Temporal Trends in Papillary and Follicular Thyroid Cancer Incidence from 1995 to 2019 in Adults in Denmark According to Education and Income

Polycystic ovary syndrome and risk of differentiated thyroid cancer: A nationwide, register-based cohort study based on Danish health data

OBJECTIVES

To evaluate the association between polycystic ovary syndrome (PCOS) and the risk of differentiated and papillary thyroid cancer.

METHODS

We included all individuals assigned female at birth and born during 1962-1996 in Denmark. Information on vital status, PCOS- and cancer diagnoses, and covariates were attained from various Danish nationwide registers. Personal identification numbers assigned to all individuals at birth are used throughout all registers and allows accurate individual-level data linkage. Using Cox regression analysis, we estimated hazard ratios (HRs) and 95 % confidence intervals (CI) for differentiated thyroid cancer (overall and separately for papillary thyroid cancer) according to diagnosis of PCOS.

RESULTS

The final study cohort comprised 990 850 individuals. During follow-up, we identified 980 individuals with incident differentiated thyroid cancer, of whom 15 were previously diagnosed with PCOS. We found no increased rate of differentiated thyroid cancer for individuals with PCOS (HR=1.52, 95 % CI:0.91-2.53). However, a positive association for women diagnosed with thyroid cancer within 10 years after PCOS diagnosis (HR=3.81, 95 % CI:1.90-7.66) compared to women without PCOS was seen. Of note, none of the individuals were diagnosed with differentiated thyroid cancer within the first three years following the PCOS diagnosis. Results were similar for papillary thyroid cancer.

CONCLUSION

We found no association when investigating the association between PCOS and differentiated and papillary thyroid cancer overall, though we did find a positive association in the first 10 years after PCOS diagnosis. Even this large study was limited by the low number of cancer cases in exposed individuals.

Impact of American Thyroid Association’s Revised Cancer Management Guidelines on Thyroid Cancer Incidence Trends: A Retrospective Cohort Study, 2000–2020

Background: The past four decades have seen a steady increase in thyroid cancer in the United States (US). This study investigated the impact of the American Thyroid Association (ATA)’s revised cancer management guidelines on thyroid cancer incidence trends and how the trends varied by socioeconomic, histologic, geographic, and racial and ethnic characteristics from 2000 to 2020. Methods: We used data from the Surveillance, Epidemiology, and End Results (SEER) database to identify thyroid cancer cases diagnosed among US patients between 2000 and 2020. We employed joinpoint regression software to fit, assess, and compare thyroid cancer incidence trends over time stratified by socioeconomic status (SES), histologic type, geographic location, and race/ethnicity. Results: Between 2000 and 2009, there was an average annual increase of 5.8% in thyroid cancer incidence (average annual percent change (AAPC): 5.8, p < 0.05). Subsequently, there was a modest rise (AAPC: 1.1, p < 0.05) from 2010 to 2015, followed by a significant annual decrease of 4.8% from 2016 to 2020 (AAPC: −4.8, p < 0.05). The joinpoint regression models identified prominent inflection points around 2009 and 2015, aligning with the years of the ATA’s cancer management revisions. These intricate dynamics in thyroid cancer incidence trends from 2000 to 2020 were shaped by SES and histologic, geographic, and racial/ethnic factors. Conclusions: Thyroid cancer incidence trends over the past two decades can be partially explained by the changes in thyroid cancer screening and management recommendations. These findings underscore the importance of cancer management strategies and highlight the need for targeted interventions to address disparities in thyroid cancer incidence across minority demographic groups.

Impact of American Thyroid Association's Revised Cancer Management Guidelines on Thyroid Cancer Incidence Trends: A Retrospective Cohort Study, 2000-2020

Background: The past four decades have seen a steady increase in thyroid cancer in the United States (US). This study investigated the impact of the American Thyroid Association (ATA)'s revised cancer management guidelines on thyroid cancer incidence trends and how the trends varied by socioeconomic, histologic, geographic, and racial and ethnic characteristics from 2000 to 2020. Methods: We used data from the Surveillance, Epidemiology, and End Results (SEER) database to identify thyroid cancer cases diagnosed among US patients between 2000 and 2020. We employed joinpoint regression software to fit, assess, and compare thyroid cancer incidence trends over time stratified by socioeconomic status (SES), histologic type, geographic location, and race/ethnicity. Results: Between 2000 and 2009, there was an average annual increase of 5.8% in thyroid cancer incidence (average annual percent change (AAPC): 5.8, p < 0.05). Subsequently, there was a modest rise (AAPC: 1.1, p < 0.05) from 2010 to 2015, followed by a significant annual decrease of 4.8% from 2016 to 2020 (AAPC: -4.8, p < 0.05). The joinpoint regression models identified prominent inflection points around 2009 and 2015, aligning with the years of the ATA's cancer management revisions. These intricate dynamics in thyroid cancer incidence trends from 2000 to 2020 were shaped by SES and histologic, geographic, and racial/ethnic factors. Conclusions: Thyroid cancer incidence trends over the past two decades can be partially explained by the changes in thyroid cancer screening and management recommendations. These findings underscore the importance of cancer management strategies and highlight the need for targeted interventions to address disparities in thyroid cancer incidence across minority demographic groups.

Trends in papillary thyroid cancer mortality in Denmark according to stage and education

OBJECTIVE

Few studies exist on trends in papillary thyroid cancer (PTC) survival and mortality according to stage and level of socioeconomic status.

DESIGN

Nationwide cohort study.

PATIENTS AND MEASUREMENTS

Patients diagnosed with PTC during 2000-2015 in Denmark were identified from the Danish Cancer Registry and followed until the end of 2020. We evaluated 5-year all-cause mortality and relative survival according to stage and 5-year mortality rates with corresponding average annual percentage changes (AAPCs) according to stage and education. Finally, we assessed the association between several factors and mortality of PTC using Cox regression.

RESULTS

For the 2006 cases of PTC diagnosed during 2000-2015, relative survival tended to increase and mortality rates tended to decrease for all stages. For localized PTC, mortality rates tended to decrease among individuals with medium education (AAPC = -7.0, 95% confidence interval [CI]: -14.7 to 1.5), but showed an increasing pattern among individuals with long education (AAPC = 19.8, 95% CI: -4.2 to 50.0). For nonlocalized PTC, mortality rates showed a decreasing tendency among individuals with medium and long education (AAPC = -5.5, 95% CI: -13.2 to 2.9, and AAPC = -10.4, 95% CI: -20.8 to 1.4, respectively). Being diagnosed with PTC in a more recent calendar period and long education were associated with a lower mortality rate in the Cox regression analysis.

CONCLUSIONS

A pattern of an increasing relative survival and decreasing mortality rates of PTC across all stages was seen in Denmark during 2000-2015. The decreasing pattern in mortality rates was most evident in individuals with localized stage and medium education, and in individuals with nonlocalized stage and medium or long education.

Association between educational attainment and thyroid cancer: evidence from a univariable and multivariable Mendelian randomization study

BACKGROUND

Thyroid cancer and educational attainment have been related in observational studies. It is unclear if these correlations indicate causative relationships.

METHODS

Using large-scale genome-wide association studies (GWAS) datasets, we conducted an univariable and multivariable Mendelian randomization (MR) study to assess a potential connection between educational attainment and thyroid cancer. The inverse-variance weighted (IVW) analysis method is used as our primary outcome. Additionally, we carry out several sensitivity analyses to evaluate the pleiotropy and robustness of the causal estimates.

RESULTS

Univariate MR study shows 4.2 years of additional education is associated with a 41.4% reduction in thyroid cancer risk (OR = 0.586; 95% CI: 0.378-0.909; P = 0.017). Further multivariable MR analysis revealed that body mass index (BMI) acted as a partial mediating factor in the protective impact of higher educational attainment against thyroid cancer.

CONCLUSION

This MR study provided genetic evidence that longer education attainment is related to a lower risk of thyroid cancer. Strategies of expanding education may reduce the burden of thyroid cancer in the world.