TSH Cut-Offs and Recurrence Risk in Differentiated Thyroid Carcinomas: A Systematic Review and Meta-Analysis

Abstract

Purpose: This meta-analysis aimed to investigate the risk of recurrence in patients with differentiated thyroid cancer (DTC), stratified by the American Thyroid Association (ATA) risk of recurrence, according to variable thyrotropin (TSH) cut-offs (0.1, 0.5, and 2.0 mIU/L).

Methods: We searched Ovid-Medline, EMBASE, and Cochrane databases for studies reporting the recurrence rate of DTCs based on TSH cut-offs through March 2024. The search terms used included 'thyroid neoplasm' OR 'cancer,' 'TSH' OR 'thyroid stimulating hormone,' 'suppress' OR 'supplementation,' and 'thyroidectomy'.

Results: Two randomized controlled trials and seven observational studies, including 5,320 patients, were analyzed, with an overall recurrence rate of 18%. The pooled recurrence risk for DTCs at each TSH cut-off (0.1, 0.5, and 2.0 mIU/L) was not significant. In the subgroup analysis, the pooled hazard ratios [HRs] stratified by the ATA risk of recurrence (low- and high-risk DTCs) did not differ according to TSH levels. However, the risks of recurrence increased at serum TSH ≥0.1 mIU/L (HR 2.27, 95% CI 1.29-3.99) and TSH ≥2.0 mIU/L (HR 1.36, 95% CI 1.001-1.84) in a leave-one-out meta-analysis after removing the study that has significantly influenced the analysis. Patients with distant metastases had a higher risk of recurrence (HR 3.3, 95% CI 1.53-7.10) when maintaining TSH ≥0.1 mIU/L.

Conclusion: The degree of TSH suppression did not affect the overall risk of DTC recurrence. However, TSH suppression may be beneficial in reducing the recurrence risk in high-risk patients with distant metastases.

Keywords: TSH; recurrence; suppression; thyroid cancer.