Effect of Thyrotropin Suppression Therapy on Bone in Thyroid Cancer Patients

Comparison of Bone Mineral Density and Trabecular Bone Score in Patients with and without Vertebral Fractures and Differentiated Thyroid Cancer with Long-Term Serum Thyrotrophin-Suppressed Therapy

INTRODUCTION

The study of BMD provides only partial information on bone health in patients undergoing TSH suppression therapy due to differentiated thyroid cancer (DTC). The trabecular bone score (TBS), a new parameter assessing bone microarchitecture, is proposed for studying bone in this context. This study aimed to analyze their long-term use in patients with DTC.

METHODS

Bone mineral density (BMD) was measured by dual X-ray densitometry (DXA) and TBS was assessed with iNsigth software (version 2.0, MediImaps, France) in 145 postmenopausal patients with DTC. Vertebral fractures (VFs) were identified using a semi-quantitative X-ray method.

RESULTS

The BMD at the end of this study did not differ from the initial measurement. However, the TBS decreased from 1.35 ± 0.1 to 1.27 ± 0.1 (p = 0.002). Increased levels of PTH, osteocalcin, and bone alkaline phosphatase (BAP) were observed, suggesting enhanced bone remodeling. There was an increase in the prevalence of osteoporosis and osteopenia (40.6% and 16.5% to 46.6% and 18.6%, respectively). The proportion of patients with partially degraded and totally degraded TBS increased from 31% and 15.1% to 48.9% and 24.8% by the end of this study. Among the 30 patients with VFs, there were no significant differences in age, body mass index (BMI), calcium intake, alcohol consumption, smoking, radioiodine, therapy, or thyroid parameters compared to those without VFs. The odds ratio for VFs increased with osteopenia (OR 2.63). Combining TBS with BMD did not improve discrimination.

CONCLUSIONS

The TBS decreased while the BMD remained unchanged. The percentage of patients with osteoporosis and osteopenia, whether partially degraded or totally degraded, increased by the end of this study. The predominant discordance was found in partially degraded microarchitectures, with a higher proportion of osteopenic patients compared to those with normal or osteoporotic bone density. The AUC of the combination of TBS and BMD did not enhance discrimination. TBS, radioactive iodine therapy, and sedentary lifestyle emerged as the main distinguishing factors for DTC patients with VFs.

Evaluation and Management of Bone Health in Patients with Thyroid Diseases: A Position Statement of the Korean Thyroid Association

Thyroid hormones play an important physiological role in maintaining adult bone structure and strength. Consequently, thyroid dysfunction is related to skeletal outcomes. Overt hyperthyroidism is an established cause of high bone turnover with accelerated bone loss, leading to osteoporosis and increased fracture risk. Hyperthyroidism induced by thyroid-stimulating hormone-suppressive therapy in patients with differentiated thyroid cancer is a cause of secondary osteoporosis. In contrast, there is a lack of evidence on the negative impact of hypothyroidism on bone health. Considering the clinical updates on the importance of bone health in thyroid dysfunction, the Task Force from the Clinical Practice Guidelines Development Committee of the Korean Thyroid Association recently developed a position statement on the evaluation and management of bone health of patients with thyroid diseases, particularly focused on endogenous hyperthyroidism and thyroid-stimulating hormone-suppressive therapy-associated hyperthyroidism in patients with differentiated thyroid cancer. Herein, we review the Korean Thyroid Association's position statement on the evaluation and management of bone health associated with thyroid diseases.

Understanding Worry About Risks Associated With Thyroid Hormone Therapy: A National Survey of Endocrinologists, Family Physicians, and Geriatricians

OBJECTIVE

Thyroid hormone use is widespread, and prior studies have shown that over- and undertreatment with thyroid hormone are common. Our objective was to understand physician worry regarding risks associated with thyroid hormone therapy, specifically overtreatment or undertreatment.

METHODS

A nationwide survey was administered to physician members of the Endocrine Society, the American Academy of Family Practice, and the American Geriatrics Society. Participants were asked how often they were worried about various risks that may be associated with thyroid hormone over- or undertreatment, that is, cardiovascular complications, bone complications, and poor quality of life due to overtreatment or undertreatment with thyroid hormone. Multivariable regression analyses were conducted to determine physician characteristics associated with each worry.

RESULTS

The response rate was 63% (359 of 566); of those who responded, 128 (36%) were primary care physicians, 114 (32%) were endocrinologists, and 113 (32%) were geriatricians. Overall, 74 (21%) physicians reported that they frequently or always worried about cardiovascular complications, 74 (21%) about bone complications, 111 (31%) about the poor quality of life due to symptoms from undertreatment with thyroid hormone, and 87 (24%) about the poor quality of life due to symptoms from overtreatment with thyroid hormone. Endocrinologists were more likely to frequently or always worry about the patients' poor quality of life due to symptoms from overtreatment (odds ratio, 2.05; 95% confidence interval, 1.09-3.93) compared with primary care physicians.

CONCLUSION

Up to one third of the physicians frequently or always worried about risks resulting from the thyroid hormone overtreatment or undertreatment. More research is needed across specialties to understand physician perceptions of how thyroid hormone therapy impacts the patients' quality of life.

Personalized treatment for differentiated thyroid cancer: current data and new perspectives

More conservative and personalized treatment options have been developed in recent years to face the rising diagnosis of low-risk differentiated thyroid carcinoma (DTC). The present review describes the change towards a more risk-adapted management either in the treatment or in the follow-up of DTC. Particular attention is given to the innovations introduced by the latest guidelines for low-risk tumors, starting from the most appropriate extension of surgery up to the postoperative management. The emerging role of active surveillance for low-risk microcarcinoma is discussed, as well as the development of percutaneous strategies in the setting of malignant thyroid disease. The recent use of approved new systemic target therapies for advanced radioiodine refractory thyroid cancer is reported, together with the description of new compounds in trial. Finally, we provide some considerations to improve the risk evaluation in a presurgical setting, especially related to the rising role of genetics, to enable better risk-based cancer management and personalized treatment choices.

Understanding Osteoporosis Screening Practices in Men: A Nationwide Physician Survey

OBJECTIVE

To understand osteoporosis screening practices, particularly in men, by a diverse cohort of physicians, including primary care physicians, endocrinologists, and geriatricians.

METHODS

We surveyed randomly selected members of the American Academy of Family Practice, Endocrine Society, and American Geriatrics Society. Respondents were asked to rate how often they would screen for osteoporosis in four different clinical scenarios by ordering a bone density scan. Multivariable logistic regression analyses were conducted to determine factors associated with offering osteoporosis screening in men in each clinical scenario. Physicians were also asked to note factors that would lead to osteoporosis screening in men.

RESULTS

Response rate was 63% (359/566). While 90% respondents reported that they would always or frequently screen for osteoporosis in a 65-year-old post-menopausal woman, only 22% reported they would screen a 74-year-old man with no significant past medical history. Endocrinologists were more likely to screen a 74-year-old man compared to primary care physicians (odds ratio, 2.32; 95% confidence interval, 1.10 to 4.88). In addition to chronic steroid use (94%), history of nontraumatic fractures (88%), and androgen-deprivation therapy for prostate cancer (82%), more than half the physicians reported suppressive doses of thyroid hormone (64%) and history of falls (52%) as factors leading to screening for osteoporosis in men.

CONCLUSIONS

Our survey results highlight heterogeneity in osteoporosis screening in men, with underscreening in some scenarios compared to women, and identify factors that lead to screening in men. These findings can help design interventions to improve osteoporosis screening in men.

TSH suppressive therapy and bone

Thyroid hormones stimulate bone turnover in adults by increasing osteoclastic bone resorption. TSH suppressive therapy is usually applied in patients with differentiated thyroid cancer (DTC) to improve the disease outcome. Over the last decades several authors have closely monitored the potential harm suffered by the skeletal system. Several studies and meta-analyses have shown that chronic TSH suppressive therapy is safe in premenopausal women and men. Conversely, in postmenopausal women TSH suppressive therapy is associated with a decrease of bone mineral density, deterioration of bone architecture (quantitative CT, QCT; trabecular bone score, TBS), and, possibly, an increased risk of fractures. The TSH receptor is expressed in bone cells and the results of experimental studies in TSH receptor knockout mice and humans on whether low TSH levels, as opposed to solely high thyroid hormone levels, might contribute to bone loss in endogenous or exogenous thyrotoxicosis remain controversial. Recent guidelines on the use of TSH suppressive therapy in patients with DTC give value not only to its benefit on the outcome of the disease, but also to the risks associated with exogenous thyrotoxicosis, namely menopause, osteopenia or osteoporosis, age >60 years, and history of atrial fibrillation. Bone health (BMD and/or preferably TBS) should be evaluated in postmenopausal women under chronic TSH suppressive therapy or in those patients planning to be treated for several years. Antiresorptive therapy could also be considered in selected cases (increased risk of fracture or significant decline of BMD/TBS during therapy) to prevent bone loss.

Trabecular bone deterioration in differentiated thyroid cancer: Impact of long-term TSH suppressive therapy

Background

Conflicting results has been reported regard osteoporosis and fractures in patients with Differentiated Thyroid Cancer (DTC). Our objective was to evaluate the long‐term effects of TSH suppression therapy with Levothyroxine (LT4) on trabecular bone score (TBS) and bone mineral density (BMD) in females with DTC after thyroidectomy.

Methods

About 145 women with resected DTC and receiving long‐term TSH therapy, were stratified according to the degree of TSH suppression. Mean duration of follow‐up was 12.3 ± 6.1 years. BMD and TBS, were assessed using dual‐energy X‐ray absorptiometry (DXA) and TBS iNsight (Med‐Imaps), at baseline (1‐3 months after surgery) and at the final study visit.

Results

In patients stratified by duration of TSH suppression therapy (Group I, 5‐10 years; Group II, >10 years), slight increases from baseline TSH levels were observed. Significant decreases in LS‐BMD and FN‐BMD were seen in patients after >10 years. TBS values were lower in Groups I (1.289 ± 0.122) and II (1.259 ± 0.129) compared with baseline values (P = .0001, both groups). Regarding the degree of TSH suppression, TBS was significantly reduced in those with TSH < 0.1 µU/mL (P = .0086), and not in patients with TSH suppression of 0.1.‐0.5 or >0.5 µU/mL.

Conclusions

We found deterioration of trabecular structure in patients with DTC and TSH suppression therapy below 0.1 µU/mL and after 5‐10 years of follow‐up. Significant changes in BMD according to TSH levels were not observed. Trabecular Bone Score is a useful technique for identifying thyroid cancer patients with risk of bone deterioration.

Association between Geriatric Nutrition Risk Index and Skeletal Muscle Mass Index with Bone Mineral Density in Post-Menopausal Women Who Have Undergone Total Thyroidectomy

Background: Osteoporosis is highly prevalent in postmenopausal women and may result in fractures and disabilities. Total thyroidectomy has also been associated with loss of bone mass. The aim of this cross-sectional study was to evaluate associations among nutritional status, skeletal muscle index and markers of bone turnover to bone mineral density in postmenopausal women who had undergone total thyroidectomy. Methods: Fifty postmenopausal women who had undergone total thyroidectomy were included. Body composition was measured using dual-energy X-ray absorptiometry (DXA). The Geriatric Nutritional Risk Index (GNRI) was calculated using baseline body weight and serum albumin level. Skeletal muscle mass index was calculated as the appendicular skeletal muscle mass (ASM) divided by the height squared and assessed using DXA. Results. Multivariate stepwise linear regression analysis showed that a low GNRI was significantly associated with low lumbar spine bone mineral density (BMD) and T-score, and that a low ASM/height² was significantly associated with low femoral neck BMD and T-score. A low vitamin D level was significantly associated with low femoral neck BMD and T-score and low total hip BMD and T-score. A high bone alkaline phosphatase (ALP) level was significantly associated with low femoral neck T-score and low total hip BMD and T-score. A low insulin-like growth factor-1 (IGF-1) was significantly associated with low total hip BMD and T-score. Conclusion: In the postmenopausal women who had undergone total thyroidectomy in this study, BMD was positively associated with GNRI, skeletal muscle mass index, and levels of vitamin D and serum IGF-1, and inversely associated with bone ALP level. Nutritional status, skeletal muscle mass index and bone turnover biomarkers can be used to early identify patients with a high risk of osteoporosis in this high-risk group.

Patient Requests for Tests and Treatments Impact Physician Management of Hypothyroidism

Background: Levothyroxine is one of the most commonly prescribed medications in the United States. Although prior research focused on over- and undertreatment and patient dissatisfaction with thyroid hormone, little is known about physician-reported barriers to managing thyroid hormone therapy. In addition, the impact of patient requests for tests and treatments on hypothyroidism management remains unexplored. Methods: We randomly surveyed physician members of the Endocrine Society, American Academy of Family Practice and American Geriatrics Society. Respondents were asked to rate barriers to management of thyroid hormone therapy. We conducted multivariable logistic regression analyses to determine correlates with physician report of the most commonly reported barriers, including patient requests. Results: Response rate was 63% (359/566). Almost half of the physicians reported that patient requests for tests and treatments were somewhat to very likely to being a barrier to appropriate management of thyroid hormone therapy (46%). Endocrinologists (odds ratio [OR] = 2.29 [95% confidence interval, CI 1.03-5.23], compared with primary care physicians) and physicians with more than 25% of patients on thyroid hormone therapy per year (OR = 1.90 [CI 1.05-3.46], compared with those with <25% patients per year) were more likely to report patient requests as a barrier. Physicians with more years in practice were less likely to do so (11-20 years: OR = 0.44 [CI 0.21-0.89]; >20 years: OR = 0.24 [CI 0.12-0.46], compared with ≤10 years). Physician-reported patient requests included requests for preparations other than synthetic thyroxine (52%), adjusting thyroid hormone dose based on symptoms when biochemically euthyroid (52%), maintaining thyrotropin level below the reference range (32%), and adjusting dose according to serum T3 level (21%). Physicians who reported receiving patient requests for the former three unconventional practices were more likely to execute them (p < 0.001, p = 0.014, p < 0.001, respectively). Conclusions: Physicians reported patient requests for tests and treatments as a common barrier to appropriate thyroid hormone management. In some scenarios, physician adherence to patient requests may be a driver for inappropriate care and lead to harm. Understanding physician-reported barriers to thyroid hormone management and factors associated with physician perception that patient requests are a barrier is key to improving patient care.

Risk of Osteoporosis and Fractures in Patients with Thyroid Cancer: A Case-Control Study in U.S. Veterans

BACKGROUND

Data on osteoporosis and fractures in patients with thyroid cancer, especially men, are conflicting. Our objective was to determine osteoporosis and fracture risk in U.S. veterans with thyroid cancer.

MATERIALS AND METHODS

This is a case-control study using the Veterans Health Administration Corporate Data Warehouse (2004-2013). Patients with thyroid cancer (n = 10,370) and controls (n = 10,370) were matched by age, sex, weight, and steroid use. Generalized linear mixed-effects regression model was used to compare the two groups in terms of osteoporosis and fracture risk. Next, subgroup analysis of the patients with thyroid cancer using longitudinal thyroid-stimulating hormone (TSH) was performed to determine its effect on risk of osteoporosis and fractures. Other covariates included patient age, sex, median household income, comorbidities, and steroid and androgen use.

RESULTS

Compared with controls, osteoporosis, but not fractures, was more frequent in patients with thyroid cancer (7.3% vs. 5.3%; odds ratio [OR], 1.33; 95% confidence interval [CI], 1.18-1.49) when controlling for median household income, Charlson/Deyo comorbidity score, and androgen use. Subgroup analysis of patients with thyroid cancer demonstrated that lower TSH (OR, 0.93; 95% CI, 0.90-0.97), female sex (OR, 4.24; 95% CI, 3.53-5.10), older age (e.g., ≥85 years: OR, 17.18; 95% CI, 11.12-26.54 compared with <50 years), and androgen use (OR, 1.63; 95% CI, 1.18-2.23) were associated with osteoporosis. Serum TSH was not associated with fractures (OR, 1.01; 95% CI, 0.96-1.07).

CONCLUSION

Osteoporosis, but not fractures, was more common in U.S. veterans with thyroid cancer than controls. Multiple factors may be contributory, with low TSH playing a small role.

IMPLICATIONS FOR PRACTICE

Data on osteoporosis and fragility fractures in patients with thyroid cancer, especially in men, are limited and conflicting. Because of excellent survival rates, the number of thyroid cancer survivors is growing and more individuals may experience long-term effects from the cancer itself and its treatments, such as osteoporosis and fractures. The present study offers unique insight on the risk for osteoporosis and fractures in a largely male thyroid cancer cohort. Physicians who participate in the long-term care of patients with thyroid cancer should take into consideration a variety of factors in addition to TSH level when considering risk for osteoporosis.

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.

Effect of radioactive iodine-induced hypothyroidism on longitudinal bone growth during puberty in immature female rats

Thyroid cancer in children, the most common endocrine malignancy, shows aggressive behavior and has a high recurrence rate after surgical ablation. Radioactive iodine (RAI) treatment is the most effective primary modality for medical ablation of juvenile thyroid cancer, and leads to intentional hypothyroidism. Although several negative impacts of hypothyroidism have been reported in children in response to other antithyroid agents, the combined effects of RAI exposure and hypothyroidism, on growing bones specifically, are unknown. In this study, we investigated the effect of RAI-induced hypothyroidism on the long bones during the pubertal growth spurt using immature female rats. Female Sprague-Dawley rats were randomly divided into a control group, and an RAI-treated group fed with RAI (0.37 MBq/g body weight) twice via gavage. After 4 weeks, we observed a significantly-reduced serum free thyroxine level in the RAI group. The latter group also displayed decreased body weight gain compared to the control. In addition, the lengths of long bones, such as the leg bones and vertebral column, as well as bone mineral content, were reduced in the RAI-treated animals. Our results confirm the negative impacts of RAI-induced thyroid deficiency during puberty on longitudinal bone growth and bone mineralization.

Low trabecular bone score in postmenopausal women with differentiated thyroid carcinoma after long-term TSH suppressive therapy

The effect of thyroid suppression therapy (TST) on trabecular bone scores (TBS) and bone mineral density (BMD) in thyroidectomized women with differentiated thyroid carcinoma (DTC) on long-term follow-up is presently not conclusive.

PATIENTS AND METHODS

We carried out a study in 61 premenopausal and 84 postmenopausal Caucasian women with DTC. Serum biochemistry, bone markers, TBS, BMD, and bone fractures were evaluated 1-3 months post surgery and after a median follow-up of 10 years.

RESULTS

In the final study, patients belonged to Group I Premenopausal (n = 14) who remained in this status; Group II Premenopausal who became postmenopausal (n = 47); Group III patients who were and continued as postmenopausal (n = 84). Baseline premenopausal patients had a normal TBS mean value of 1.39 ± 0.14 significantly higher than that found in postmenopausal 1.31 ± 0.12 (p = 001). In the final study, premenopausal patients continued to have a normal TBS of 1.46 ± 0.08 compared to the significantly lower value of postmenopausal patients 1.25 ± 0.11 (p = 0.0009). Lumbar BMD (L-BMD) loss after the long-term study was significant in Group II (0.99 g/cm² ± 0.13 vs. 0.91 ± 0.12 g/cm², p < 0.0001) and there was a slight, but not significant, bone loss in Group I (1.00 ± 0.12 vs. 0.98 ± 0.11, p = 0.1936) and in Group III (0.86 ± 0.12 vs. 0.84 ± 0.15, p = 0.1924) compared with baseline values.

CONCLUSION

Longer-term suppression therapy in female patients with DTC did not increase significantly the risk of bone loss, although we found in postmenopausal patients deterioration of bone microarchitecture. TBS study should be considered in the evaluation of postmenopausal DTC patients on long-term DTC for the evaluation of the risk of fractures.

Loss of sorting nexin 5 stabilizes internalized growth factor receptors to promote thyroid cancer progression

Thyroid carcinoma is the most common endocrine malignancy and its prevalence has recently been increasing worldwide. We previously reported that the level of sorting nexin 5 (Snx5), an endosomal translocator, is preferentially decreased during the progression of well-differentiated thyroid carcinoma into poorly differentiated carcinoma. To address the functional role of Snx5 in the development and progression of thyroid carcinoma, we established Snx5-deficient (Snx5^-/- ) mice. In comparison to wild-type (Snx5^+/+ ) mice, Snx5^-/- mice showed enlarged thyroid glands that consisted of thyrocytes with large irregular-shaped vacuoles. Snx5^-/- thyrocytes exhibited a higher growth potential and higher sensitivity to thyroid-stimulating hormone (TSH). A high content of early endosomes enriched with TSH receptors was found in Snx5^-/- thyrocytes, suggesting that loss of Snx5 caused retention of the TSH receptor (TSHR) in response to TSH. Similar data were found for internalized EGF in primary thyrocytes. The increased TSH sensitivities in Snx5^-/- thyrocytes were also confirmed by results showing that Snx5^-/- mice steadily developed thyroid tumors with high metastatic potential under high TSH. Furthermore, a thyroid cancer model using carcinogen and an anti-thyroidal agent revealed that Snx5^-/- mice developed metastasizing thyroid tumors with activation of MAP kinase and AKT pathways, which are postulated to be major pathways of malignant progression of human thyroid carcinoma. Our results suggest that thyrocytes require Snx5 to lessen tumorigenic signaling driven by TSH, which is a major risk factor for thyroid carcinoma. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.