Low‐ and high‐dose radioiodine ablation for low‐/intermediate‐risk differentiated thyroid cancer in China: A large randomized clinical trial

Abstract Objective The baseline treatment of differentiated thyroid cancer (DTC) consists of thyroidectomy followed by postoperative risk-adapted radioiodine therapy (RAIT) when indicated. The choice of most appropriate RAI activities to administer with the aim to reach an efficient remnant ablation and reduce the risk of recurrence is yet an open issue and the detection of basal factors that may predict treatment response seems fundamental. The aim of this study was to investigate the potential role of Hashimoto thyroiditis (HT) in predicting 1-year and 5-year treatment response after RAIT and prognosis. Methods We retrospectively included 314 consecutive patients (174 low-risk and 140 intermediate-risk) who received thyroidectomy plus RAIT. One-year and 5-year disease status was evaluated according to 2015 ATA categories response based upon biochemical and structural findings. Results HT was reported histopathologically in 120 patients (38%). DTC patients with concomitant HT received a higher number of RAITs and cumulative RAI activities. Initial RAIT reached an excellent response in 63% after one year and 84% after 5 years. The rate of excellent response one year and 5-year after first RAIT was significantly lower in HT groups, compared to not HT (p < 0.001). Instead, HT did not have a prognostic role considering PFS and OS; while stimulate thyroglobulin (sTg) at ablation was significantly related to survival. Conclusions HT may affect the efficacy of RAIT in low to intermediate risk DTC, particularly reducing the successful rate of excellent response after RAIT. Instead, HT did not have a prognostic impact such as stimulated sTg.

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Efficacy of Low-Dose Radioiodine Ablation in Low- and Intermediate-Risk Differentiated Thyroid Cancer: A Retrospective Comparative Analysis

Journal of Clinical Medicine ◽

10.3390/jcm9020581 ◽

2020 ◽

Vol 9 (2) ◽

pp. 581

Author(s):

Ana María Gómez-Pérez ◽

Jorge García-Alemán ◽

María Molina-Vega ◽

Arantzazu Sebastián Ochoa ◽

Pilar Pérez García ◽

...

Keyword(s):

Thyroid Cancer ◽

Dose Group ◽

Low Dose ◽

Recurrence Risk ◽

High Dose ◽

Intermediate Risk ◽

Initial Recurrence ◽

Radioiodine Ablation ◽

Antithyroglobulin Antibodies ◽

The Moment

(1) Background—low-dose radioiodine ablation is an accepted strategy for the treatment of low- and intermediate-risk thyroid carcinomas, although there is no international consensus. The aim of this study is to describe the clinical experience with low-dose radioiodine ablation in patients with low- and intermediate-risk thyroid cancer compared to high-dose ablation. (2) Methods—174 patients with low- and intermediate-risk thyroid cancer, 90 treated with low-dose ablation and 84 treated with high-dose ablation, were included. The primary endpoint was response to treatment one year after ablation, defined by stimulated thyroglobulin, whole body scan and ultrasound imaging. (3) Results—an excellent response rate of 79.8% in the low-dose group and 85.7% in the high-dose group was observed (p = 0.049). Stimulated thyroglobulin at the moment of ablation (p = 0.032) and positive antithyroglobulin antibodies (p < 0.001) were independent predictive factors for nonexcellent response. Young age (p = 0.023), intermediate initial recurrence risk (p < 0.001) and low-dose ablation (p = 0.004) were independent predictive factors for recurrence. (4) Conclusion—low-dose ablation seemed to be less effective than high-dose ablation, especially in those patients with positive antithyroglobulin antibodies or higher stimulated thyroglobulin levels at the moment of ablation. Low dose was associated with higher recurrence rates, and lower age and intermediate initial recurrence risk were independent risk factors for recurrence in our sample.

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