Trends in thyroid cancer mortality among adults in the United States and Puerto Rico, 1999–2021.

e18023 Background: Thyroid cancer is a leading endocrine malignancy characterized by rising global incidence. Despite advancements in diagnosis and therapy, it continues to impose a significant public health burden. This study evaluates thyroid cancer mortality trends in the United States and Puerto Rico from 1999 to 2021, stratified by sex, race/ethnicity, and geographic factors. Methods: We analyzed CDC WONDER Multiple Cause-of-Death data to estimate age-adjusted mortality rates (AAMR) for thyroid cancer (ICD-10 Code: C73) among adults. Crude mortality rates (CMRs) and AAMR per 100,000 were calculated. Joinpoint regression was used to estimate annual percentage change (APC) and average annual percentage change (AAPC) with 95% confidence intervals (CIs), stratified by sex, race, ethnicity, and census regions. Results: From 1999 to 2021, 38,642 thyroid cancer-related deaths were reported among adults in the United States and Puerto Rico. Of these, 21,649 (56.0%) were females and 16,993 (44.0%) were males. By race and ethnicity, the highest number of deaths occurred among Non-Hispanic (NH) Whites (29,212; 75.6%), followed by Hispanics (3,745; 9.7%), NH Blacks (3,532; 9.1%), and NH Asians (1,905; 4.9%). The South had the highest number of deaths by Census region (13,192; 34.2%), while the Northeast had the lowest (7,498; 20.0%). Conclusions: Thyroid cancer mortality shows significant rising rates among men, a disproportionately high burden among NH Asian/Pacific Islanders, and notable regional increases in the South and Midwest. These evolving disparities underscore the need for targeted clinical interventions and equitable healthcare access to address sex-specific and geographic inequities in endocrine cancer outcomes. Trends related to thyroid cancer mortality among adults in the United States and Puerto Rico, 1999 to 2021. Variable Deaths (n) AAMR (95% CI) 1999 AAMR (95% CI) 2021 Male 16,993 0.68 (0.63 to 0.75) 0.79 (0.74 to 0.84) Female 21,649 0.70 (0.65 to 0.75) 0.77 (0.73 to 0.82) NH White 29,212 0.67 (0.63 to 0.71) 0.75 (0.72 to 0.79) NH Blacks 3,532 0.69 (0.57 to 0.84) 0.75 (0.64 to 0.86) NH Asians 1,905 0.98 (0.69 to 1.34) 0.87 (0.72 to 1.04) Hispanics 3,745 1.06 (0.85 to 1.31) 0.92 (0.81 to 1.05) Northeast 7,498 0.74 (0.66 to 0.83) 0.60 (0.54 to 0.68) South 13,192 0.64 (0.58 to 0.7) 0.78 (0.72 to 0.84)