To compare disease-specific survival and recurrence-free survival (RFS) after successful I-131 ablation in patients with differentiated thyroid carcinoma (DTC) between those defined before ablation... Show moreTo compare disease-specific survival and recurrence-free survival (RFS) after successful I-131 ablation in patients with differentiated thyroid carcinoma (DTC) between those defined before ablation as low-risk and those defined as high-risk according to the European Thyroid Association 2006 consensus statement. Retrospective data from three university hospitals were pooled. Of 2009 consecutive patients receiving ablation, 509 were identified as successfully ablated based on both undetectable stimulated serum thyroglobulin in the absence of antithyroglobulin antibodies and a negative diagnostic whole-body scan in a follow-up examination conducted 8.1 +/- 4.6 months after ablation. Of these 509 patients, 169 were defined as high-risk. After a mean follow-up of 81 +/- 64 months (range 4-306 months), only three patients had died of DTC, rendering assessment of disease-specific survival differences impossible. Of the 509 patients, 12 (2.4%) developed a recurrence a mean 35 months (range 12-59 months) after ablation. RFS for the duration of follow-up was 96.6% according to the Kaplan-Meier method. RFS did not differ between high-risk and low-risk patients (p=0.68). RFS differed slightly but significantly between those with papillary and those with follicular thyroid carcinoma (p=0.03) and between those aged a parts per thousand currency sign45 years those aged > 45 years at diagnosis (p=0.018). After (near) total thyroidectomy and successful I-131 ablation, RFS does not differ between patients classified as high-risk and those classified as low-risk based on TNM stage at diagnosis. Consequently, the follow-up protocol should be determined on the basis of the result of initial treatment rather than on the initial tumour classification. Show less
The therapy of choice in patients suffering from differentiated thyroid cancer (DTC), subdivided into papillary and follicular thyroid carcinoma, is (near-)total thyroidectomy. This is routinely... Show moreThe therapy of choice in patients suffering from differentiated thyroid cancer (DTC), subdivided into papillary and follicular thyroid carcinoma, is (near-)total thyroidectomy. This is routinely followed by the administration of radioiodine (RaI)-131 (131I) to destroy any remaining benign or malignant thyroid tissue, so-called ablation. This thesis has addressed some important clinical questions, related to the application of conventional (131I) and experimental therapies with radionuclides in DTC. Iodine-131 has been used for many years to ablate thyroid remnants following thyroid surgery, but a single optimal activity has not yet been established. Two protocols are commonly used in the Netherlands: the uptake-related ablation strategy in which relatively low activities of 131I are used and the fixed-dose or tumor-related ablation strategy in which higher ablation activities are used. The main aim of this thesis was to study the short-term and long-term outcome parameters in DTC according to the uptake-related ablation protocol and to compare the success rates of both ablation strategies. Furthermore, we investigated whether there was a relation between ablation failure and pre-ablation 24-hour uptake measurement of 131I (by the so-called stunning effect). By assessing the prevalence of second primary tumors in patients treated for thyroid cancer we wanted to confirm that 131I can be used safely regarding long-term effects. Finally, this thesis focused on 111In-DTPA-octreotide scintigraphy and therapy as an alternative tool in progressive radioiodine non-responsive thyroid cancer. Show less
