Effects of thyroid-stimulating hormone suppression after thyroidectomy for thyroid cancer on bone mineral density in postmenopausal women: a systematic review and meta-analysis

Tailoring TSH suppression in differentiated thyroid carcinoma: evidence, controversies, and future directions

PURPOSE

This review focus on the controversial benefits of thyroid hormone suppression therapy (THST) in differentiated thyroid carcinoma (DTC) and its associated risks, highlighting the need for individualized strategies to optimize therapeutic outcomes and guide future research.

METHODS

A systematic literature search on TSH suppression in DTC over the past 10 years was conducted, prioritizing RCTs, large cohort studies, and non-inferiority trials, with additional references identified from retrieved articles.

RESULTS

Tailored postoperative TSH strategies should consider factors such as risk stratification, treatment modality, histologic subtype, and adverse effect risks. In this context, mechanistic studies offer potential insights that could inform personalized TSH management, though further validation is required. Clinical evidence on THST in DTC remains controversial, particularly for high-risk patients, where support for stringent TSH suppression (<0.1 mU/L) is limited. Data for intermediate-risk DTC are insufficient due to cohort heterogeneity, while TSH suppression in low-risk DTC is largely discouraged. The well-documented adverse effects of excessive THST, including cardiovascular complications and osteoporosis, further provide a strong rationale against its routine use. Additionally, achieving and maintaining target TSH levels in real-world practice remains challenging, underscoring the need for refined approaches.

CONCLUSION

Current evidence provides limited support for the TSH targets recommended by the 2015 ATA guidelines. Optimizing postoperative TSH management should account for individualized factors, including risk stratification, treatment modalities, histologic subtypes, and susceptibility to adverse effects. Future research should prioritize well-designed studies with clearly defined suppression levels and appropriate confounder adjustments, emphasizing personalized approaches to balance therapeutic benefits and adverse effects.

Risk of Osteoporotic Fractures among Patients with Thyroid Cancer: A Nationwide Population-Based Cohort Study

BACKGRUOUND

The associations between thyroid cancer and skeletal outcomes have not been thoroughly investigated. We aimed to investigate the risk of osteoporotic fractures in patients with thyroid cancer compared to that in a matched control group.

METHODS

This retrospective cohort study included 2,514 patients with thyroid cancer and 75,420 matched controls from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC, 2006-2019). The rates of osteoporotic fractures were analyzed, and associations with the levothyroxine dose were evaluated.

RESULTS

Patients with thyroid cancer had a significantly lower risk of fracture than did the control group (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69 to 0.94; P=0.006). Patients diagnosed with thyroid cancer after the age of 50 years (older cancer group) had a significantly lower risk of fracture than did those in the control group (HR, 0.72; 95% CI, 0.6 to 0.85; P<0.001), especially those diagnosed with spinal fractures (HR, 0.66; 95% CI, 0.51 to 0.85; P=0.001). Patients in the older cancer group started osteoporosis treatment earlier than did those in the control group (65.5±7.5 years vs. 67.3±7.6 years, P<0.001). Additionally, a lower dose of levothyroxine was associated with a reduced risk of fractures.

CONCLUSION

In the clinical setting, the risk of fracture in women diagnosed with thyroid cancer after the age of 50 years was lower than that in the control group, which was caused by more proactive osteoporosis treatment in postmenopausal women with thyroid cancer.

Feasibility of Lobectomy in Selected Patients with Unilateral N1b Papillary Thyroid Cancer

BACKGROUND

Total thyroidectomy (TT) is usually recommended for unilateral papillary thyroid cancer (PTC) with lateral lymph node metastasis (LLNM), but no significant improvement in recurrence-free survival (RFS) is seen upon treatment. As an initial surgery, lobectomy may have advantages in appropriately selected unilateral PTC with ipsilateral LLNM.

OBJECTIVE

This study aimed to explore the feasibility of lobectomy for selected unilateral PTC with ipsilateral LLNM.

METHODS

From January 2014 to December 2021, we retrospectively reviewed patients with PTC and LLNM who were treated at our center. Patients preoperatively diagnosed with unilateral PTC and ipsilateral LLNM were recruited. Overall, 102 patients who chose lobectomy as their initial surgery were included in the lobectomy group and 96 patients who chose TT were included in the control group, defined as the TT group.

RESULTS

The mean follow-up time of the lobectomy group was 47.5 ± 22.2 months. Patients in the lobectomy group had a significantly lower rate of hypoparathyroidism than those in the TT group (0% vs. 11.5%; p < 0.001). RFS after lobectomy was comparable with that after TT according to Kaplan-Meier curve analysis (log-rank p = 0.80). Lobectomy achieved a significantly lower incidence of unsatisfactory TSH control than TT (5.9% vs. 20.8%; p = 0.006).

CONCLUSIONS

Lobectomy may be an appropriate initial therapy for selected unilateral PTC with ipsilateral LLNM. A randomized prospective study with long-term follow-up is warranted.

Effects of levothyroxine therapy on bone and mineral metabolism in hypothyroidism: a systematic review and meta-analysis

BACKGROUND

Thyroid hormone plays an important role in accumulating bone development and regulating bone metabolism. It is established that hypothyroidism is linked to increased risk of osteoporosis and fracture. However, the effects of levothyroxine (LT4) treatment on bone for hypothyroid patients remain controversial.

METHODS

A systematical search was conducted of several databases, from inception until December 9, 2022, and updated the search using the same search strategy on October 30, 2024, for studies evaluating the effects of LT4 treatment on bone in hypothyroidism including subclinical hypothyroidism (SCH) and overt hypothyroidism (OH). The data were reported using a random-effects model with a standardized mean difference (SMD) and 95% conference interval (CI).

RESULTS

Thirteen of the 5996 published articles were included in this meta-analysis. No significance was found in bone mineral density (BMD) at the lumbar spine between SCH patients treated with LT4 and control group either at baseline or after intervention. For OH, BMD at the lumbar spine was statistically lower in LT4 treatment group compared with healthy controls (HCs) (SMD: -0.28, 95%CI: -0.55, -0.02, P = 0.040, I2 = 52%). There were no differences in BMD at the femoral neck, trochanter, and Ward's triangle between OH patients treated with LT4 and HCs. In addition, BMD at the lumbar spine was significantly lower in males with OH undergoing LT4 treatment for a duration of less than five years compared to those treated over five years. Nevertheless, no significant differences were found in bone metabolism biomarkers between OH patients treated with LT4 and HCs.

CONCLUSION

This systematic review and meta-analysis demonstrated that there is a slight adverse effect of LT4 replacement therapy on bone and mineral metabolism in patients with OH, while no observed effect was found in SCH patients.

Association between serum TSH concentration and bone mineral density: an umbrella review

INTRODUCTION

The aim of this study was to summarize the results of previous studies, standardize the data, and present new statistical results in order to provide physicians with clinically significant outcomes regarding the association between serum TSH concentration and bone mineral density (BMD).

METHODS

To perform this umbrella review, a systematic search was conducted in which major online medical databases, such as PubMed, Web of Science, Embase, Scopus, Cochrane Library, and Google Scholar, were searched for meta-analyses and systematic reviews regarding the effect of TSH on BMD. Furthermore, all primary studies were screened for statistical analysis.

RESULTS

The statistical outcomes of the present study were based on the data of 75,898 patients. The pooled risk ratio of any kind of fracture in patients with subclinical hyperthyroidism was estimated to be 1.36 (95% CI: 1.18-1.56; p < 0.001). The SMD for BMD in the distal radius in male patients receiving L-thyroxine suppression therapy was estimated to be -0.61 (95% CI: -1.10-(-0.11); p = 0.02). Furthermore, the pooled risk ratio of any fracture in patients receiving L-thyroxine suppression therapy was estimated to be 1.98 (95% CI: 0.98 - 3.98; p = 0.06). In these patients, the BMD may significantly differ from that in non-treated patients. However, the difference depends on the type of bone.

CONCLUSIONS

Our data confirmed that subclinical hyperthyroidism has a detrimental effect on bones, causing decreased BMD. Based on the obtained results, the authors suggest that a reduced TSH serum level itself may be an individual factor associated with decreased BMD and, thus, with a greater risk of bone fracture. Nevertheless, it should be noted that the effects of TSH suppression therapy differ between areas of interest for assessing BMD. Furthermore, the results have shown that this issue may, in specific areas, concern not only postmenopausal women but also male patients. These conclusions should contribute to a careful consideration of the application of TSH suppressive therapy in all patients. Particular attention should be given to patients after DTC, while all the advantages and disadvantages of implementing L-thyroxine therapy should be individually considered.

Body composition changes in patients with differentiated thyroid cancer after iodine-131 treatment and short-term levothyroxine replacement and suppression therapy

PURPOSE

The purposes of this study were to assess the changes in body composition in patients who underwent thyroidectomy due to differentiated thyroid cancer (DTC) after radioactive iodine therapy (RAI) and short-term levothyroxine (LT4) supplementation and to explore the correlations between body composition distribution and corresponding blood indices.

METHODS

Fifty-seven thyroidectomized DTC patients were included. Serum was tested for several biochemical indices of thyroid function, lipids, and bone metabolism, and body composition parameters were measured via dual-energy X-ray absorptiometry before and 4-6 weeks after RAI and LT4 supplementation.

RESULTS

The body composition of DTC patients changed after RAI. Fat mass in all parts of the body decreased (range of relative change (RRC) -12.97--2.80%). Bone mineral content (BMC) increased throughout the body (relative change (RC) 12.12%), head (RC 36.23%), pelvis (RC 9.00%), and legs (RC 3.15%). Similarly, bone mineral density (BMD) increased in different regions (RRC 3.60-26.43%), except for the arms. Notably, lean mass in the arms (RC 4.30%) and legs (RC 3.67%) increased, while that in the head decreased (RC -2.75%), while total lean mass did not change at 4-6 weeks after LT4 supplementation. Furthermore, changes in fat distribution in the android region were related to the changes in total cholesterol (r = -0.390) and low-density lipoprotein cholesterol (r = -0.354), and changes in the BMC and BMD of the lumbar spine were positively associated with the changes in calcitonin (r = 0.302 and 0.325, respectively).

CONCLUSIONS

After RAI and short-term LT4 supplementation in DTC patients, body composition rapidly and positively changed and was characterized by decreased fat mass and increased BMC and BMD.

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.

Mcl-1 mediates intrinsic resistance to RAF inhibitors in mutant BRAF papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most frequent form of thyroid cancer. PTC commonly presents with mutations of the serine/threonine kinase BRAF (BRAFV600E), which drive ERK1/2 pathway activation to support growth and suppress apoptosis. PTC patients often undergo surgical resection; however, since the average age of PTC patients is under 50, adverse effects associated with prolonged maintenance therapy following total thyroidectomy are a concern. The development of mutant-selective BRAF inhibitors (BRAFi), like vemurafenib, has been efficacious in patients with metastatic melanoma, but the response rate is low for mutant BRAF PTC patients. Here, we assay the therapeutic response of BRAFi in a panel of human PTC cell lines and freshly biopsied patient samples. We observed heterogeneous responses to BRAFi, and multi-omic comparisons between susceptible and resistant mutant BRAF PTC revealed overrepresented stress response pathways and the absence of compensatory RTK activation - features that may underpin innate resistance. Importantly, resistant cell lines and patient samples had increased hallmarks of failed apoptosis; a cellular state defined by sublethal caspase activation and DNA damage. Further analysis suggests that the failed apoptotic phenotypes may have features of "minority mitochondrial outer membrane permeabilization (MOMP)" - a stress-related response characterized by fragmented and porous mitochondria known to contribute to cancer aggressiveness. We found that cells presenting with minority MOMP-like phenotypes are dependent on the apoptotic regulator, Mcl-1, as treatment with the Mcl-1 inhibitor, AZD5991, potently induced cell death in resistant cells. Furthermore, PI3K/AKT inhibitors sensitized resistant cells to BRAFi; an effect that was at least in part associated with reduced Mcl-1 levels. Together, these data implicate minority MOMP as a mechanism associated with intrinsic drug resistance and underscore the benefits of targeting Mcl-1 in mutant BRAF PTC.

Effect of Thyroid-Stimulating Hormone Suppression Therapy on Cardiac Structure and Function in Patients With Differentiated Thyroid Cancer After Thyroidectomy: A Systematic Review and Meta-Analysis

OBJECTIVE

We aimed to evaluate the effects of thyroid-stimulating hormone (TSH) suppression therapy on cardiac structure and function in patients with differentiated thyroid cancer (DTC) following thyroidectomy.

METHODS

Two investigators independently searched the PubMed, Embase, Cochrane Library, and Web of Science databases for relevant studies published from inception to January 6, 2023, without any restrictions on language. Standard mean differences and 95% confidence intervals were calculated using fixed or random effects models. Thirteen clinical outcomes were analyzed, mainly evaluating cardiac morphology, systolic function, and diastolic function.

RESULTS

Thirteen studies were included in the quantitative analysis. Compared to healthy controls, left ventricular mass index, left ventricular posterior wall thickness, interventricular septal thickness, and isovolumic relaxation time values increased; the ratio of E-wave velocity to A-wave velocity and E-wave velocity values decreased. The left ventricular ejection fraction and cardiac output did not change in patients with DTC who underwent long-term TSH suppression therapy. Interventricular septal thickness values were significantly correlated with the duration of TSH suppression therapy.

CONCLUSION

Long-term TSH suppression therapy leads to cardiac hypertrophy and impaired cardiac diastolic function in patients with DTC. These changes may be related to the duration of TSH suppression therapy. Large prospective studies with long follow-up periods are needed to validate these findings.

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.

Fracture risk and assessment in adults with cancer

Individuals with cancer face unique risk factors for osteoporosis and fractures. Clinicians must consider the additive effects of cancer-specific factors, including treatment-induced bone loss, and premorbid fracture risk, utilizing FRAX score and bone mineral densitometry when available. Pharmacologic therapy should be offered as per cancer-specific guidelines, when available, or local general osteoporosis guidelines informed by clinical judgment and patient preferences. Our objective was to review and summarize the epidemiologic burden of osteoporotic fracture risk and fracture risk assessment in adults with cancer, and recommended treatment thresholds for cancer treatment-induced bone loss, with specific focus on breast, prostate, thyroid, gynecological, multiple myeloma, and hematopoietic stem cell transplant. This narrative review was informed by PubMed searches to July 25, 2022, that combined terms for cancer, stem cell transplantation, fracture, bone mineral density (BMD), trabecular bone score, FRAX, Garvan nomogram or fracture risk calculator, QFracture, prediction, and risk factors. The literature informs that cancer can impact bone health in numerous ways, leading to both systemic and localized decreases in BMD. Many cancer treatments can have detrimental effects on bone health. In particular, hormone deprivation therapies for hormone-responsive cancers such as breast cancer and prostate cancer, and hematopoietic stem cell transplant for hematologic malignancies, adversely affect bone turnover, resulting in osteoporosis and fractures. Surgical treatments such as hysterectomy with bilateral salpingo-oophorectomy for gynecological cancers can also lead to deleterious effects on bone health. Radiation therapy is well documented to cause localized bone loss and fractures. Few studies have validated the use of fracture risk prediction tools in the cancer population. Guidelines on cancer-specific treatment thresholds are limited, and major knowledge gaps still exist in fracture risk and fracture risk assessment in patients with cancer. Despite the limitations of current knowledge on fracture risk assessment and treatment thresholds in patients with cancer, clinicians must consider the additive effects of bone damaging factors to which these patients are exposed and their premorbid fracture risk profile. Pharmacologic treatment should be offered as per cancer-specific guidelines when available, or per local general osteoporosis guidelines, in accordance with clinical judgment and patient preferences.

Thyroid-stimulating Hormone Suppressive Therapy and Osteoporosis: A Review and Meta-analysis

Background: Osteoporosis is a common morbid and mortal disease; thyroid-stimulating hormone (TSH) suppression is the state-of-the-art for postoperative differentiated thyroid carcinoma (DTC). However, its association with osteoporosis remains controversial. The current meta-analysis assessed the relationship between TSH suppressive therapy and osteoporosis among patients with DTC. Methods: We systematically searched PubMed, Cochrane Library, EBSCO, and the first 100 articles in Google Scholar for relevant articles published in English during the period from 2008 to November 2020. The keywords differentiated thyroid cancer, TSH suppression, osteoporosis, low bone mineral density, osteopenia; fracture risk, disturbed bone micro-architecture, bone loss, and trabecular bone were used. One hundred and eighty-four articles were retrieved; of them, fourteen were eligible and met the inclusion and exclusion criteria. The RevMan system was used for data analysis. Results: We included 36 cohorts from 15 studies, the studies showed higher osteoporosis and osteopenia among TSH-suppressed women, odd ratio, 2.64, 1.48– 4.68 and 2.23, 0.33–14.96, respectively. High heterogeneity was observed, I2 = 68% and 96%, respectively). The sub-analysis showed a lower bone mineral density among postmenopausal women at both femoral neck and lumbar spines, odds ratio, –0.02, –0.07 to 0.04, and –0.03, –0.06 to 0.01, I2 for heterogeneity, 69%, and 51% in contrast to men and premenopausal women who showed normal or higher bone density. Conclusion: TSH suppression for DTC was associated with osteoporosis and osteopenia among postmenopausal women but not premenopausal women or men. Studies focusing on trabecular bone scores are needed.

Regulation of bone mass in endocrine diseases including diabetes

Hormonal regulation plays a key role in determining bone mass in humans. Both skeletal growth and bone loss in health and disease is critically controlled by endocrine factors and low bone mass is a feature of both excess and deficiency of a broad range of hormones. This article explores the impact of diabetes and thyroid, parathyroid, sex steroid and growth hormone disorders on bone mass and fracture risk. Evidence for current management strategies is provided along with suggested practice points and gaps in knowledge for future research.