Related Experiment Video
Updated: May 14, 2025
Computer-Aided Three-Dimensional Visualization in the Treatment of Locally Advanced Thyroid Cancer
Published on: June 9, 2023
Impact of Therapeutic Radioactive Iodine on the Recurrence of Papillary Thyroid Cancer With Extranodal Extension in
Hye In Kim1, Boram Kim2, Jiyeon Hyeon3
1Department of Medicine, Division of Endocrinology and Metabolism, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon.
Purpose:
Radioactive iodine therapy (RAI) ≥100 mCi (3.7 GBq) is commonly recommended for papillary thyroid cancer (PTC) patients with extranodal extension (ENE). However, no study has evaluated whether RAI ≥100 mCi is effective in reducing the recurrence of PTC with ENE.
Methods:
This retrospective cohort study enrolled 191 PTC patients with ENE who underwent total thyroidectomy and RAI. Recurrence according to RAI activity (<100 vs. ≥100 mCi) was compared before and after propensity score matching (PSM) (1:2) using Kaplan-Meier curves and Cox proportional hazards regression models. Subgroup analyses according to mass size (<4 and ≥4 cm), gender, blood vessel invasion, lymph node (LN) number (≤5 and >5), and stimulated Tg (sTg) level (<10 and ≥10 ng/mL) before and after PSM were performed.
Results:
During about 116 months, 5 (12.5%) and 19 (12.6%) before PSM, five (12.5%) and 3 (3.8%) after PSM recorded recurrence in <100 and ≥100 mCi groups, respectively. The impact of RAI ≥100 mCi on reducing recurrence was not significant before [log-rank P = 0.915, adjusted hazard ratio (HR) 0.49 (0.12-1.85); P = 0.294) and after PSM (log-rank P = 0.077). Subgroup analysis after PSM demonstrated the impact of RAI ≥100 mCi on lowering recurrence only in ENE patients with mass size ≥4 cm (log-rank P = 0.008), LN >5 (log-rank P = 0.007), and sTg ≥10 ng/mL (log-rank P = 0.039).
Conclusions:
In PTC patients with ENE, mass size ≥4 cm, LN >5, or sTg ≥10 ng/mL had a benefit from RAI ≥100 mCi compared with RAI <100 mCi.
