2013 (p < 0.05). In Hispanics and African-Americans, thyroid cancer incidence has continuously increased, with an APC of 4.7% (p < 0.05) and 5.1% (p < 0.05) respectively, whereas for non-Hispanic whites, the APC decelerated from 7.1% (p < 0.05) before 2009 to 2.2% after 2009. Stratified by age group, the only group in which the rate of thyroid cancer continued to accelerate at an unchanged rate is those 20 years of age or less. On the other hand, persons 75 years of age or older did have stabilization of their rising incidence after 2009, with an APC of 1%. Females and males have similar deceleration of their overall rates after 2009, with APCs if 2.3% and 2.8%, respectively. When subgroups were combined based on their association with acceleration or deceleration rates, the group with the highest APC without any deceleration evidence was Hispanic females between the age of 20 and 49 years.

Conclusion: Our findings are consistent with recently published analyses suggesting that thyroid cancer incidence is leveling off in the US. Our analysis, however, shows that trend deceleration mainly occurred in non-Hispanic Whites and in older populations, whereas the rate of thyroid cancer continuously increased among the young, Hispanic and African-American populations. These findings are consistent with recent reports demonstrating that thyroid cancer is the 2nd most common cancer among Hispanic females, female adolescents and young adults. Drivers for these variations in thyroid cancer trends are unknown and require further investigation. Likewise, future analysis will demonstrate if this change in thyroid cancer incidence will persist.


Disclosure: AB: Consultant, Sigma-Tau Pharmaceuticals. Nothing to Disclose: AK, JPB