Efficacy and safety of anlotinib combined with I seed implantation for iodine-refractory thyroid cancer.

BACKGROUND AND OBJECTIVE

Radioiodine-refractory differentiated thyroid cancer (RAIR-DTC) remains challenging to treat due to a lack of effective therapies. This study aimed to evaluate the efficacy and safety of combining anlotinib with iodine-125 (I) seed implantation in patients with RAIR-DTC.

METHODS AND MATERIALS

We retrospectively compared three treatment groups in 52 patients with advanced RAIR-DTC: anlotinib monotherapy (Group A, = 14), I seed brachytherapy monotherapy (Group B, = 25), and combined therapy (Group C, = 13). Clinical outcomes including local progression-free survival (LPFS), overall survival (OS), tumor response, serum thyroglobulin (Tg) levels, and adverse events were analyzed.

RESULTS

As of February 2025, the combination therapy group achieved a longer median LPFS (42.2 months) than either monotherapy group (18.6-18.7 months; = 0.023) and a higher objective response rate at 6 months (77% vs. 21-32% with monotherapies; < 0.05). Tumor volumes in all groups decreased after treatment, with the greatest reduction within 6 months in the combination group ( < 0.001). By 12 months, response differences between groups narrowed, and median OS was similar across groups (~22-43 months, = 0.425). Serum Tg levels declined significantly from baseline in all groups. No major procedural complications occurred, and treatment-related adverse reactions were mostly mild (Grade 1-2) and comparable among groups.

CONCLUSION

Combining I seed brachytherapy with anlotinib demonstrated superior short-term tumor control and prolonged local disease remission in RAIR-DTC, without increasing toxicity. This combination may offer a promising therapeutic option for RAIR-DTC, pending further validation in larger studies.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov, identifier NCT06362772.