99Tc-MDP in Postmenopausal Women With Differentiated Thyroid Cancer and Osteoporosis

Postmenopausal women with differentiated thyroid cancer (DTC) taking suppressive doses of levothyroxine (L-T4) are thought to have accelerated bone loss and increased risk of osteoporosis. Therefore, the investigators try to investigate the effects of 99Tc-MDP,alendronate sodium in postmenopausal women with DTC under TSH suppression and osteoporosis.

Differentiated thyroid cancer (DTC) has become one of the most common endocrine malignancies. According to American Thyroid Association (ATA) and Chinese Thyroid Association (CTA), most of DTC patients undergo total or near total thyroidectomy, radioiodine ablation and TSH (thyroid stimulating hormone) suppression. Osteoporosis (OS) and fractures are important comorbidities in patients with DTC, with potential negative impact on quality of life (QOL) and survival. The main determinant of skeletal fragility in DTC is the TSH suppression. Postmenopausal women with DTC under TSH suppression therapy are more vulnerable to OS. Technetium-99 methylene diphosphonate (99Tc-MDP) is a decay product of 99mTc-MDP (used for bone scintigraphy) and a novel bisphosphonates, which has been used in China for diseases like rheumatoid arthritis (RA), ankylosing spondylitis (AS) and osteochondral lesions of the talus, etc. However, as a member of bisphosphates, little attention has been paid to its anti-OS effect for DTC under TSH suppression.