Risk Factors for Predicting Osteoporosis in Patients Who Receive Thyrotropin Suppressive Levothyroxine Treatment for Differentiated Thyroid Carcinoma

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.

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.