The success rate of I-131 ablation in differentiated thyroid cancer: comparison of uptake-related and fixed-dose strategies

• Published in: European journal of endocrinology Vol. 159; no. 3; pp. 301 - 307
• Main Authors: Verkooijen, Robbert B T, Verburg, Frederik A, van Isselt, Johannes W, Lips, Cornelis J M, Smit, Jan W, Stokkel, Marcel P M
• Format: Journal Article
• Language: English
• Published: England BioScientifica 01.09.2008
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Carcinoma, Papillary, Follicular - metabolism; Carcinoma, Papillary, Follicular - pathology; Carcinoma, Papillary, Follicular - radiotherapy; Carcinoma, Papillary, Follicular - surgery; Clinical Studies; Combined Modality Therapy; Disease Progression; Female; Follow-Up Studies; Humans; Iodine Radioisotopes - pharmacokinetics; Iodine Radioisotopes - therapeutic use; Male; Middle Aged; Radiotherapy Dosage; Radiotherapy, Adjuvant; Thyroid Neoplasms - metabolism; Thyroid Neoplasms - pathology; Thyroid Neoplasms - radiotherapy; Thyroid Neoplasms - surgery; Thyroidectomy; Treatment Outcome
• DOI: 10.1530/EJE-08-0062
• ISSN: 0804-4643

IntroductionThe aim of the study was to compare the success rate of an uptake-related ablation protocol in which the dose depends on an I-131 24-h neck uptake measurement and a fixed-dose ablation protocol in which the dose depends on tumour stage.MethodsAll differentiated thyroid carcinoma patients with M0 disease who had undergone (near-) total thyroidectomy followed by I-131 ablation were included. In the uptake-related ablation protocol, 1100 (uptake >10%), 1850 (uptake 5–10%) and 2800 MBq (uptake <5%) were used. In the fixed-dosage ablation strategy, 3700 (T1–3, N0 stage) and 5550 MBq (N1 and/or T4 stage) were applied. We used I-131 uptake on whole-body scintigraphy and thyroglobulin-off values to evaluate the ablation 6–12 months after treatment.ResultsIn the uptake-related ablation protocol, 60 out of 139 (43%) patients were successfully treated versus 111 out of 199 for the fixed-dose ablation protocol (56%) (P=0.022). The differences were not statistically significant for patients with T4 (P=0.581) and/or N1 (P=0.08) disease or for patients with T4N1 tumour stage (P=0.937).ConclusionThe fixed-dose I-131 ablation protocol is more effective in ablation of the thyroid remnant in differentiated thyroid carcinoma patients than an uptake-related ablation protocol. This difference is not observed in patients with a N1 and/or T4 tumour stage.