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Background: Outcomes vary among patients with radioiodine refractory (RR) differentiated thyroid cancer (DTC). The prognostic factors for survival are not well-known, resulting in difficulty in selecting patients for new targeted therapies. We assessed overall survival (OS) and cancer-specific survival (CSS) from RR-DTC to identify prognostic factors associated with survival., Patients and Methods: The data on all cases of metastatic RR-DTC treated in our center from 1990 to 2011 were retrospectively reviewed. Survival was estimated using the Kaplan-Meier method; associated prognostic factors were assessed using Cox's model., Results: Of 153 cases of metastatic DTC, 59% (n = 91) met a criterion for RR: that is, 60% (n = 55) had at least 1 metastasis without (131)I uptake; 21% (n = 19) had progressive disease (PD) despite (131)I; 19% (n = 17) had persistent disease despite a cumulative activity of (131)I of ≥600 mCi. After the diagnosis of RR, median OS was 8.9 years (95% confidence interval [CI]: 5.4-NR); median CSS was 9.6 years (95% CI: 6.01-NR). In multivariate analyses, PD despite (131)I as a criterion for RR disease and the time from initial diagnosis of DTC to diagnosis of RR <3 years were the only independent prognostic factors for poor OS and CSS. Thyroglobulin doubling time (Tg-DT) was assessed in 31 of 91 cases. Among the 11 patients with Tg-DT for <1 year or undetectable Tg, 6 deaths occurred, whereas only 3 died of 20 patients with Tg-DT >1 year or negative Tg-DT., Conclusion: The identification of prognostic factors for decreased survival in RR-DTC may improve the selection of patients for targeted agents., Implications for Practice: This study shows a great heterogeneity in terms of prognosis in radioiodine refractory differentiated thyroid carcinoma. Poorer prognosis is observed in patients with tumor progression or with a diagnosis of radioiodine resistance within 3 years after the initial diagnosis of thyroid cancer. Those findings could lead to improvements in the selection of patients for targeted therapies., (©AlphaMed Press.)

Aim: To assess the interest of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET/CT) to evaluate the tumor response after radiotherapy (RT) in anaplastic thyroid cancer (ATC) patients., Methods and Materials: 92 patients were treated for ATC at our institution from 1987 to 2012, out of which 64 (70%) received an aggressive multimodal treatment and 28 (30%) a palliative treatment. In the multimodal treatment group, curative-intended surgery, chemotherapy, and RT were delivered in 35 (55%), 59 (92%), and 56 (88%) patients. The maximum standardized uptake value (SUVmax) was determined in tumor (T), nodes (N) and metastases (M) in each available (18)F-FDG PET/CT., Results: The median follow-up was 3.2years. The 1-year actuarial overall survival (OS) was 18% (median: 5.2months) in the entire population and 27% (median: 7months) in the multimodal treatment group. In the multivariate analysis, RT, surgery, and pre-RT chemotherapy independently predicted for OS, with HRs respectively of 0.1, 0.3, and 0.5. Quantification of FDG uptake with SUVmax was assessable in 26 (40%), 19 (30%), and 25 (39%) of (18)F-FDG PET/CT performed initially (prior to any treatment), prior to RT, and after RT, respectively. Mean SUVmax significantly decreased in T (p<0.001), but not in N (p=0.1) and M (p=0.3) during the assessment period, which might be related to the local effect of RT. Comparing pre- and post-RT (18)F-FDG PET/CT, the T mean relative SUVmax decrease was lower (23±54%) in the 4 patients that had a local relapse (LR) as compared with others in the 12 others patients (62±33%; p=0.3). A relative SUVmax decrease inferior to 20% significantly predicted for LR (p=0.02)., Conclusion: The prognosis of ATC patients remains dismal despite an aggressive multimodal treatment. Although our results were not significant, (18)F-FDG PET/CT could potentially serve as a surrogate marker of treatment response in ATC., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: Aggressive histopathologic subtypes of differentiated thyroid cancer (DTC) are fluorodeoxyglucose (FDG)-avid tumors and are at high risk for persistent/recurrent disease. In these patients, fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is performed in cases of suspicion of recurrence based on thyroglobulin (Tg) levels or thyroglobulin antibodies (TgAb). The goals of this study were to evaluate the sensitivity of systematic postoperative FDG-PET/CT and to identify risk factors for abnormal FDG-PET/CT., Methods: Single-center retrospective study of 38 consecutive patients (16 males, 22 females; mean age, 57 years) with aggressive histology DTC, without known persistent disease at the time of postoperative radioactive iodine (RAI) ablation. The most frequent aggressive histologic subtypes were tall cell papillary carcinoma (45%) and poorly differentiated carcinoma (42%)., Results: A total of 86 lesions were found in 20 (53%) patients, distributed in 33 organs. FDG-PET/CT and the postablation whole-body scan (RAI WBS) showed persistent disease in 15 and 12 patients, respectively. FDG-PET/CT was more sensitive than WBS for the detection of individual lesions (69% vs. 59%). Both imaging techniques were complementary with 41% of the lesions detected only by FDG-PET/CT and 31% only by RAI WBS. The only risk factor of abnormal FDG-PET/CT was a stimulated Tg level (Tg/TSH) measured at ablation >10 ng/mL with persistent disease showing FDG uptake in 72% of the patients with a Tg/TSH >10 ng/mL and in 10% of the patients with Tg/TSH ≤10 ng/mL., Conclusion: Postoperative FDG-PET/CT should be performed routinely in patients with aggressive histology DTC.

Purpose of Review: Radioactive iodine (RAI) is administered postoperatively to the majority of thyroid cancer patients. No available study has demonstrated any benefit in low-risk patients., Recent Findings: RAI should be used selectively in low and intermediate-risk patients, based on the surgical and pathological reports and on postoperative serum thyroglobulin level and neck ultrasonography. When used, a low activity (30 mCi) is administered following recombinant human thyrotropin stimulation. High-risk patients are treated with a high activity of RAI (100 mCi or more)., Summary: RAI is not administered in many low-risk patients who can be reliably followed up with serum thyroglobulin determination on L-thyroxine treatment and neck ultrasonography. RAI may be administered in case of abnormality, and this delay will not reduce the chance of cure.

Objective: Cervical ultrasound (US) scan is a key tool for detecting metastatic lymph nodes (N1) in patients with papillary thyroid cancer (PTC). N1-PTC patients are stratified as intermediate-risk and high-risk (HR) patients, according to the American Thyroid Association (ATA) and European Thyroid Association (ETA) respectively. The aim of this study was to assess the value of post-operative cervical US (POCUS) in local persistent disease (PD) diagnosis and in the reassessment of risk stratification in N1-PTC patients., Design: Retrospective cohort study., Methods: Between 1997 and 2010, 638 N1-PTC consecutive patients underwent a systematic POCUS. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of POCUS for the detection of PD were evaluated and a risk reassessment using cumulative incidence functions was carried out., Results: After a median follow-up of 41.6 months, local recurrence occurred in 138 patients (21.6%), of which 121 were considered to have PD. Sensitivity, specificity, NPV, and PPV of POCUS for the detection of the 121 PD were 82.6, 87.4 95.6, and 60.6% respectively. Cumulative incidence of recurrence at 5 years was estimated at 26% in ETA HR patients, 17% in ATA intermediate-risk patients, and 35% in ATA HR patients respectively. This risk fell to 9, 8, and 11% in the above three groups when the POCUS result was normal and to <6% when it was combined with thyroglobulin results at ablation., Conclusion: POCUS is useful for detecting PD in N1-PTC patients and for stratifying individual recurrence risk. Its high NPV could allow clinicians to tailor follow-up recommendations to individual needs., (© 2014 European Society of Endocrinology.)