Serum TSH levels are associated with postoperative recurrence and lymph node metastasis of papillary thyroid carcinoma.

Objective: To explore the relationship between thyroid-stimulating hormone (TSH) levels in the serum and postoperative recurrence and lymph node metastasis (LNM) in papillary thyroid cancer (PTC) patients after surgery.

Methods: We selected 272 patients diagnosed with PTC from June 2011 to July 2014. The clinical and pathological data of 272 PTC patients were collected at the First Affiliated Hospital of Wenzhou Medical University and analysed retrospectively. All PTC patients were tested for the BRAF gene mutation before surgery by fine-needle aspiration (FNA) cytology, and TSH levels in the serum were determined one month after surgery. The optimal cut-off value of thyroid-stimulating hormone (TSH) for predicting the recurrence or metastasis of PTC after surgery was determined by the establishment of a receiver operating characteristic (ROC) curve. Kaplan-Meier and Cox regression analyses were used to evaluate the correlation between the optimal cut-off value of TSH and disease-free survival rate and prognosis.

Results: Of 272 patients, only 182 (73 BRAF, 109 BRAF) met the final study criteria. Among them, 60 cases had recurrence or metastasis, and 122 cases were controls. The optimal cut-off value of TSH for the prediction of recurrence or metastasis of PTC after surgery was 2.615 mlU/L. In our study, a high TSH level (> 2.615 mlU/L) was correlated with the BRAF mutation, multifocality, lymph node metastasis, recurrence, and metastasis. In all 182 patients, those with high TSH levels had worse disease-free survival. This result was more obvious in the 73 BRAF patients. The univariate analysis showed that lymph node metastasis, multifocality, lymph node dissection, tumour size, sex, BRAF mutation, and a high postoperative TSH level were all significantly correlated with recurrence or metastasis in PTC patients (all ). In addition, the Cox multivariate analysis showed that lymph node metastasis, BRAF mutation, and high postoperative TSH levels were independent risk factors for PTC recurrence or metastasis (all ).

Conclusion: PTC patients with high TSH levels (> 2.615 mlU/L) have worse disease-free survival, which is more obvious in the BRAF population.