Thyrotropin suppressive therapy in thyroid carcinoma: what are the targets?

The Effect of Thyrotropin Suppression on Survival Outcomes in Patients with Differentiated Thyroid Cancer: A Systematic Review and Meta-Analysis

Background: Long-term management of intermediate- and high-risk differentiated thyroid cancer (DTC) involves thyrotropin (TSH) suppression with thyroid hormone to prevent potential stimulation of TSH receptors on DTC cells, leading to tumor growth. However, the current guidelines recommending TSH suppression are based on low- to moderate-quality evidence. Methods: We performed a systematic review and meta-analysis of studies evaluating the role of TSH suppression in intermediate- and high-risk DTC patients (≥18 years) treated as per regional guideline-based therapy with a follow-up duration of 5 years (PROSPERO #252396). TSH suppression was defined as "below normal reference range" or, when known, <0.5 mIU/L. Primary outcome measures included (i) composite of progression-free survival (PFS), disease-free survival (DFS), and relapse-free survival (RLFS), and (ii) composite of disease-specific survival (DSS), and overall survival (OS). Secondary outcome included a composite of cardiac or skeletal adverse events. All outcomes and comparisons were represented as TSH suppression versus TSH nonsuppression. Randomized controlled trials, cohort studies, and case-control studies were included for analysis. Pooled hazard ratio (HR) and 95% confidence interval (CI) were calculated using random-effects model. Results: Abstract screening was performed on 6,369 studies. After the exclusion of irrelevant studies and full-text screening, nine studies were selected for the final meta-analysis. Based on seven studies (3,591 patients), the composite outcome of PFS, DFS, and RLFS was not significantly different between TSH suppression and nonsuppression groups (HR: 0.75; 95% CI: 0.48-1.17; I2 = 76%). Similarly, a DSS and OS composite outcome assessment based on four studies (3,616 patients) did not favor TSH suppression (HR: 0.69; 95% CI: 0.31-1.52; I2 = 88%). Even after excluding studies of lower quality, the primary outcomes were not significantly different between the TSH suppression and nonsuppression cohorts. The secondary outcome, obtained from two studies (1,294 patients), was significantly higher in the TSH-suppressed groups (HR: 1.82; 95% CI: 1.30-2.55; I2 = 0%). Significant study heterogeneity was noted for primary outcomes. Conclusion: TSH suppression in intermediate- and high-risk DTC may not improve survival outcomes but may increase the risk of secondary complications. However, the limited evidence and study heterogeneity warrant cautious interpretation of our findings. Registration: PROSPERO #252396.

Cardiovascular Outcomes of Differentiated Thyroid Cancer Patients on Long Term TSH Suppression: A Systematic Review and Meta-Analysis

We performed a systematic review and meta-analysis of the literature regarding cardiovascular outcomes of differentiated thyroid cancer (DTC) patients who are on long term thyroid stimulating hormone suppression. Searches were carried out using Prisma guidelines in Medline, Embase, CENTRAL, CINAHL and Scopus databases. Eligible papers were those which investigated discrete cardiovascular clinical outcomes in TSH suppressed patients and meta-analysis of selected studies was performed using Revman 5.4.1. We found a total of 195 879 DTC patients with median length to follow up of 8.6 years (range 5-18.8 years). Analysis showed DTC patients to be at higher risk of atrial fibrillation (HR 1.58, 95% CI 1.40, 1.77), stroke (HR 1.14, 95% CI 1.09, 1.20) and all-cause mortality (HR 2.04, 95% CI 1.02, 4.07). However, there was no difference in risk of heart failure, ischemic heart disease or cardiovascular mortality. These findings suggest that degree of TSH suppression must be titrated to accommodate risk of cancer recurrence and cardiovascular morbidity.

A comparative analysis of treatment efficacy in intermediate-risk thyroid cancer

PURPOSE

This study aimed to evaluate the efficacy of different treatment combinations on patient survival in intermediate-risk differentiated thyroid cancer (DTC).

METHODS

The 2004-2017 National Cancer Database was queried for intermediate-risk papillary (PTC), follicular (FTC), or Hurthle cell (HTC) thyroid cancer patients. Four treatments were analyzed using Kaplan Meier and multivariable Cox regression: surgery, surgery with adjuvant radioiodine ablation (S + RAI), surgery with adjuvant thyroid-stimulating hormone suppression therapy (S + THST), and S + RAI + THST. Kaplan-Meier and multivariable Cox proportional-hazards analyses evaluated treatment-associated overall survival (OS).

RESULTS

Of 65,736 patients, 72.2% were female and the average age was 45.4 ± 15.4 years. The 10-year OS rates for PTC, FTC, and HTC were 93.2%, 85.2%, and 78.5%, respectively. S + RAI + THST exhibited higher OS than surgery alone and S + RAI (all p < 0.05). Compared to surgery alone, S + RAI + THST demonstrated reduced mortality in PTC (Hazard Ratio [HR]: 0.628, p < 0.001), FTC (HR: 0.490, p < 0.001), and HTC (HR: 0.520, p = 0.006). Similarly, adjuvant RAI + THST reduced mortality regardless of lymphovascular invasion (HR: 0.490, p < 0.001), N1a (HR: 0.570, p < 0.001) or N1b metastasis (HR: 0.621, p < 0.001), or positive margin status (HR: 0.572, p < 0.001).

CONCLUSIONS

Treatment combinations demonstrated varying efficacies in intermediate-risk DTC depending on histology and tumor characteristics, with S + RAI + THST exhibiting the greatest treatment response.

Progressive diastolic dysfunction in survivors of pediatric differentiated thyroid carcinoma

BACKGROUND

Pediatric differentiated thyroid cancer (DTC) has an excellent prognosis but unknown late effects of treatment. The initial cardiac evaluation showed subclinical diastolic dysfunction in 20% of adult survivors. The objective of this follow-up study was to determine the clinical course of this finding.

METHODS

This multicenter study, conducted between 2018 and 2020, re-evaluated survivors after 5 years. The primary endpoint was echocardiographic diastolic cardiac function (depicted by the mean of the early diastolic septal and early diastolic lateral tissue velocity (e' mean)). Secondary endpoints were other echocardiographic parameters and plasma biomarkers.

RESULTS

Follow-up evaluation was completed in 47 (71.2%) of 66 survivors who had completed their initial evaluation. Of these 47 survivors, 87.2% were women. The median age was 39.8 years (range: 18.8-60.3), and the median follow-up after the initial diagnosis was 23.4 years (range: 10.2-48.8). Between the first and second evaluation, the e' mean significantly decreased by 2.1 cm/s (s.d. 2.3 cm/s, P < 0.001). The median left ventricular ejection fraction did not significantly change (58.0% vs 59.0%, P= NS). In the best explanatory model of e' mean, multivariate linear regression analysis showed that BMI and age were significantly associated with e' mean (β coefficient: -0.169, 95% CI: -0.292; -0.047, P = 0.008 and β coefficient: -0.177, 95% CI: -0.240; -0.113, P < 0.001, respectively).

CONCLUSIONS AND RELEVANCE

In these relatively young survivors of pediatric DTC, diastolic function decreased significantly during 5-year follow-up and is possibly more pronounced than in normal aging. This finding requires further follow-up to assess clinical consequences.

Bone-density testing interval and transition to osteoporosis in differentiated thyroid carcinoma patients on TSH suppression therapy

OBJECTIVE

Thyrotropin (TSH) suppression therapy is a standard treatment after surgery for differentiated thyroid carcinoma (DTC). It may be associated with osteoporosis in postmenopausal women. However, there are no guidelines for bone mineral density (BMD) testing intervals to screen for osteoporosis in these patients. Therefore, we evaluated the timing of repeated BMD testing in DTC patients with TSH suppression according to baseline T-scores.

DESIGN, PATIENTS, AND MEASUREMENT

We retrospectively evaluated 658 DTC patients who underwent BMD testing more than twice between January 2007 and January 2020. A 1:3 propensity score matching was conducted to compare the timing of repeated BMD tests between the DTC and non-DTC groups. We stratified the participants into four groups based on their baseline T-scores: normal (-1.00 or higher), mild osteopenia (-1.01 to -1.49), moderate osteopenia (-1.50 to -1.99), and severe osteopenia (-2.00 to -2.49). Additionally, the 10% of patients in each group that transitioned to osteoporosis were analysed.

RESULTS

The estimated BMD testing interval for 10% of patients who developed osteoporosis was 85 months for patients with initially mild osteopenia, 65 months for those with moderate osteopenia, and 15 months for those with severe osteopenia in the DTC group. In the non-DTC group, the testing intervals for mild, moderate, and severe osteopenia were 98, 57, and 13 months, respectively. On multivariate analysis, baseline T-score (mild osteopenia: hazard ratio [HR] 5.91, p = .105; moderate osteopenia: HR, 25.27, p = .02; and severe osteopenia: HR, 134.82, p < .001) and duration of TSH suppression (tertile 2: HR, 2.25, p = .005; Tertile 3: 1.78, p = .033) were independent risk factors for osteoporosis in the DTC group.

CONCLUSION

This study provides guidance for the timing of repeated BMD tests in women over 50 years of age with TSH suppression. The rescreening interval for BMD testing can be modified based on the baseline T-score. The appropriate BMD testing intervals in female DTC patients were similar to those in non-DTC females.

99Tc-Methylene Diphosphonate Treatment is Safe and Efficacious for Osteoporosis in Postmenopausal Differentiated Thyroid Cancer Patients Undergoing TSH Suppression: A Three-Center Non-Randomized Clinical Study

Objective

To investigate the effects of ⁹⁹Tc-methylene diphosphonate (⁹⁹Tc-MDP) on osteoporosis (OS) in postmenopausal patients with differentiated thyroid cancer (DTC) under thyroid stimulating hormone (TSH) suppression.

Patients and Methods

Patients (n = 142) were divided into two groups: (1) ⁹⁹Tc-MDP (n = 70) and (2) alendronate (n = 72) treatments (NCT 02304757). Bone mineral density (BMD) in the lumbar spine and hip was evaluated by DXA, along with bone turnover markers, safety, and quality of life (QOL) using SF-36 at three time points: before treatment and at 6 and/or 12 months after treatment.

Results

The percentage change of BMD in total lumbar spine or hip showed no significant difference throughout the study (P > 0.025). ⁹⁹Tc-MDP and alendronate treatment alone significantly increased BMD in the lumbar spine, but alendronate treatment also significantly increased BMD in total hip at 6 and 12 months, as compared with the baseline. There were no significant differences in the results of the SF-36 scores between the two treatment groups at any time during the whole study period. ⁹⁹Tc-MDP significantly increased bone formation markers of osteocalcin at 6 and 12 months (P all < 0.05), PINP at 12 months (P = 0.001), and bone resorption markers of β-CTX at 6 and 12 months (p < 0.05) as compared with the alendronate treated group. No adverse event was observed in the ⁹⁹Tc-MDP treatment group compared with alendronate (P = 0.014).

Conclusion

⁹⁹Tc-MDP was as efficacious as alendronate in the improvement of lumbar BMD for DTC patients with OS under TSH stimulation. ⁹⁹Tc-MDP was shown to be safe and improved patients’ QOL.

Incident atrial fibrillation in patients with differentiated thyroid cancer: a meta-analysis

Differentiated thyroid cancer (DTC) represents the most common form of thyroid neoplasms and is becoming increasingly prevalent. Evidence suggests a possible relationship between DTC diagnosis and subsequent atrial fibrillation (AF). If confirmed, this may present an alarming health risk (AF) in an otherwise condition with a relatively good prognosis (DTC). The aim of this systematic review and meta-analysis is to provide for the first time a pooled estimate of AF incidence in DTC patients in comparison to healthy controls. A detailed search in electronic databases, clinical trial registries and grey literature was performed to identify studies reporting the incidence of AF in DTC patients. Newcastle-Ottawa quality assessment scale was used to assess study quality. We used a random effects (RE) generalized linear mixed model (GLMM) in pooling of individual studies and also calculated a prediction interval for the estimate of a new study. Six observational studies met the eligibility criteria, which included totally 187,754 patients with DTC and 199,770 healthy controls. The median follow-up period was 4.3 to 18.8 years; the incidence rate of AF was 4.86 (95% CI, 3.29 to 7.17, I2 = 96%) cases per 1000 person-years, while the incidence rate ratio was 1.54 (95% CI, 1.44 to 1.65, I2 = 0%, 95% PI, 1.33 to 1.78).This is the first meta-analysis to confirm that patients with DTC are at a high risk for developing AF, which may be attributed to a state of iatrogenic hyperthyroidism due to long-term thyrotropin suppression therapy.

Anaplastic thyroid cancer: How far can we go?

Globally, thyroid cancer accounts for 2 % of all cancer diagnoses, and can be classified as well-differentiated or undifferentiated. Currently, differentiated thyroid carcinomas have good prognoses, and can be treated with a combination of therapies, including surgical thyroidectomy, radioactive iodine therapy and hormone-based therapy. On the other hand, anaplastic thyroid carcinoma, a subtype of undifferentiated thyroid carcinoma characterized by the loss of thyroid-like phenotype and function, does not respond to either radioactive iodine or hormone therapies. In most cases, anaplastic thyroid carcinomas are diagnosed in later stages of the disease, deeming them inoperable, and showing poor response rates to systemic chemotherapy. Recently, treatment courses using multiple-target agents are being explored and clinical trials have shown very promising results, such as overall survival rates, progression-free survival and tumor shrinkage. This review is focused on thyroid carcinomas, with particular focus on anaplastic thyroid carcinoma, exploring its undifferentiated nature. Special interest will be given to the treatment approaches currently available and respective obstacles or drawbacks. Our purpose is to contribute to understand why this malignancy presents low responsiveness to current treatments, while overviewing novel therapies and clinical trials.

Oncological impact of hypothyroidism and levothyroxine supplementation following hemithyroidectomy in patients with papillary thyroid carcinoma

BACKGROUND

We aimed to evaluate the oncological impact of hypothyroidism and levothyroxine (LT) supplementation after hemithyroidectomy in patients with papillary thyroid carcinoma (PTC).

METHODS

We retrospectively examined 401 patients who underwent hemithyroidectomy for classic PTC and who were postoperatively followed-up with ≥3 thyroid function measurements for ≥24 months.

RESULTS

During 77.4 months of follow-up, 268/401 patients (66.8%) developed hypothyroidism and 19/401 patients (4.7%) showed recurrence. Recurrence rates did not differ between the euthyroidism and hypothyroidism development groups. Recurrence rates were significantly lower in the LT group than in the no-LT group, although mean postoperative thyroid-stimulating hormone (TSH) levels were not different between the two groups. Univariate and multivariate analysis showed that tumors sized >1 cm and lack of LT supplementation were significantly associated with recurrence.

CONCLUSIONS

Postoperative hypothyroidism development was not a risk factor for PTC recurrence after hemithyroidectomy. Nevertheless, LT supplementation reduced recurrence risk without suppressing TSH.

Levothyroxine Supplementation Following Hemithyroidectomy: Incidence, Risk Factors, and Characteristics

BACKGROUND

The goal of the present study was to determine the actual incidence, predictive risk factors, and clinical characteristics of levothyroxine supplementation (LT4S) used for the management of hypothyroidism after hemithyroidectomy.

METHODS

From 2008 to 2015, we included 535 patients who underwent hemithyroidectomy. LT4S was initiated based on three major criteria: the development of overt hypothyroidism, subclinical hypothyroidism with thyroid-stimulating hormone (TSH) levels > 10 mIU/L, or subclinical hypothyroidism with TSH levels of 4.5-10 mIU/L with associated signs/symptoms.

RESULTS

During the 69-month follow-up period, 321 patients (60%) developed overall hypothyroidism following hemithyroidectomy, and 141 ultimately required LT4S, with an overall LT4S incidence of 26.4%. The most common cause of LT4S initiation was subclinical hypothyroidism with TSH levels > 10 mIU/L. In 141 patients with LT4S, the mean maintenance dose of levothyroxine was 1.34 μg/kg, and only 6 patients (4.3%) discontinued LT4S during the follow-up. The 1-, 3-, 5-, and 7-year LT4S-free survival rates of 535 patients were 88.6%, 80.2%, 73.8%, and 69.1%, respectively. Preoperative TSH levels > 2.12 mIU/L and coexistence of Hashimoto's thyroiditis were significantly associated with LT4S following hemithyroidectomy. The risk of LT4S increased by 1.401 times, as preoperative TSH levels increased by 1 mIU/L.

DISCUSSION

A quarter of patients required LT4S after hemithyroidectomy for the management of hypothyroidism, with a mean maintenance levothyroxine dose of 1.34 μg/kg. The preoperative TSH level and coexistence of Hashimoto's thyroiditis were significant predictive factors of LT4S following hemithyroidectomy.

Risk of incident circulatory disease in patients treated for differentiated thyroid carcinoma with no history of cardiovascular disease

CONTEXT

The incidence of differentiated thyroid cancer (DTC) is increasing, yet the prognosis is favourable and long-term survival is expected. Exogenous TSH suppression has been used for many years to prevent DTC recurrence and may be associated with increased risks of circulatory diseases.

DESIGN

Risks of circulatory disease in patients treated for DTC were compared to randomly matched patients without DTC (controls) up to a 1:5 ratio using age, sex, body mass index (BMI) and smoking as the matching parameters in a population-based, open cohort study using The Health Improvement Network.

PATIENTS

A total of 3009 patients treated for DTC with no pre-existing cardiovascular disease were identified and matched to 11 303 controls, followed up to median of 5 years.

RESULTS

A total of 1259 incident circulatory events were recorded during the observation period. No difference in the risk of ischaemic heart disease (IHD) (adjusted hazards ratio [aHR]: 1.04, 95% CI: 0.80-1.36) or heart failure (HF) (aHR: 1.27, 95% CI: 0.89-1.81) was detected. The risk of atrial fibrillation (AF) and stroke was significantly higher in patients with DTC (aHR: 1.71, 95% CI: 1.36-2.15 and aHR: 1.34, 95% CI: 1.05-1.72, respectively). In a sensitivity analysis limited to newly diagnosed patients with DTC, only the risk of AF was consistently elevated (aHR: 1.86, 95% CI: 1.33-2.60).

CONCLUSIONS

The increased risk of AF in patients who have undergone treatment for DTC but without pre-existing CVD may warrant periodic screening for this arrhythmia. Whereas no evidence of increased risk of IHD or HF was observed, the increased risk of stroke/TIA warrants further investigation.

Postoperative Thyroid-Stimulating Hormone Levels Did Not Affect Recurrence after Thyroid Lobectomy in Patients with Papillary Thyroid Cancer

BACKGROUND

Thyroid-stimulating hormone (TSH) suppression is recommended for patients who undergo thyroidectomy for differentiated thyroid cancer (DTC). However, the impact of TSH suppression on clinical outcomes in low-risk DTC remains uncertain. Therefore, we investigated the effects of postoperative TSH levels on recurrence in patients with low-risk DTC after thyroid lobectomy.

METHODS

Patients (n=1,528) who underwent thyroid lobectomy for papillary thyroid carcinoma between 2000 and 2012 were included in this study. According to the mean and dominant TSH values during the entire follow-up period or 5 years, patients were divided into four groups (<0.5, 0.5 to 1.9, 2.0 to 4.4, and ≥4.5 mIU/L). Recurrence-free survival was compared among the groups.

RESULTS

During the 5.6 years of follow-up, 21 patients (1.4%) experienced recurrence. Mean TSH levels were within the recommended low-normal range (0.5 to 1.9 mIU/L) during the total follow-up period or 5 years in 38.1% or 36.0% of patients. The mean and dominant TSH values did not affect recurrence-free survival. Adjustment for other risk factors did not alter the results.

CONCLUSION

Serum TSH levels did not affect short-term recurrence in patients with low-risk DTC after thyroid lobectomy. TSH suppression should be conducted more selectively.

Management of Papillary Thyroid Microcarcinoma

The worldwide incidence of thyroid cancer is increasing. A third of new thyroid cancer cases are papillary thyroid microcarcinoma (PTM), which are 1 cm or less. These tumors are mostly indolent with excellent prognosis. Although thyroid surgery is the most common management option for patients with PTM, new management options demand that treatment decisions must be individualized and based on patient's preference, context, and biology. This article describes management options for PTM patients and shared decision-making as a novel method for individualizing care.

Surgical options for thyroid cancer and post-surgical management

INTRODUCTION

Differentiated thyroid cancer (DTC), which includes papillary and follicular, is the most common type of thyroid cancer and the incidence is rising. Survival rates of DTC are excellent, so the focus of management should be to optimize the initial oncological surgical resection, while providing follow up and adjunct therapies to improve long-term outcomes.

AREAS COVERED

It is important for providers to be aware of the most recent guidelines for DTC management, as practices have changed in recent years. In this review, we will highlight some of the updates in the American Thyroid Association (ATA) guidelines and the American Joint Committee on Cancer (AJCC) edition changes in order to better guide practitioners in the management of the evolving treatment strategies. Management of DTC includes diagnosis of thyroid nodules, defining the best operative or non-operative treatment for patients using a multidisciplinary approach, and surveillance of DTC to optimize patients in terms of both clinical and quality of life outcomes.

EXPERT COMMENTARY

As the rate of DTC rises yet the mortality remains stable, management focuses on disease-free follow up and optimal long-term outcomes. Current controversies in management of DTC include proper oncological surgery depending on the nature and size of the DTC, the cytopathology nomenclature, management of lymph node disease, and appropriate surveillance strategies. Preoperative risk stratification is key. We have many modalities to aid in that stratification, such as identifying known concerning features of nodules with expert-performed ultrasound, thyroglobulin (Tg) levels, molecular testing, and evidence based outcomes data for recurrence rates. However, many individual cases still present with multiple management options, thus highlighting the importance of patient discussion and a multidisciplinary approach. It is important for providers to recognize that the short and long-term follow up must be guided by surveillance studies, and patients need to be re-risk stratified in order to optimize detection of recurrence yet sustain quality of life.

Reduced insulin sensitivity in differentiated thyroid cancer patients with suppressed TSH

OBJECTIVE

TSH-suppression is a therapy for thyroid cancer management, but it may lead to adverse effects, which should be balanced with its benefits. Previous studies evaluating the consequences of TSH suppression on insulin sensitivity have only been done with indirect techniques, and results were controversial. Therefore, we aimed to assess insulin sensitivity in patients with thyroid cancer and suppressed thyroid-stimulating hormone (TSH) with the most appropriate direct method (hyperinsulinemic-euglycemic clamp) in order to get a more conclusive response about the topic.

METHODS

A group of 20 non-obese and non-diabetic thyroid cancer patients with suppressed TSH underwent a hyperinsulinemic-euglycemic clamp to evaluate insulin sensitivity. Their results were compared to the results of a sex and body mass index (BMI) -paired control group composed of 20 healthy volunteers.

RESULTS

Patients were all female, aged 36.8 ± 10.2 years-old, with mean TSH 0.1 ± 0.1 μIU/mL and mean BMI 26.2 ± 3.3 kg/m². Insulin sensitivity, determined by the insulin-stimulated glucose uptake (M-value), was lower in the patients group (4.2 ± 1.6 mg/min*kg versus 5.8 ± 1.7, age-adjusted p-value = 0.0205).

CONCLUSION

This study shows for the first time that subclinical thyrotoxicosis in patients with thyroid cancer is associated with insulin resistance, as measured by hyperinsulinemic-euglycemic clamp technique. Such finding may be taken into consideration by clinicians when balancing risks and benefits of TSH-suppression therapy in thyroid cancer patients.

An overall and dose-response meta-analysis for thyrotropin and thyroid cancer risk by histological type

Thyrotropin (TSH) is thought as a risk factor for thyroid cancer. However, the effect of serum TSH might depend on histological types of thyroid cancer. We searched for related studies including serum TSH as an exposure and thyroid cancer as a result in PUBMED, EMBASE and Chinese National Knowledge Infrastructure up to April 21, 2016. This meta-analysis included 22 articles with 53,538 participants. When comparing all histological thyroid cancer, the pooled odds ratios of thyroid cancer in patients with nodules was found to increase significantly with higher serum TSH concentrations for differentiated thyroid carcinoma (1.88 vs .1.48, P = 0.0000) and papillary thyroid carcinoma (2.08 vs. 1.48, P = 0.0006). Each 1 mU/L increase of serum TSH was associated with 14% greater risk of thyroid cancer for all histological thyroid cancer, 16% for differentiated thyroid carcinoma and 22% for papillary thyroid carcinoma. In addition, high serum TSH was associated with a reduced risk for follicular thyroid carcinoma (OR = 0.73, 95% CI: 0.52, 1.02). This meta-analysis suggested high serum TSH concentration is risky for papillary thyroid carcinoma but not for follicular thyroid carcinoma.

High Prevalence of Radiological Vertebral Fractures in Women on Thyroid-Stimulating Hormone-Suppressive Therapy for Thyroid Carcinoma

CONTEXT

Bone loss and nonvertebral fractures have been reported in patients with differentiated thyroid carcinoma (DTC) undergoing thyroid-stimulating hormone (TSH) suppressive therapy. Radiological vertebral fractures (VFs) are an early and clinically crucial marker of bone fragility.

OBJECTIVE AND DESIGN

A cross-sectional study to evaluate the prevalence and determinants of radiological VFs in women receiving l-thyroxine (L-T4) therapy for DTC.

PATIENTS AND INTERVENTIONS

A total of 179 consecutive women (median age, 59 years; n = 178 postmenopausal) who had undergone thyroidectomy for DTC and were currently receiving L-T4 were evaluated for radiological VFs and bone mineral density (BMD). There were three TSH target levels [<0.5 mU/L, group 1 (n = 83); 0.5 to 1.0 mU/L, group 2 (n = 50); >1.0 mU/L, group 3 (n = 46)].

RESULTS

VFs were found in 51 patients (28.5%), with significantly (P < 0.001) higher prevalence in group 1 (44.6%) as compared with group 2 (24.0%) and group 3 (4.3%). VF prevalence was not significantly different among patients in group 1 with normal BMD, osteopenia, or osteoporosis, whereas in groups 2 and 3, VFs were more frequent in patients with osteoporosis than in those with either osteopenia or normal BMD. In the whole population, VFs were significantly and independently associated with TSH level <1.0 mU/L; densitometric diagnosis of osteoporosis at lumbar spine, femoral neck, or total hip; age of patients; and duration of L-T4 therapy.

CONCLUSION

The prevalence of VFs was high in women with DTC who were undergoing long-term, suppressive L-T4 therapy.

The effect of long-term thyroid-stimulating hormone suppressive therapy on the gonadal steroid hormones of patients with thyroid carcinoma after surgery

Background

To analyze the effect of long-term thyroid-stimulating hormone (TSH) suppressive therapy on the gonadal hormones and related symptoms in patients after surgery.

Methods

From 2008 to 2011, totally 238 patients were recruited, who underwent thyroid surgery and subsequent TSH suppression treatment in Department of thyroid Surgery, China-Japan Union hospital, Jilin University. Then their postoperative follow-up data (3-8 years) were collected, including operational method, pathological diagnosis, whether processed radioiodine therapy and the period/dose of TSH suppression treatment. In addition, the menstrual cycle, menstruation quantity, whether accompanied with dysmenorrheal and menstrual disorder or not, date of last menstrual period, ages of menopause and so on were also collected.

Results

(I) Neither the level nor the duration of TSH treatment had any function on estradiol (E2) and testosterone (T) in male patients; (II) in the subgroup of patients with TSH treatment for 3-5 years, patients who took high dose of TSH (TSH ≥0.5 U/L) obtained the lower T level compared with the group of medium dose (1.08±0.34 vs. 1.36±0.46 nmol/L, P=0.001); (III) in the medium dose (0.1 IU/L ≤ TSH <0.5 IU/L) of TSH treatment, patients in luteal phase showed significant difference between two separate durations as the E2 level was 196.0 pmol/L in 3-5 years group vs. 442.5 pmol/L in 6-8 years group, P=0.018; (IV) the level of follicle-stimulating hormone (FSH) did not show any change in terms of the dose and the duration of TSH treatment; (V) the menstrual volume, dysmenorrhea condition, menstrual cycle and menopause related indicators did not show any difference in terms of doses and duration of TSH treatment (P=0.701, 0.412 and 0.507 respectively).

Conclusions

The long term of TSH repressive therapy after surgery did not affect T and E2 level in male patients. As for female patients, the impact was mainly reflected in the T and E2 levels especially in female sexual maturity but not FSH level. In addition, TSH treatment did not play any role on menstruation or menopause.

Reactivity of thyroid papillary carcinoma cells to thyroid stimulating hormone-dominated endocrine therapy

This study investigated the effect of thyroid stimulating hormone (TSH) on the proliferation of papillary thyroid carcinoma (PTC) cells and the therapeutic effect of levothyroxine sodium (TH). PTC cells (TPC-1) were cultured using 0.1, 1.0 and 10 U/l TSH and 10⁻², 10⁻⁴ and 10⁻⁶ mol/l TH. After the appropriate concentration was screened, TPC-1 cells were further divided into control group, TSH group, TH group and TSH+TH group. The cell proliferation was detected via methyl thiazolyl tetrazolium (MTT) method, TPC-1 cell cycle was detected via flow cytometer, and the mRNA and protein expression of cyclin D1 were detected via real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Compared with control group, TSH significantly promoted the proliferation of TPC-1 cells (P<0.05 or P<0.01), obviously promoted the transition of TPC-1 cells from G1 phase to S phase (P<0.01) and remarkably increased the mRNA and protein expression of cyclin D1 (P<0.01); but TH had a significant inhibitory effect on these results of TSH (P<0.05 or P<0.01). TSH can promote the proliferation of PTC cells, and the appropriate complement of TH can inhibit its proliferation.

Histological and ultrastructural alterations of rat thyroid gland after short-term treatment with high doses of thyroid hormones

The aim of the present study was to investigate histological alterations of rat thyroid gland after short-term treatment with supraphysiological doses of thyroid hormones. Rats from experimental groups were treated with triiodothyronine (T3) or thyroxine (T4) during five days. In both treated groups, thyrocyte height was reduced and follicular lumens were distended. Progressive involutive changes of the thyroid parenchyma were apparent, including follicular remodeling (fusion) and death of thyrocytes. Morphological changes confirmed by quantitative analysis were more pronounced in the T4-treated group. Our results demonstrate that thyrotoxicosis, whether induced by T3 or T4, leads to different grades of thyroid tissue injury, including some irreversible damages. These changes might be explained at least in part by lack of trophic and cytoprotective effects of the thyroid stimulating hormone. Since the period required for morphophysiological recovery may be unpredictable, findings presented here should be taken into consideration in cases where the thyroid hormones are used as a treatment for thyroid and non-thyroid related conditions.

PRE-ABLATION THYROGLOBULIN AND THYROGLOBULIN TO THYROID-STIMULATING HORMONE RATIO MAY BE ASSOCIATED WITH PULMONARY METASTASES IN CHILDREN WITH DIFFERENTIATED THYROID CANCER

OBJECTIVE

Pediatric differentiated thyroid cancer (DTC) frequently presents with extensive disease. We studied the value of pre-ablation thyroglobulin (Tg) and Tg normalized to thyroid-stimulating hormone (TSH) levels in predicting distant metastases in pediatric patients with DTC.

METHODS

This is a retrospective cohort study of patients <21 years old who underwent thyroidectomy followed by ¹³¹I ablation for DTC at 3 university hospitals over 20 years. Tg levels and the Tg/TSH ratio following surgery but prior to ¹³¹I ablation were assessed. The presence of distant metastatic disease was determined from the postablation whole-body scan.

RESULTS

We studied 44 patients with a mean age of 15.2 years (range 7 to 21 years) and mean tumor size of 2.8 cm. Eight patients had distant metastases and had a higher mean pre-ablation Tg value compared to patients without distant metastases (1,037 μg/L versus 93.5 μg/L, P<.01). The pre-ablation Tg/TSH ratio was also associated with the presence of distant metastases: 12.5 ± 18.8 μg/mU in patients with distant metastases versus 0.7 ± 1.8 μg/mU in patients without (P<.01). A nomogram to predict distant metastases yielded areas under the receiver operating characteristic curve of 0.85 for Tg and 0.83 for Tg/TSH ratio.

CONCLUSION

After initial thyroidectomy, elevated preablation Tg and Tg/TSH ratio are associated with distant metastatic disease in pediatric DTC. This may inform the decision to ablate with ¹³¹I, as well as the dosage.

ABBREVIATIONS

ATA = American Thyroid Association CI = confidence interval DTC = differentiated thyroid cancer OR = odds ratio ROC = receiver operating characteristic Tg = thyroglobulin.

Thyroid Hormone Replacement in Patients Following Thyroidectomy for Thyroid Cancer

Thyroid hormone replacement therapy in patients following thyroidectomy for thyroid cancer, although a potentially straightforward clinical problem, can present the clinician and patient with a variety of challenges. Most often the problems are related to the dose and preparation of thyroid hormone (TH) to use. Some patients feel less well following thyroidectomy and/or radioiodine ablation than they did before their diagnosis. We present evidence that levothyroxine (L-T4) is the preparation of choice, and keeping the thyroid-stimulating hormone (TSH) between detectable and 0.1 mU/L should be the standard of care in most cases. In unusual circumstances, when the patient remains clinically hypothyroid despite a suppressed TSH, we acknowledge there may be as yet unidentified factors influencing the body's response to TH, and individualized therapy may be necessary in such patients.

A Clinical Framework to Facilitate Risk Stratification When Considering an Active Surveillance Alternative to Immediate Biopsy and Surgery in Papillary Microcarcinoma

BACKGROUND

The 2015 American Thyroid Association thyroid cancer management guidelines endorse an active surveillance management approach as an alternative to immediate biopsy and surgery in subcentimeter thyroid nodules with highly suspicious ultrasonographic characteristics and in cytologically confirmed very low risk papillary thyroid cancer (PTC). However, the guidelines provide no specific recommendations with regard to the optimal selection of patients for an active surveillance management approach. This article describes a risk-stratified clinical decision-making framework that was developed by the thyroid cancer disease management team at Memorial Sloan Kettering Cancer Center as the lessons learned from Kuma Hospital in Japan were applied to a cohort of patients with probable or proven papillary microcarcinoma (PMC) who were being evaluated for an active surveillance management approach in the United States.

SUMMARY

A risk-stratified approach to the evaluation of patients with probable or proven PMC being considered for an active surveillance management approach requires an evaluation of three interrelated but distinct domains: (i) tumor/neck ultrasound characteristics (e.g., size of the primary tumor, the location of the tumor within the thyroid gland); (ii) patient characteristics (e.g., age, comorbidities, willingness to accept observation); and (iii) medical team characteristics (e.g., availability and experience of the multidisciplinary team). Based on an analysis of the critical factors within each of these domains, patients with probable or proven PTC can then be classified as ideal, appropriate, or inappropriate candidates for active surveillance.

CONCLUSION

Risk stratification utilizing the proposed decision-making framework will improve the ability of clinicians to recognize individual patients with proven or probable PMC who are most likely to benefit from an active surveillance management option while at the same time identifying patients with proven or probable PMC that would be better served with an upfront biopsy and surgical management approach.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Cardiac Effects of Thyrotropin Oversuppression with Levothyroxine in Young Women with Differentiated Thyroid Cancer

Background. We investigated the cardiac effects of TSH (thyroid-stimulating hormone) oversuppression in women with thyroidectomized differentiated thyroid cancer (DTC) during levothyroxine suppression therapy. Methods. Fourteen young female patients with DTC were enrolled. The duration of TSH-suppressive therapy was 5 to 9 years. They satisfied the following criteria: (1) a serum level of TSH < 0.1 mU/L in the intermediate-risk or TSH < 0.3 mU/L in the low-recurrence-risk group and (2) having been receiving a fixed dose of LT4 before the study. Controls matched for age, sex, and body mass index (BMI) were compared in terms of the levels of serum free T4, free T3, TSH, plasma N-terminal pro-brain natriuretic peptide (NT-pro-BNP), and cardiac functions and structures. Results. DTC patients and control subjects were well matched in heart rate and blood pressure. There were marked differences in serum TSH (P = 0.001) and free T4 (P = 0.002). However, there were no differences between the groups in serum free T3 and plasma NT-pro-BNP. Furthermore, there were nonsignificant differences in cardiac functions and structures between the groups. Conclusions. This study shows that TSH suppression therapy in women with DTC may be safe with respect to cardiac functions and structures despite intermittent oversuppression of TSH during long-term suppressive therapy. Trial Registration. This trial is registered with clinicaltrials.gov identifier NCT02645786.

Radioiodine Remnant Ablation: A Critical Review

Radioiodine remnant ablation (RRA) is considered a safe and effective method for eliminating residual thyroid tissue, as well as microscopic disease if at all present in thyroid bed following thyroidectomy. The rationale of RRA is that in the absence of thyroid tissue, serum thyroglobulin (Tg) measurement can be used as an excellent tumor marker. Other considerations are like the presence of significant remnant thyroid tissue makes detection and treatment of nodal or distant metastases difficult. Rarely, microscopic disease in the thyroid bed if not ablated, in the future, could be a source of anaplastic transformation. On the other hand, microscopic tumor emboli in distant sites could be the cause of distant metastasis too. The ablation of remnant tissue would in all probability eliminate these theoretical risks. It may be noted that all these are unproven contentious issues except postablation serum Tg estimation that could be a good tumor marker for detecting early biochemical recurrence in long-term follow-up strategy. Radioactive iodine is administered as a form of “adjuvant therapy” for remnant ablation. There have been several reports with regard to the administered dose for remnant ablation. The first report of a prospective randomized clinical trial was published from India by a prospective randomized study conducted at the All India Institute of Medical Sciences, New Delhi in the year 1996. The study reported that increasing the empirical ¹³¹I initial dose to more than 50 mCi results in plateauing of the dose-response curve and thus, conventional high-dose remnant ablation needs critical evaluation. Recently, two important studies were published: One from French group and the other from UK on a similar line. Interestingly, all three studies conducted in three different geographical regions of the world showed exactly similar conclusion. The new era of low-dose remnant ablation has taken a firm scientific footing across the continents.

Thyrotropin suppression increases the risk of osteoporosis without decreasing recurrence in ATA low- and intermediate-risk patients with differentiated thyroid carcinoma

BACKGROUND

Levothyroxine suppression of thyrotropin (TSH) is broadly applied to patients with thyroid cancer despite lack of consensus on the optimal TSH concentration necessary to reduce cancer recurrence while minimizing toxicity from subclinical hyperthyroidism. The objectives of this study were to examine the beneficial effects and the cardiac and skeletal toxicity of TSH suppression in well-differentiated thyroid carcinoma (DTC).

METHODS

A total of 771 patients (569 women) at ATA low or intermediate risk of recurrence, with a mean age of 48±14 years, and undergoing total thyroidectomy at a tertiary care center between 2000 and 2006 were followed for a median of six and a half years. They were divided into a suppressed TSH group (median TSH ≤0.4 mIU/L) and a nonsuppressed group (median TSH >0.4 mIU/L). Structural recurrence of thyroid cancer, postoperative atrial fibrillation (AF), and osteoporosis were examined in the two groups. Osteoporosis was only examined in women.

RESULTS

A total of 43/771 (5.6%) patients recurred, 29/739 (3.9%) patients were diagnosed with postoperative osteoporosis, and 17/756 (2.3 %) were diagnosed with postoperative AF. Despite similar rates of recurrence (HR 1.02, p=0.956 [CI 0.54-1.91]), patients treated to a median TSH ≤0.4 mIU/L were at increased postoperative risk of a composite outcome of AF and osteoporosis (HR 2.1, p=0.05 [CI 1.001-4.3]) compared to those not suppressed. A differential risk of AF alone (HR 0.78, p=0.63 [CI 0.3-2.1]) was not detected, but postoperative osteoporosis was increased among women with a suppressed TSH compared to those not suppressed (HR 3.5, p=0.023 [CI 1.2-10.2]). The increased risk of postoperative osteoporosis disappeared when the patient's median TSH was maintained around 1 mIU/L.

CONCLUSION

TSH suppression significantly increases the risk of postoperative osteoporosis without changing tumor recurrence in ATA low- and intermediate-risk patients with DTC. Future interventions should focus on avoiding harm in indolent disease.

Treatment with thyroid hormone

Thyroid hormone deficiency can have important repercussions. Treatment with thyroid hormone in replacement doses is essential in patients with hypothyroidism. In this review, we critically discuss the thyroid hormone formulations that are available and approaches to correct replacement therapy with thyroid hormone in primary and central hypothyroidism in different periods of life such as pregnancy, birth, infancy, childhood, and adolescence as well as in adult patients, the elderly, and in patients with comorbidities. Despite the frequent and long term use of l-T4, several studies have documented frequent under- and overtreatment during replacement therapy in hypothyroid patients. We assess the factors determining l-T4 requirements (sex, age, gender, menstrual status, body weight, and lean body mass), the major causes of failure to achieve optimal serum TSH levels in undertreated patients (poor patient compliance, timing of l-T4 administration, interferences with absorption, gastrointestinal diseases, and drugs), and the adverse consequences of unintentional TSH suppression in overtreated patients. Opinions differ regarding the treatment of mild thyroid hormone deficiency, and we examine the recent evidence favoring treatment of this condition. New data suggesting that combined therapy with T3 and T4 could be indicated in some patients with hypothyroidism are assessed, and the indications for TSH suppression with l-T4 in patients with euthyroid multinodular goiter and in those with differentiated thyroid cancer are reviewed. Lastly, we address the potential use of thyroid hormones or their analogs in obese patients and in severe cardiac diseases, dyslipidemia, and nonthyroidal illnesses.

Best practice for the management of pediatric thyroid cancer

The presentation of differentiated thyroid cancer in children often includes dissemination to lymph nodes. Despite this, the long-term prognosis is excellent with appropriate treatment. A few known hereditary syndromes are associated with paediatric thyroid cancer, although most tumours are sporadic. Ultrasound and cytology is used to evaluate suspect thyroid nodules, and treatment consists of surgery, radioactive iodine and thyroxine suppression therapy. Follow-up includes serum thyroglobulin measurements, serial ultrasounds of the neck, radioiodine whole body scans and occasionally other cross-sectional imaging or positron emission tomography. This review focuses on paediatric well differentiated follicular and papillary thyroid cancer, diagnosis and preoperative evaluation, underlying genetic mechanisms, surgery, other treatment options and follow-up.

Limited adequacy of thyroid cancer patient follow-up at a Canadian tertiary care centre

BACKGROUND

We sought to evaluate the adequacy of follow-up of thyroid cancer patients at a Canadian centre.

METHODS

We mailed a survey to the family physicians of thyroid cancer patients and analyzed the findings relative to follow-up guidelines published by the American Thyroid Association (ATA). Statistical significance between early and late follow-up patterns was analyzed using the χ(2) test.

RESULTS

Our survey response rate was 56.2% (91 of 162). The time from operation ranged from 1.24-7.13 (mean 3.96) years, and 87.9% of patients had undergone a physical exam within the previous year. Only 37.4% and 14% of patients had a serum thyroglobulin measurement within 6 and between 6 and 12 months before the survey, respectively. Thyroid simulating hormone (TSH) levels were measured within the prior 6 months in 67% of patients and between 6 and 12 months in 13.2%. The TSH levels were suppressed (< 0.1 μIU/L) in 24.2% of patients, 0.1-2 μIU/L in 44% and greater than 2 μIU/L in 17.6%. Ultrasonography was the most common imaging test performed.

CONCLUSION

There is significant variation in the follow-up patterns of patients with thyroid cancer, and there is considerable deviation from current ATA guidelines.

Current recommendations for levothyroxine treatment of differentiated thyroid cancer patients are not properly implemented in clinical practice

BACKGROUND

Levothyroxine (L-T4) treatment aims to minimize the risk of differentiated thyroid cancer (DTC) recurrence and should be tailored to patient risk stratification and potential morbidity from adverse effects.

AIM

To evaluate the effectiveness of current recommendations on L-T4 treatment of DTC patients in clinical practice.

MATERIAL AND METHODS

We submitted to in-person interviews and revised the charts of 139 low-risk (LR) and 57 not-low-risk (NLR) DTC patients. A second evaluation made 24-60 months after surgery reclassified 131 patients who maintained (thyroglobulin) Tg≤2 ng/dl with no evidence of relapse/recurrence as LR, whereas the remaining 65 cases were considered NLR.

RESULTS

Only 27% LR patients were appropriately controlled; 18% were kept suppressed; 49% maintained serum TSH levels between 0.11-0.4 mU/l; 21% had TSH=2.5- 4.5 mU/l; and 12% TSH>4.5 mU/l. Among the NLR patients, 24 (37%) of the patients presented serum TSH levels above goal, including 13 (20%) patients with TSH>4.5 mU/l. There were 4 NLR elders whose TSH levels were kept between 0.41 and 4.5 for medical reasons; likewise, 28 NLR patients maintained with low but not undetectable serum TSH levels had cardiovascular and/or bone risk factors, but all the remaining 24 NLR patients were not adequately controlled because of poor treatment compliance. On the other hand, 45% of 152 inappropriately controlled patients presented risks for bone fractures, including 33 patients kept with low serum TSH levels without medical indication.

CONCLUSION

We concluded that guidelines are not adequately applied and alternative strategies aiming to increase adherence are urgently needed for DTC patients.

[Potential risks of the adverse effects of thyrotropin suppression in differentiated thyroid carcinoma]

In patients with differentiated thyroid carcinoma, long-term inhibition of thyrotropin (TSH) secretion through levothyroxine administration is required when there is evidence of persistent or recurrent disease. In these cases, levothyroxine doses should be monitored to achieve the objectives of inhibiting TSH and avoiding clinical hyperthyroidism. The possibility that suppressive therapy may produce deleterious effects is still controversial, mainly in elderly patients. There are many studies on the potential harmful effects of suppressive therapy on various organs and systems with discrepant results. However, there is no scientific evidence that the clinical impact of these effects is significant.

Update on recent developments in the therapy of differentiated thyroid cancer

In the past decade, the management of differentiated thyroid carcinoma changed significantly and thus contributed to the improvement of the already favorable prognosis of this malignant disease. Surgical treatment techniques improved and the extent of initial surgery is more individualized. Radioiodine therapy is an essential part of therapeutic regimens in almost all cases, and the use of recombinant human thyroid-stimulating hormone has established for ablation of remnant tissue, treatment of iodine-positive cancer, and sensitive thyroglobulin measurement during follow-up. Risk stratification has become more important to plan treatment and follow-up individually, particularly to evaluate the need for thyroid-stimulating hormone suppression therapy. Especially for inoperable and radioiodine-negative thyroid carcinomas, novel treatment options such as tyrosine kinase inhibitor therapy have emerged. This article deals with the current options of optimal therapy regimens in differentiated thyroid carcinoma.

Benefits of thyrotropin suppression versus the risks of adverse effects in differentiated thyroid cancer

BACKGROUND

Despite clinical practice guidelines for the management of differentiated thyroid cancer (DTC), there are no recommendations on the optimal serum thyrotropin (TSH) concentration to reduce tumor recurrences and improve survival, while ensuring an optimal quality of life with minimal adverse effects. The aim of this review was to provide a risk-adapted management scheme for levothyroxine (L-T4) therapy in patients with DTC. The objective was to establish which patients require complete suppression of serum TSH levels, given their risk of recurrent or metastatic DTC, and how potential adverse effects on the heart and skeleton, induced by subclinical hyperthyroidism, in concert with advanced age and comorbidities, may influence the degree of TSH suppression.

SUMMARY

A risk-stratified approach to predict the rate of recurrence and death from thyroid cancer was based on the recently revised American Thyroid Association guidelines. A stratified approach to predict the risk from the adverse effects of L-T4 was devised, taking into account the age of the patient, as well as the presence of preexisting cardiovascular and skeletal risk factors that might predispose to the development of long-term adverse cardiovascular or skeletal outcomes, particularly increased heart rate and left ventricular mass, atrial fibrillation, and osteoporosis. Nine potential patient categories can be defined, with differing TSH targets for both initial and long-term L-T4 therapy.

CONCLUSION

Before deciding on the degree of TSH suppression during initial and long-term L-T4 treatment in patients with DTC, it is necessary to consider the aggressiveness of DTC, as well as the potential for adverse effects induced by iatrogenic subclinical hyperthyroidism. More aggressive TSH suppression is indicated in patients with high-risk disease or recurrent tumor, whereas less aggressive TSH suppression is reasonable in low-risk patients. In patients with high-risk DTC and an equally high risk of adverse effects, long-term treatment with L-T4 therapy should be individualized and balanced against the potential for adverse effects. In patients with an intermediate risk for thyroid cancer recurrence and a high risk of adverse effects of therapy, the degree of TSH suppression should be reevaluated during the follow-up period. Normalization of serum TSH is advisable for long-term treatment of disease-free elderly patients with DTC and significant comorbidities.

Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the publication of the American Thyroid Association's guidelines for the management of these disorders was published in 2006, a large amount of new information has become available, prompting a revision of the guidelines.

METHODS

Relevant articles through December 2008 were reviewed by the task force and categorized by topic and level of evidence according to a modified schema used by the United States Preventative Services Task Force.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to optimal surgical management, radioiodine remnant ablation, and suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using ultrasound and serum thyroglobulin as well as those related to management of recurrent and metastatic disease.

CONCLUSIONS

We created evidence-based recommendations in response to our appointment as an independent task force by the American Thyroid Association to assist in the clinical management of patients with thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Antitumor effects of arsenic trioxide in transformed human thyroid cells

BACKGROUND

To improve radioiodine treatment of metastasized differentiated thyroid carcinomas, substances that increase iodide uptake are needed. Many tumors are not responsive to retinoic acid as a differentiating agent. Therefore, identification of other differentiating substances is needed. Arsenic trioxide (ATO) was investigated for its potential to increase iodide uptake.

METHODS

The action of ATO on proliferation, differentiation, and apoptosis was evaluated in follicular and papillary thyroid carcinoma cell lines. To get insight into the mode of action of ATO, coincubations with inhibitors of the phosphoinositide 3 (PI3) kinase pathway (V-Akt Murine Thymoma Viral Oncogene Homolog 1, Akt inhibitors) were performed; glutathione (GSH) levels were determined, as well as synergistic effects of ATO with inhibitors of GSH metabolism, inductors of oxidative stress. As a potential additional target of the pleiotropic action of ATO, its effect on glucose uptake was investigated. The expression of sodium iodide symporter, pendrin, phospho-Akt, and glucose transporter 1 was studied to reveal a potential effect of ATO on the transcription of specific genes.

RESULTS

ATO reduced proliferation, increased iodide uptake and apoptosis, and, as an additional new mechanism, decreased glucose uptake in transformed thyrocytes. The pharmacological reduction of the amount of reduced GSH was effective in enhancing the differentiating action of ATO, whereas the combination of ATO with Akt-1 inhibitors reduced cell number but did not increase differentiation.

CONCLUSIONS

Our study suggests a new therapeutic option for postoperative treatment of radioiodine nonresponsive differentiated thyroid carcinomas.