Ken Watanabe1, Mayuki Uchiyama2, Kunihiko Fukuda2. 1. Department of Radiology, The Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo, 105-8461, Japan. kwata_1015@jikei.ac.jp. 2. Department of Radiology, The Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo, 105-8461, Japan.
Abstract
PURPOSE: This article examines the outcome of radioactive iodine ablation therapy for thyroid cancer in high-risk patients and investigates background factors influencing ablation failure. MATERIALS AND METHODS: We included 91 patients in this retrospective analysis and evaluated the ablation success rate. Successful ablation was defined as the absence of visible iodine-131 (I-131) accumulation in the thyroid bed after whole-body scans and thyroglobulin levels <2 ng/ml in a TSH-stimulated state after ablation. We extracted data on patients' age, sex, I-131 dose, pathology, resection stump findings, tumor T category and thyroglobulin levels, which could affect ablation outcome. RESULTS: Successful ablation was achieved in only 14 patients (15.4%). Pre-ablation serum thyroglobulin levels were significantly higher in the ablation failure group than in the success group (P < 0.001), while no significant differences were found for other factors between the groups. Furthermore, thyroglobulin levels >10 ng/ml were significantly related to ablation failure after multivariate analysis (odds ratio 27.2; 95% confidence interval 2.469-299.7; P = 0.007). CONCLUSION: The ablation success rate was very low because of high thyroglobulin levels, even with high-dose I-131. High-risk patients, especially those with high thyroglobulin levels (>10 ng/ml), are unlikely to reach levels low enough to meet successful ablation criteria.
PURPOSE: This article examines the outcome of radioactive iodine ablation therapy for thyroid cancer in high-risk patients and investigates background factors influencing ablation failure. MATERIALS AND METHODS: We included 91 patients in this retrospective analysis and evaluated the ablation success rate. Successful ablation was defined as the absence of visible iodine-131 (I-131) accumulation in the thyroid bed after whole-body scans and thyroglobulin levels <2 ng/ml in a TSH-stimulated state after ablation. We extracted data on patients' age, sex, I-131 dose, pathology, resection stump findings, tumor T category and thyroglobulin levels, which could affect ablation outcome. RESULTS: Successful ablation was achieved in only 14 patients (15.4%). Pre-ablation serum thyroglobulin levels were significantly higher in the ablation failure group than in the success group (P < 0.001), while no significant differences were found for other factors between the groups. Furthermore, thyroglobulin levels >10 ng/ml were significantly related to ablation failure after multivariate analysis (odds ratio 27.2; 95% confidence interval 2.469-299.7; P = 0.007). CONCLUSION: The ablation success rate was very low because of high thyroglobulin levels, even with high-dose I-131. High-risk patients, especially those with high thyroglobulin levels (>10 ng/ml), are unlikely to reach levels low enough to meet successful ablation criteria.
Entities:
Keywords:
Iodine-131; Radioiodine therapy; Remnant ablation; Thyroid cancer
Authors: Michael Tamilia; Nora Al-Kahtani; Louise Rochon; Michael P Hier; Richard J Payne; Christina A Holcroft; Martin J Black Journal: Nucl Med Commun Date: 2011-03 Impact factor: 1.690
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