Change in pericardial fat volume in postmenopausal women with papillary thyroid cancer undergoing thyrotropin suppressive therapy.

[BACKGROUND] Despite TSH suppressive therapy improve the prognosis for the patient with differentiated thyroid cancer (DTC), there is an increasing concern regarding the potentially harmful effects of lifelong TSH suppression. Therefore, we aimed to examine the changes in body composition under TSH suppression in postmenopausal women with DTC.

[METHODS] The body composition was assessed by the volumes as following; fat tissues of the epicardium and abdominal visceral and subcutaneous areas; bilateral psoas muscle or thigh muscle. Each volumetric measurements were performed using computed tomography (CT) scans using baseline and follow-up fluorine-18 fluorodeoxyglucose positron emission tomography/CT (F-FDG PET/CT)s for 2-year follow up period in Pusan National University Hospital, South Korea.

[RESULTS] The 43 patients' median age was 50.0 years, and median body mass index (BMI) was 23.53 (interquartile range[IQR]: 22.19- 24.92) at the initial F-FDG PET/CT. The median follow-up period was 19.24 months (IQR: 17.24-21.79). No significant change in weight or BMI were observed during follow-up. Volumes of fat and muscles was not changed significantly except epicardial fat volume. The epicardial fat volume significantly increased during the follow-up period. The epicardial fat volumes were correlated with visceral fat volume, respectively, however, the changing ratio was only correlated with TSH suppression on multiple regression analysis.

[CONCLUSION] Both skeletal muscle and abdominal fat volumes did not change, whereas epicardial fat volume increased over less than 2 years of observation under TSH suppressive therapy. Further research is needed for the harmonization of benefits or losses with the optimal TSH concentration in postmenopausal women.