Radioiodine Therapy Does Not Change the Atherosclerotic Burden of the Carotid Arteries

Cardiovascular Effects of Cumulative Doses of Radioiodine in Differentiated Thyroid Cancer Patients with Type 2 Diabetes Mellitus

Radioiodine (131I) therapy for differentiated thyroid cancer (DTC) involves exposure of the whole body, including the heart, to ionizing radiation. This exposure to the subsequent risk of heart disease is uncertain, especially in patients with DTC associated with type 2 diabetes mellitus (DTC/+T2DM). The current study aimed to assess the relationship between left ventricular ejection fraction (LVEF), high cumulative 131I dose, and peripheral blood parameters in patients with DTC/−T2DM and DTC/+T2DM. The study enrolled 72 female patients with DTC/−T2DM and 24 with DTC/+T2DM who received cumulative 131I doses above 150 mCi (5.55 GBq). LVEF was lower in patients with concomitant T2DM than those without (p < 0.001). The cumulative 131I dosage was inversely correlated with LVEF only in DTC/−T2DM patients (r = −0.57, p < 0.001). In the DTC/+T2DM group, LVEF was negatively associated with absolute platelet count (r = −0.67, p < 0.001) and platelet-to-lymphocyte ratio (r = −0.76, p < 0.001). Our results demonstrate that exposure to high cumulative 131I doses has different cardiovascular effects in DTC/−T2DM and DTC/+T2DM.

Radioactive Iodine Treatment and the Risk of Long-Term Cardiovascular Morbidity and Mortality in Thyroid Cancer Patients: A Nationwide Cohort Study

(1) Background: This study aimed to investigate the association between radioactive iodine (RAI) and long-term cardiovascular disease (CVD) morbidity/mortality in thyroid cancer. (2) Methods: The study was conducted using data from the Taiwan National Health Insurance Database during 2000–2015. Thyroid cancer patients aged ≥20 years were categorized into RAI (thyroidectomy with RAI) and non-RAI (thyroidectomy only) groups. The Cox proportional hazard regression model and Kaplan–Meier method were used for analysis. (3) Results: A total of 13,310 patients were included. Kaplan–Meier analysis demonstrated that the two groups had similar cumulative risks of CVD (log-rank p = 0.72) and CVD-specific mortality (log-rank p = 0.62). On Cox regression analysis of different RAI doses, the risk of CVD was higher in the cumulative dosage >3.7 GBq (hazard ratio = 1.69, 95% confidence interval = 1.24–2.40, p < 0.001). (4) Conclusions: RAI was not associated with an increased risk of CVD in thyroid cancer. However, CVD surveillance is indicated in the patients receiving the cumulative RAI dosage above 3.7 GBq.

Cause-specific mortality after diagnosis of thyroid cancer: a large population-based study

PURPOSE

The study aimed to disclose mortality pattern and quantitatively evaluate risks for cause-specific mortality among thyroid cancer survivors.

METHODS

We included 173,710 patients from the Surveillance, Epidemiology, and End Results (SEER) database with thyroid cancer diagnosed between 1975 and 2015. Standardized mortality ratio (SMR) was calculated using general US population as the reference. Cumulative incidence function curves were constructed to elaborate crude cause-specific mortality by histology. Cox proportional hazards regression model was adopted to identify predictors for cause-specific mortality, expressed as hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

After a median follow-up of 101 months, 23,040 (13.3%) deaths occurred, of which 29.1% and 21.7% were attributable to thyroid cancer and cardiovascular disease (CVD), respectively. CVD SMRs were 1.14, 1.47, 1.21, and 5.66 in patients with follicular, Hürthle cell, medullary and anaplastic histology, respectively. The adjusted HRs of thyroid cancer-specific mortality were 1.59 (95% CI: 1.46-1.74), 1.87 (95% CI: 1.65-2.12), 3.66 (95% CI: 3.31-4.05), and 12.65 (95% CI: 11.50-13.92) for follicular, Hürthle cell, medullary, and anaplastic histology, respectively, as compared with papillary histology; HRs of CVD-specific mortality were 1.23 (95% CI: 1.12-1.34), 1.27 (95% CI: 1.11-1.46), 1.13 (95% CI: 0.96-1.33), and 1.60 (95% CI: 1.19-2.16), respectively. Older age, male sex, nonwhite race, unmarried status, and advanced stage were independent predictors of CVD-specific mortality, while receiving surgery and radiotherapy were protective against CVD-specific mortality.

CONCLUSIONS

We disclosed distinct mortality patterns by histology and identified predictors of CVD-specific mortality in thyroid cancer survivors, supporting CVD intervention for aggressive thyroid cancer.

Effects of radioactive iodine treatment on cardiovascular disease in thyroid cancer patients: a nationwide cohort study

Background

Radioactive iodine (RAI) treatment is a standard treatment in differentiated thyroid cancer (TC). However, its adverse effects on cardiovascular diseases (CVDs) have not been clearly elucidated.

Methods

In this retrospective cohort study based on the Korean National Health Insurance Service-National Health Screening Cohort (2002–2015), we analyzed 4,845 patients with TC with a median follow-up of 66 months. We evaluated and compared the risk of CVD between patients treated with and without RAI therapy. The primary CVD outcome was defined as a composite of ischemic stroke (IS), ischemic heart disease (IHD), hemorrhagic stroke (HS), or heart failure (HF).

Results

Overall, 2,533 patients (52.3%) received RAI treatment with a median cumulative dosage of 103 mCi [interquartile range (IQR), 40–162 mCi]. The incidence of the primary CVD outcome in patients who did not receive RAI therapy and those who did was 17.32 [95% confidence interval (CI), 15.07–19.90] and 13.96 (95% CI, 12.17–16.01) per 1,000 person-years, respectively, indicating an adjusted hazard ratio (HR) of 0.87 (95% CI, 0.71–1.07) after multivariate adjustments for variable confounding factors. The risks of IS (HR, 0.83; 95% CI, 0.51–1.34), IHD (HR, 0.90; 95% CI, 0.71–1.13), HS (HR 1.01; 95% CI, 0.49–2.09), and HF (HR 0.89; 95% CI, 0.49–1.63) were comparable between the patients who received RAI therapy and those who did not. There was no cumulative dose-dependent risk for CVD in TC patients who received RAI treatment.

Conclusions

RAI treatment is a prevalent and crucial treatment for TC, and has been used in more than half of TC patients in Korea from 2004 to 2015. This study found no significant between-group difference for the CVD risk in patients with TC who received RAI treatment and those who did not, giving further evidence to allay concerns related to the adverse effects of RAI.

Long-term cardiovascular and cerebrovascular morbidity in Israeli thyroid cancer survivors

OBJECTIVE

Thyroid cancer (TC) survivors may be at risk of subsequent cardiovascular and cerebrovascular (CaV&CeV) morbidity. The 2009 American Thyroid Association (ATA) guidelines recommended less aggressive treatment for low-risk TC patients. The aim of this study was to assess the atherosclerotic CaV&CeV outcome of Israeli TC survivors compared to individuals with no thyroid disease, and the atherosclerotic CaV&CeV outcome before (2000-2008) and after (2009-2011) implementation of the 2009 ATA guidelines.

METHODS

All members of the largest Israeli healthcare organization who were diagnosed with TC from 1/2000 to 12/2014 (study group) and age- and sex-matched members with no thyroid disease (controls) were included. Adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated using Cox proportional hazards models.

RESULTS

The mean follow-up was 7.6 ± 4.2 and 7.8 ± 4.1 years for the study (n = 5,677, 79% women) and control (n = 23,962) groups, respectively. The former had an increased risk of new atherosclerotic CaV&CeV events (adjusted HR 1.26, 95% CI 1.15-1.39). The 5-year incidence of CaV&CeV was lower (adjusted HR 0.49, 95% CI 0.38-0.62) from 2009 to 2011 compared to 2000 to 2008, but remained higher in the study group than in the control group (adjusted HR 1.5, 95% CI 1.14-1.69).

CONCLUSIONS

This large Israeli population-based cohort study showed greater atherosclerotic CaV&CeV morbidity in TC survivors compared to individuals with no thyroid diseases. There was a trend toward a decreased 5-year incidence of atherosclerotic CaV&CeV events among TC survivors following the implementation of the 2009 ATA guidelines, but it remained higher compared to the general population.

Risk Factors for Cardiovascular Disease Among Thyroid Cancer Survivors: Findings From the Utah Cancer Survivors Study

CONTEXT

Thyroid cancer survivors are at high risk of developing multiple cardiac and vascular conditions as consequence of cancer diagnosis and treatment. However, it is still unclear how the baseline and prognostic factors, as well as cancer treatments, play a role in increasing cardiac and vascular disease risk among thyroid cancer survivors.

OBJECTIVE

To investigate the association between potential risk factors, treatment effects, and cardiovascular disease (CVD) outcomes in thyroid cancer survivors.

DESIGN, SETTING, PATIENTS

Primary thyroid cancer survivors, diagnosed from 1997 to 2012 (n = 3822), were identified using the statewide Utah Population Database. The medical records were used to ascertain information on risk factors and CVD outcomes. Cox proportional hazards models were used to assess the risk of CVD with baseline demographic data and clinical factors.

RESULTS

Among thyroid cancer survivors, age and year at cancer diagnosis, cancer stage, sex, baseline body mass index, baseline comorbidities, and TSH suppression therapy were significantly associated with CVD risk 1 to 5 years after cancer diagnosis. Patients who were male, overweight or obese, older at cancer diagnosis, and diagnosed with cancer since 2005 had an increased risk of CVD compared with patients who were female, had a normal body mass index, were younger at cancer diagnosis, and diagnosed with cancer from 1997 to 1999. Administration of TSH suppression therapy, distant metastases at cancer diagnosis, and a higher Charlson comorbidity index score were associated with an increased CVD risk among thyroid cancer survivors.

CONCLUSIONS

Our findings suggest that examining the effect of thyroid cancer diagnosis, cancer treatment, and demographic characteristics on the risk of CVD is critical.

Association between radioiodine treatment for thyroid cancer and risk of stroke

BACKGROUND

The purpose of this study was to evaluate the association between radioiodine (I-131) therapy for thyroid cancer and the risk of stroke in Taiwan.

METHODS

A total of 10 104 of the patients aged 20 years or older, who were newly diagnosed with thyroid cancer during 2000-2010, were recruited and classified into 2 cohorts according to whether they received I-131 therapy through 1:1 propensity score matching. The cumulative Kaplan-Meier curves for the incidence of stroke in the 2 cohorts were compared using the log-rank test.

RESULTS

After adjustment for age, sex, and comorbidities, the I-131 therapy group showed no significantly higher risk of ischemic stroke (adjusted HR [aHR] = 1.05; 95% confidence interval [CI] = 0.82-1.34) or hemorrhagic stroke (aHR = 1.06; 95% CI = 0.58-1.93) than did the non-I-131 therapy group.

CONCLUSION

The I-131 treatment for thyroid cancer did not increase the risk of stroke during 10-year follow-up.