On-demand l -thyroxine replacement therapy in post-lobectomy papillary thyroid cancer: a prospective nonrandomized controlled study.

BACKGROUND

The necessity of thyrotropin (TSH) suppression therapy for papillary thyroid cancer (PTC) after lobectomy has been challenged. This study aims to evaluate on-demand l -thyroxine replacement therapy for post-lobectomy PTC.

METHODS

This prospective study cohort included adult patients with low- to intermediate-risk PTC, who underwent lobectomy (2021-2023). l -Thyroxine supplementation was given after surgery only if serum TSH exceeded the upper limit of the reference range (>5.91 mU/L). Retrospective controls were selected from the institute database (2000-2014) after being matched with prospective patients and treated according to the guideline (TSH, 0.5-2 mU/L). The primary endpoint was prognosis, including structural recurrence and biochemical response. The secondary endpoint was the euthyroidism rate without thyroxine. The Kaplan-Meier curve was used to estimate recurrence-free survival (RFS) and euthyroidism rates, and compared using the log-rank test.

RESULTS

Among 381 patients who were enrolled in the present study (median age 39 years, 70.6% female), no new cases were detected requiring l -thyroxine for elevated TSH at greater than year post surgery. In the prognostic evaluation, 333 cases were included, with a mean follow-up of 17 months, and 72.3% never underwent l -thyroxine supplementation. Comparison with the historical control group was conducted in 204 pairs of cases. No significant difference was observed in either 2-year RFS (test group vs. control group, 99.4% vs. 98.5%, P = 0.917) or biochemical responses among patients with negative thyroglobulin (Tg) antibody (rate of patients with increasing Tg, 21.6% vs. 21.6%, P> 0.05).

CONCLUSIONS

On-demand l -thyroxine replacement therapy benefit three-fourths of post-lobectomy low- to intermediate-risk PTC patients avoid l -thyroxine supplementation, while preserving equivalent short-term treatment response and RFS.