A preliminary study to evaluate efficacy and safety of Lugol’s solution following radioiodine for remnant ablation in differentiated thyroid cancer

TL;DR

This study tested if adding Lugol’s solution after radioiodine therapy improves thyroid cancer treatment effectiveness and reduces long-term side effects.

Contribution

The study is the first to show that Lugol’s solution may reduce long-term adverse events after radioiodine therapy in thyroid cancer patients.

Findings

Lugol’s solution did not improve ablation success rates but showed a trend toward better outcomes with stricter criteria.

The test group had significantly fewer long-term adverse events compared to the control group.

Short-term adverse events were slightly higher in the test group but not statistically significant.

Abstract

This randomized controlled trial aimed to determine if Lugol’s solution following radioactive iodine (RAI) therapy enhances the efficacy of ablation and mitigates radiation-induced toxicity in patients with differentiated thyroid cancer.

In this prospective study, 97 patients were enrolled and randomized to control group (RAI) and test group (RAI + Lugol’s solution). The primary endpoint was the rate of successful ablation. The secondary endpoint was short-term (d3 and d10) and long-term (6- to 9-month after RAI therapy) adverse events (AEs).

The rate of negative DxWBS was similar between control and test group (93.3% vs. 91.2%, p = 0.748). At the 6- to 9-month follow-up, while the successful ablation rate (sTg <1 ng/mL) was numerically higher in the test group compared to the controls (82.8% vs. 66.7%, p=0.131), applying a stricter stimulated thyroglobulin (sTg) cutoff (<0.2 ng/mL) revealed a statistically significant advantage for the test group (65.7% vs. 40.0%, p = 0.041). Uni- and multi-variate analysis showed Lugol’s Solution administration significantly correlated with lower level of sTg at the 6- to 9-month follow-up. The two groups exhibited comparable short-term AEs rates (46% vs. 34%, p = 0.230) and profiles. The most common AEs included neck swelling, pain, loss of appetite and dry mouth. However, the control group reported 2 cases of long-term AEs, whereas none were observed in the test cohort.

In this preliminary study, the addition of Lugol’s Solution following RAI showed non-inferior ablation efficacy with a numerically lower incidence of long-term AEs, despite numerically higher short-term AE rates.

It was registered at Chinese Clinical Trial Registry with identifier ChiCTR1900027705 at November 24th, 2019.

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