Factors influencing postoperative thyroid-stimulating hormone suppression therapy in low-risk papillary thyroid cancer after lobectomy.

BACKGROUND: Thyroid-stimulating hormone (TSH) suppression therapy remains an important treatment option for patients with low-risk differentiated thyroid cancer (DTC). This study aimed to analyze the potential influencing factors affecting TSH suppression outcomes in patients with postoperative low-risk papillary thyroid cancer (PTC). METHODS: A total of 223 low-risk PTC patients were enrolled in this single-center cross-sectional study between September 2024 and February 2025. Based on the TSH level measured at 4-6 months post-lobectomy, the patients were divided into three groups: an excessive TSH suppression group (TSH <0.5 mU/L), optimal TSH suppression group (TSH 0.5-2.0 mU/L), and insufficient TSH suppression group (TSH >2.0 mU/L). The clinicopathological data of the patients, including demographic, clinical laboratory, pathological, and lifestyle characteristics, were analyzed to investigate the factors influencing TSH suppression therapy. RESULTS: There were no statistically significant differences in age, marital status, preoperative free triiodothyronine (FT3), free thyroxine (FT4), thyroglobulin antibody (TG-Ab), thyroid peroxidase antibody (TPO-Ab), thyroglobulin (Tg) level, longest tumor diameter, lesion site, central lymph node metastasis, Hashimoto's thyroiditis, BRAF V600E mutation, levothyroxine intake habits, dietary habits, or sleep habits among the three groups (all P>0.05). The distributions of sex, body mass index (BMI), comorbidities, preoperative TSH levels, multifocal lesions, levothyroxine dose, physical activity, and sedentary time differed significantly among the three groups (all P<0.05). Multivariate logistic regression analyses demonstrated that excessive TSH suppression was significantly associated with female sex, a higher levothyroxine dose (≥1.6 µg/kg/day), lower preoperative TSH levels, lower physical activity, and higher sedentary time. Conversely, insufficient TSH suppression was independently associated with higher BMI and lower levothyroxine dose (<1.6 µg/kg/day). CONCLUSIONS: A complex interplay exists among demographic, clinical, and lifestyle factors in postoperative TSH management. Prospective studies with objective lifestyle measurements are needed to confirm these associations before clinical implementation.