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The purpose of this prospective study was to determine the diagnostic impact and influence on patient treatment of posttherapeutic 131I SPECT-CT when the findings on planar posttherapeutic whole-body scintigraphy (ptWBS) were inconclusive. A total of 53 SPECT-CT scans were performed in 41 patients with thyroid cancer after high-dose 131I therapy (2.944 to 7.526 GBq 131I) because of diagnostic uncertainty on ptWBS. Physiological uptake in the salivary glands, gastric mucosa, gut, nasal mucosa, urinary tract and liver were considered to be normal. Any other foci of increased 131I uptake, except iodine uptake clearly located in the thyroid bed, were considered to be abnormal. The data were evaluated on a lesion and a patient basis. Regarding neck lesions, SPECT-CT provided a diagnostic impact in 26/90 lesions (28.9%) and confirmed the diagnosis in 64/90 lesions (71.1%). On a patient basis, SPECT-CT changed N status in 12/33 patients (36.4%), provided a diagnostic impact in 21/33 patients (63.6%) and led to a treatment change in 8/33 patients (24.2%). Regarding lesions distant from the neck, SPECT-CT confirmed the diagnosis in 62/71 lesions (87.3%) and had a diagnostic impact in 9/71 lesions (12.7%). On a patient basis, SPECT-CT changed M status in 4/19 patients (21.1%), had a diagnostic impact in 14/19 patients (73.7%) and led to a treatment change in 2/19 patients (10.5%). Considering all patients, SPECT-CT led to a treatment change in 10/41 patients (24.4%). Integrated SPECT-CT is a useful tool, especially in cases of diagnostic uncertainty and helps to individualize patient management. [ABSTRACT FROM AUTHOR]

Purpose: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a well-established method in the follow-up of patients with differentiated thyroid carcinoma (DTC), elevated thyroglobulin (Tg) and negative 131I scans. This retrospective clinical study was designed to evaluate the impact of computed tomography (CT) and that of FDG-PET in combined FDG-PET/CT examinations on the restaging of DTC patients., Methods: Forty-seven FDG-PET/CT scans of 33 patients with a history of DTC, elevated Tg levels and negative 131I uptake or additionally suspected 131I-negative lesions were studied. PET and CT images were analysed independently by an experienced nuclear medicine specialist and a radiologist. Afterwards a final consensus interpretation, the gold standard in our department, was provided for the fused PET/CT images and, if available, for supplementary investigations., Results: Thirty-five investigations (74%) revealed pathological FDG-PET/CT findings. In summary, 25 local recurrences, 62 lymph node metastases and 122 organ metastases (41 lung, 60 bone, 21 other organs) were diagnosed. In 36 out of 47 examinations (77%), the original PET diagnoses were modified in the final consensus interpretation owing to the CT assessments. In 8 of the 35 pathological FDG-PET/CT examinations (23%), the final consensus interpretation of the PET/CT images led to an alteration in the treatment plan., Conclusion: PET/CT is a powerful fusion of two pre-existing imaging modalities, which not only improves the diagnostic value in restaging DTC patients with elevated Tg and negative 131I scan, but also provides accurate information regarding subsequent treatment options and may lead to a change in treatment management.

Introduction: The aim of our study was to determine whether treatment with a long-acting somatostatin-receptor analogue is effective in patients with (131)I-negative but somatostatin-receptor-positive metastases from dedifferentiated and anaplastic thyroid cancer., Materials and Methods: Twelve patients were screened for the study. All of them showed progressive disease confirmed by radiologic evaluation, increasing serum thyroglobulin (Tg), and negative diagnostic or posttherapeutic (131)I whole-body scans (WBS). Eight of 12 patients (4 males and 4 females; age range, 57-89 years; 1 papillary thyroid cancer; 4 poorly differentiated follicular thyroid cancer; 1 follicular and anaplastic thyroid cancer; 2 anaplastic thyroid cancer) showed positive somatosatin-receptor expression in Tc-99m depreotide WBS/SPECT (Tc-99m Dep.WBS). Initially, in all patients fluorine-18 2-fluoro-2- D-glucose-positron emission tomography-computed tomography ((18)F-FDG-PET-CT), Tc-99m Dep.WBS, and Tg measurements were performed. In the case of positive receptor scintigraphy, patients were treated with 20mg Sandostatin LAR (Novartis Pharmaceuticals, Basel, Switzerland) once per month intramuscularly over a period of 6 months followed by repeated (18)F-FDG-PET-CT, Tc-99m Dep.WBS, and Tg measurement to determine metabolic activity and tumor size. In case of tumor progression, the dose was increased to 30mg of Sandostatin LAR once per month., Results: Only 3 patients were able to undergo long-term treatment. Two patients were treated with octreotide long-acting release (LAR) for 1 year and 1 patient for 1(1/2) years. All patients showed progressive disease during the treatment: an increase of serum Tg on one hand and an increase in the number of lesions and extent in tumor size visible on FDG-PET-CT and Tc-99m Dep.WBS on the other. During the treatment there was no change in receptor expression, nevertheless, clear tumor progression under therapy with a somatostatin analogue was visible in FDG-PET-CT and in Tc-99m Dep.WBS., Conclusion: Our data demonstrate that all of our patients treated with a somatostatin analogue showed clinical progression and that our attempt to achieve a stabilization of the disease failed.

There is no doubt that the availability of recombinant human thyrotropin (rhTSH) is one of the milestones in the management of patients with differentiated thyroid cancer (DTC). It offers the opportunity to obtain representative serum thyroglobulin (Tg) levels and diagnostic whole-body scanning (Dx WBS) with 131I under adequate TSH elevation, while the patient continues to receive thyroid hormone. But rhTSH is also used with success in the treatment of local recurrences and distant metastases. In this retrospective analysis we were able to show that our excellent clinical experiences with the use of rhTSH (rare side effects and high compliance) could also be demonstrated by sufficiently elevated TSH levels and representative stimulated Tg measurements. Since April 2001 most of the patients with thyroid cancer in our hospital have undergone diagnostic examination (205 patients underwent 319 examinations) and 131I therapy (a total of 68 treatments) with rhTSH stimulation excluding the first radioiodine ablation of remnants after initial thyroidectomy. Our results show that under rhTSH stimulation 83.5% (diagnostic group) and 88% (therapy group) of our patients with DTC obtained a TSH level of greater than 80 mU/L after two injections of rhTSH (Thyrogen, Genzyme Corp., Cambridge, MA) 0.9 mg intramuscularly 24 hours and 48 hours before the administration of 131I. Only 2.3% (diagnostic group) and 0% (therapy group) demonstrated TSH levels less than 50 mU/L. Serum Tg levels under rhTSH-stimulated conditions showed that in 81.2% the serum Tg maximum was obtained on day 5. Because of the costs associated with periodically rhTSH-assisted Tg testing and based on the data of other studies we are now testing mainly on day 5 to identify residual tumor mass and to compare these Tg levels in the follow-up. Our experience demonstrates that the administration of rhTSH is a safe, effective, and-from an economic point of view- valuable tool in the management of patients with DTC.