Session: SUN 459-496-Thyroid Neoplasia & Case Reports
Poster Board SUN-477
Subjects & Methods : The retrospective study was designed to compare the efficacy of rhTSH with THW before ablation in low-dose RAI (30 mCi) ablation as well as high-dose (100 mCi) ablation. A total of 576 patients [ papillary thyroid carcinoma 564 (98%); rhTSH 192 vs. THW 384] were enrolled, who had TNM stage, T1 to T3, N0 to N1, and M0. Patients underwent THW were selected twice in number as age, gender, T-stage and N-stage matched patients. The successful ablation was defined as stimulated serum thyroglobulin (Tg) less than 1 to 2 ng/mL with undetectable serum anti-Tg antibody or absence of significant visible uptake above background activity in the neck on diagnostic whole-body scan (DxWBS) at 6 to 12 months after first RAI ablation. The successful ablation rates were estimated in each group under the five criteria: Criteria 1 (negative DxWBS), 2 (Tg <2 ng/mL), 3 (Tg <2 ng/mL & negative DxWBS), 4 (Tg <1 ng/mL), and 5 (Tg <1 ng/mL & negative DxWBS). We allowed maximum differences within 10% between rhTSH and THW. All 95% confidence intervals for the differences were within -10%, indicating noninferiority.
Results : When only negative DxWBS was chosen as a successful criterion in patients administered with low-dose RAI, successful ablation rates were 80.5% in patients with rhTSH compared to 79.9% with THW (p=0.91). When only stimulated serum Tg level less than 2 ng/mL was considered as a successful criterion, they were 95.4% in patients with rhTSH compared to 92.5% with THW (p=0.40). When both of stimulated serum Tg level (<2 ng/mL) and negative DxWBS were selected as successful criteria, they were reduced to 79.3% in patients with rhTSH compared to 75.9% with THW (p=0.53). When only stimulated serum Tg level less than 1 ng/mL was considered as a successful criterion, they were 89.6% in patients with rhTSH compared to 86.2% with THW (p=0.42). When both of stimulated serum Tg level (<1 ng/mL) and negative DxWBS were selected as successful criteria, they were reduced to 77.0% in patients with rhTSH compared to 71.3% with THW (p=0.32). Therefore, low-dose RAI ablation in patients with rhTSH was as effective as THW, using any criteria of successful ablation.Similar results were found in the efficacy of high-dose RAI ablation in patients with rhTSH compared to THW, using any criteria of successful ablation.
Conclusion : Low-dose RAI ablation with rhTSH was as effective as THW before ablation in Korean patients with differentiated thyroid carcinoma.
Nothing to Disclose: NKK, JYJ, YYC, SYS, HJK, HKT, YJC, SWK, JHC
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