Low BMI and low TSH value as risk factors related to lower bone mineral density in postmenospausal women under levothyroxine therapy for differentiated thyroid carcinoma

Application and prospect of trabecular bone score in differentiated thyroid cancer patients receiving thyrotropin suppression therapy

Thyroid-stimulating hormone (TSH) suppression therapy is one of the common treatments for most patients with differentiated thyroid cancer (DTC). Unfortunately, its detrimental effects on bone health are receiving increasing attention. It may increase the risk of osteoporosis and osteoporotic fractures. The trabecular bone score (TBS) is a relatively new gray-scale texture measurement parameter that reflects bone microarchitecture and bone strength and has been shown to independently predict fracture risk. We reviewed for the first time the scientific literature on the use of TBS in DTC patients on TSH suppression therapy and aim to analyze and compare the utility of TBS with bone mass strength (BMD) in the management of skeletal health and prediction of fracture risk. We screened a total of seven relevant publications, four of which were for postmenopausal female patients and three for all female patients. Overall, postmenopausal female patients with DTC had lower TBS and a significant reduction in TBS after receiving TSH suppression therapy, but their BMD did not appear to change significantly. In addition, TBS was also found to be an independent predictor of osteoporotic fracture risk in postmenopausal women with DTC receiving TSH suppression therapy. However, due to limitations in the number of studies and study populations, this evidence is not sufficient to fully demonstrate the adverse effects of TSH suppression therapy on patients' TBS or BMD and the efficacy of TBS, and subsequent larger and more case-cohort studies are needed to further investigate the relationship and application of TBS to TSH suppression therapy in terms of skeletal health impairment and fracture risk in DTC patients.

Measurements of Bone Health after Thyroid-Stimulating Suppression Therapy in Postmenopausal Women with Differentiated Thyroid Carcinoma: Bone Mineral Density versus the Trabecular Bone Score

Background: Thyroid-stimulating hormone (TSH) suppression therapy is an important treatment modality for differentiated thyroid carcinoma (DTC), but it increases fracture risk. The aim of this study was to evaluate changes in bone mineral density (BMD) and trabecular bone score (TBS) in postmenopausal DTC patients receiving TSH suppression therapy. Methods: A total of 410 postmenopausal DTC patients who underwent thyroidectomy and had at least two dual-energy X-ray absorptiometry measurements, including a preoperative measurement, were included. Patients who had osteoporosis medication for more than 1 year were classified as ‘patients with osteoporosis’. Results: In patients without osteoporosis, the change in %BMD was similar between TSH suppression (−) and (+) groups, while the decrease in %TBS was significantly greater in the TSH suppression (+) group than that of the TSH suppression (−) group. The relative risk of vertebral fracture was decreased by TBS changes but not by BMD changes. In patients with osteoporosis, both BMD and TBS showed significant increases in the TSH suppression (−) group but not in TSH suppression (+) group. At year 4, TBS was significantly lower in the TSH suppression (+) group than that in the TSH suppression (−) group, while BMD showed no difference between groups. Conclusions: TBS may better reflect bone health than BMD in postmenopausal DTC patients with TSH suppression therapy.

Skeletal health in patients with differentiated thyroid carcinoma

Osteoporosis and fractures are important comorbidities in patients with differentiated thyroid cancer (DTC), with potential negative impact on quality of life and survival. The main determinant of skeletal fragility in DTC is the thyrotropin (TSH)-suppressive therapy, which is commonly recommended to prevent disease's recurrence, especially in patients with structural incomplete response after thyroid surgery and radio-iodine therapy. TSH-suppressive therapy can stimulate bone resorption with consequent bone loss, deterioration of bone microstructure and high risk of fragility fractures. The skeletal effects of TSH-suppressive therapy may be amplified when thyroid cancer cells localize to the skeleton inducing alterations in bone remodelling, impairment of bone structure and further increase in risk of fractures. The management of skeletal fragility in DTC may be challenging, since prediction of fractures is a matter of uncertainty and data on effectiveness and safety of bone-active agents in this clinical setting are still scanty. This review deals with pathophysiological, clinical and therapeutic aspects of skeletal fragility of patients with DTC.

Effects of Thyrotropin Suppression on Bone Health in Menopausal Women with Total Thyroidectomy

Background

This study examined the change in the trabecular bone score (TBS), areal bone mineral density (aBMD), and osteoporosis in postmenopausal women who underwent thyrotropin (TSH)-suppressive therapy for treating papillary thyroid cancer after a total thyroidectomy procedure.

Methods

We evaluated 36 postmenopausal women who received a total thyroidectomy for papillary thyroid cancer and were undergoing TSH suppressive therapy with levothyroxine. Postmenopausal women (n=94) matched for age and body mass index were recruited as healthy controls. The aBMD and TBS of the lumbar spine were compared between dual energy X-ray absorptiometry (DXA) at baseline and at follow-up after an average of 4.92 years.

Results

There was no significant difference in the rate of diagnoses of osteoporosis, osteopenia, or normal bone status between the 2 groups during the baseline DXA evaluation. However, the TBS was significantly lower whereas aBMD did not show significant difference at the time of baseline DXA measurement (1st DXA, 1.343±0.098 vs. 1.372±0.06317, P<0.001; 2nd DXA, 1.342±0.095 vs. 1.370±0.062, P<0.001). The TBS and aBMD did not differ significantly between the initial and follow-up DXA images in both groups of TSH suppressive patients and controls.

Conclusions

The average value of TBS and aBMD did not significantly change during the follow-up period. The TSH suppressive therapy was revealed as not a significant factor for the progressive deterioration of bone status during long term follow-up.

Evaluation of Bone Mineral Density Using DXA and cQCT in Postmenopausal Patients Under Thyrotropin Suppressive Therapy

PURPOSE

This study aimed to examine the discrepancy in osteoporosis diagnoses between central quantitative computed tomography (cQCT) and dual-energy X-ray absorptiometry (DXA) and evaluated correlations among volumetric bone mineral density (vBMD), areal bone mineral density (aBMD), and trabecular bone score(TBS) in postmenopausal women who were undergoing TSH suppressive therapy.

METHODS

We enrolled a total of 81 postmenopausal patients [median age: 58 years; interquartile range (IQR): 57 to 60 years] receiving TSH suppressive therapy with levothyroxine after undergoing total thyroidectomy for papillary thyroid cancer. Patients were diagnosed by their bone mineral density (BMD) T-score and categorized according to a vBMD threshold of 120 mg/cm3 for osteopenia and a threshold of 80 mg/cm3 for osteoporosis.

RESULTS

When DXA and cQCT were compared, the BMD evaluation results differed in 76% of patients (n = 62; P < 0.001), and the detection rate of osteoporosis was 30.9% for cQCT and 21.0% for DXA. Sixty-two patients had discordant results; in 46 of these patients (74%) whose DXA T-scores were normal, the diagnosis shifted to osteopenia (n = 35) and osteoporosis (n = 11) according to the vBMD on cQCT (P < 0.001), and their vBMD values were significantly correlated with TBS (r = 0.293; P = 0.008). However, aBMD was not significantly correlated with TBS (r = 0.080; P = 0.480). TBS was significantly lower in patients with osteopenia (median: 1.35; IQR: 1.18 to 1.47) and osteoporosis (median: 1.28; IQR: 1.07 to 1.47) than in those with a normal BMD value (median: 1.37; IQR: 1.25 to 1.49; P = 0.041) on cQCT. There was no significant difference in TBS according to DXA BMD status (P = 0.200).

CONCLUSIONS

DXA and cQCT yielded inconsistent results, and detection of osteopenia and osteoporosis was higher using cQCT. TBS showed a more significant correlation with vBMD than with aBMD.

Effects of thyrotropin suppression on lumbar bone mineral density in postmenopausal women with differentiated thyroid carcinoma

Purpose

The aim of this study was to evaluate the effect of postoperative thyroid-stimulating hormone suppression (TSHS) on bone mineral density (BMD) in Chinese postmenopausal women with differentiated thyroid carcinoma (DTC).

Patients and methods

A total of 225 postmenopausal women with DTC who had received TSHS were included in the study. Postmenopausal women with postoperative DTC undergoing thyroid residual ablation or metastasis treatment between 2009 and 2015 were enrolled and followed up for 2 years. They were divided into two groups: TSHS group (median thyroid-stimulating hormone [TSH] <0.3 μIU/mL) and postmenopausal control group (median TSH >0.3 μIU/mL). Lumbar 1–4 BMD levels were measured by a dual-energy X-ray absorptiometry (DXA) at baseline and 6, 12 and 24 months. All patients had calcium and vitamin D supplementation. The diagnosis of osteopenia (−1 SD > T >−2.5 SD) and osteoporosis (T <−2.5 SD) was made according to WHO guidelines.

Results

Thyroid cancers included 211 papillary carcinomas and 14 follicular carcinomas. One hundred and fifty-four patients were in the TSHS group, and 71 patients were in the non-suppressed TSH group (postmenopausal controls). No significant differences were found in the BMD of the lumbar spine between baseline and after 6, 12 and 24 months, pre and post treatment in TSHS and non-suppressed TSH patients. Compared with pre-TSHS, there was a reduction in the BMD of 1.9% in the lumbar spine at the 2-year follow-up. Significant difference in the number of osteopenia and osteoporosis patients at 24 months (χ²=2.88, P=0.004) was found between the TSHS (103/152) and postmenopausal control (32/68) groups. TSHS is not a significant risk of bone loss, but it is the incidence of osteopenia in postmenopausal women with DTC.

Conclusion

Our 2-year follow-up data indicated that TSHS had little effect on BMD in postmenopausal women with DTC. Large population with at least 5-year follow-up should be further investigated. BMD in postmenopausal women with DTC should be followed up regularly.

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.

Effect of Thyrotropin Suppression Therapy on Bone in Thyroid Cancer Patients

BACKGROUND

The thyroid cancer incidence is rising. Despite current guidelines, controversy exists regarding the degree and duration of thyrotropin suppression therapy. Also, its potential skeletal effects remain a concern to physicians caring for thyroid cancer patients. We conducted a review of published data to evaluate existing studies focusing on the skeletal effects of thyrotropin suppression therapy in thyroid cancer patients.

MATERIALS AND METHODS

A systematic search of the PubMed, Ovid/Medline, and Cochrane Central Register of Controlled Trials databases was conducted. The retained studies were evaluated for methodological quality, and the study populations were categorized into premenopausal women, postmenopausal women, and men.

RESULTS

Twenty-five pertinent studies were included. Seven studies were longitudinal and 18 were cross-sectional. Of the 25 included studies, 13 were assigned an excellent methodological quality score. Three of 5 longitudinal studies and 3 of 13 cross-sectional studies reported decreased bone mineral density (BMD) in premenopausal women; 2 of 4 longitudinal studies and 5 of 13 cross-sectional studies reported decreased BMD in postmenopausal women. The remaining studies showed no effect on BMD. The only longitudinal study of men showed bone mass loss; however, cross-sectional studies of men did not demonstrate a similar effect.

CONCLUSION

Studies to date have yielded conflicting results on the skeletal effects of thyrotropin suppression therapy and a knowledge gap remains, especially for older adults and men. Existing data should be cautiously interpreted because of the variable quality and heterogeneity. Identifying groups at risk of adverse effects from thyrotropin suppression therapy will be instrumental to providing focused and tailored thyroid cancer treatment.

IMPLICATIONS FOR PRACTICE

The standard treatment for thyroid cancer includes total thyroidectomy with or without radioactive iodine ablation, often followed by thyrotropin suppression therapy. Despite current guidelines, controversy exists regarding the degree and duration of thyrotropin suppression therapy, and discordant results have been reported on its adverse effects on bone. The present review provides physicians with existing data on the skeletal effects of thyrotropin suppression therapy, highlighting the need for further research to identify the groups at risk of adverse skeletal effects. This knowledge will aid in developing tailored thyroid cancer treatment.