Eosinophil Cationic Protein in Patients with Differentiated Thyroid Cancer Treated with Radioactive Iodine 131.

Published data indicate the involvement of eosinophil granulocytes and eosinophil cationic protein (ECP) in tumor defense. The aim of this study was to analyze serum ECP concentrations in patients with differentiated thyroid cancer (DTC) before, 3 days and 7 days after radioactive iodine (131-I) therapy. Association of ECP concentrations with histological type of tumor, stage of disease and/or levels of selected T-helper 2 (Th2) cytokines was examined. The study population included 17 DTC patients and 10 control subjects. ECP was measured by fluoroimmunoassay (FIA). Th2 (cytokines interleukin 4 (IL-4), interleukin 5 (IL-5), and interleukin 13 (IL-13)) were determined by enzyme-linked immunosorbent assays (ELISA). We found that ECP values in DTC patients before radioactive iodine therapy were approximately two-fold higher than in the controls, but the difference was statistically significant only if the patients with DTC and associated Hashimoto thyroiditis (HT) were included. There was no correlation between the serum concentrations of IL-5 and ECP. Radioactive iodine therapy led to a decrease in serum ECP level which did not follow the decline in serum protein levels. Additional studies are needed to determine the significance of these findings.

Vitamin B12 levels are not affected by radioiodine ablation of the thyroid.

OBJECTIVE: Radioiodine administered for the treatment of hyperthyroidism and thyroid cancer can be taken up by many non-thyroid tissues which express sodium iodide symporter. Though gastric mucosa takes up radioiodine, its impact on parietal cell has not been evaluated. The aim of the present study was to compare vitamin B12 and homocysteine concentrations in patients with thyroid disorders treated by radioiodine ablation with those in control population without radioiodine exposure. METHODS: Patients with Graves' disease, toxic multinodular goiter (TMNG), toxic adenoma (TA) or differentiated thyroid cancer (DTC) who had received 131I were included as "patients". Healthy persons and patients having Graves' disease but without exposure to radioiodine were recruited as "controls". A total of 35 patients and 35 controls were included. Patients were divided into Graves' disease and non-Graves' disease (TMNG, TA, DTC) groups. Graves' disease patients were compared with Graves' disease controls while non-Graves' disease patients were compared with healthy controls. RESULTS: In the Graves' disease group, median vitamin B12 concentration was 240 pg/ml (IQR: 148 - 371) in patients (n=23) and 195 pg/ml (IQR: 140 - 291 pg/ml) (p=0.13, ns) in controls (n=24). In the non-Graves' disease group, median serum vitamin B12 concentration was 147 pg/ml (IQR: 124 - 325pg/ml) in patients (n=12) and 190 pg/ml (IQR: 157 - 373 pg/ml) (p=0.34, ns) in healthy controls (n=11). Homocysteine concentrations were also similar in compared groups of patients and controls. CONCLUSIONS: Radioiodine ablation does not cause vitamin B12 deficiency. However, a prospective study with a larger number of patients is required to confirm this finding.

Matrix metalloproteinase-9 and the Cu/Zn ratio as ancillary diagnostic tools in distinguishing between the classical and follicular variants of papillary thyroid carcinoma.

The most common histological variants of papillary thyroid carcinoma (PTC), classical (CPTC) and follicular (FPTC), have different diagnostic features, molecular biology, and prognosis. Matrix metalloproteinase-9 (MMP-9) endopeptidase which degrades the components of the extracellular matrix is essential in the invasive growth and metastasizing of malignant tumors. The serum copper (Cu)/zinc (Zn) ratios are sensitive diagnostic and prognostic indicators in oncology since Cu- and Zn-dependent enzymes play important roles in the genesis and the progression of tumors. The aim of this study was to examine the expressions of MMP-9 in tissues of CPTC and FPTC, as well as to determine the Cu/Zn ratios in the same samples. MMP-9 was determined immunohistochemically, and the concentrations of copper and zinc in thyroid tissue were determined by means of flame atomic absorption spectrometry. The results obtained revealed significantly higher expressions of MMP-9 in CPTC in comparison with FPTC, as well as higher Cu/Zn ratios in CPTC than in FPTC. Thus, determining MMP-9 activities and the Cu/Zn ratios could improve the accuracy of the standard histopathological diagnosis of these two types of PTC.

Follicular-patterned tumors of the thyroid: the battle of benign vs. malignant vs. so-called uncertain.

This article will review the controversial area of follicular-patterned thyroid tumors. The literature is discussed with emphasis on pathologic diagnosis and the criteria for malignancy. In addition, the current state of knowledge regarding molecular markers and their utility in diagnosing benign from malignant nodules is described. Finally, the apparent lack of consistency with regard to results of certain immunohistochemical markers is included.

Value of ultrasound and cytological classification system to predict the malignancy of thyroid nodules with indeterminate cytology.

Although fine-needle aspiration cytology is considered the gold standard for evaluating thyroid nodules, in about 10-30% of the cases, cytology is indeterminate. This study aimed to determine the value of cytological classification system and ultrasound (US) to predict malignancy in indeterminate thyroid nodule. This retrospective analysis enrolled 80 patients surgically treated at a single center, 75% (60) with benign vs. 25% (20) with malignant lesions at final histology. The clinical, scintigraphic, sonographic, and cytological classification (Bethesda) variables were analyzed in these selected cases of indeterminate cytology, and a prediction model was designed after the multivariate analysis. There was a 25% prevalence of malignancy (20/80). There were no differences in gender, serum thyroid-stimulating hormone and FT4 levels, thyroid auto-antibodies, thyroid dysfunction, and scintigraphic results between benign and malignant nodule groups. The border irregularity in sonographic study was at increased risk for malignancy. The cytological analysis based on Bethesda System (category IV) was an independent predictor for malignancy in indeterminate thyroid nodules. After the multivariate analysis, the model obtained showed border irregularity and Bethesda System category IV as predictive factors of malignancy in indeterminate thyroid nodules, featuring 76.9% of accuracy. This study confirmed a significant increase of risk for malignancy in thyroid nodules with indeterminate cytology showing Bethesda System category IV and suspicious features at US. These findings enhance our current limited predictive armamentarium and can be used to guide surgical decision making.

Decreased 1-25 dihydroxyvitamin D3 concentration in peripheral blood serum of patients with thyroid cancer.

BACKGROUND AND AIMS: Vitamin D(3), in addition to its role in calcium homeostasis, has been recognized as playing a role in human cancer development. However, little is known about the association between vitamin D status and the development of thyroid cancer. This study aimed to investigate vitamin D metabolism by measuring 25(OH) D(3), 1-25 (OH)(2) D(3), PTH and calcium concentrations in the peripheral blood of patients with different forms of thyroid tumors. METHODS: The 25-hydroxyvitamin D(3) ,1-25- dihydoxyvitamin D(3), PTH and calcium serum levels of 50 consecutive patients with epithelial thyroid cancer 27 cases of papillary cancers (PTC), 16 follicular cancers (FTC), and seven cases of anaplastic cancers (ATC) and 34 multinodular nontoxic goiter (MNG) were measured by specific immunoassay. The control group consisted of 26 healthy volunteers. RESULTS: Our results revealed significantly lower 1-25 (OH)(2) D(3) concentration in the PTC group (22.67 pg/mL +/- 8.12; p <0.05), FTC group (16.09 pg/mL +/- 6.15; p <0.02) and ATC group (9.48 pg/mL +/- 5.18; p <0.02). Levels of 1-25 (OH)(2) D(3) varied by cancer stage and were also significantly different. A significant decrease in circulating 1-25 (OH)(2) D(3) concentration was found in patients with stage I (24.12 pg/mL +/- 6.77; p <0.05), stage II (16.93 pg/mL +/- 4.55; p <0.05), stage III (12.44 +/- 8.98; p <0.02) and in stage IVa (6.18 +/- 2.22; p <0.01). There were no significant differences when comparing serum levels of 25(OH) D(3), PTH or calcium concentrations among individuals with multinodular goiter, thyroid cancer and age- and sex-matched control volunteers. CONCLUSIONS: Our study revealed that impaired vitamin D(3) metabolism may play an important role in thyroid follicular cell oncogenesis.

Thyrotropin variations may explain some positive radioiodine therapy scans in patients with negative diagnostic scans.

UNLABELLED: Thyroglobulin (Tg) is a specific marker of residual thyroid cancer or tumor recurrence. In patients with elevated Tg levels and negative diagnostic radioiodine (131I) whole-body scans (dWBS), administration of a therapy dose may reveal foci that were not initially apparent. The aim of this study was to identify factors, other than 131I activity, which might explain why a post-therapy 131I whole-body scan is sometimes positive despite a negative dWBS. PATIENTS AND METHODS: We reviewed data on all patients with elevated Tg levels and negative dWBS with 185 MBq 131I off-T4 at followup, who subsequently received an empiric therapy dose of 3700 MBq of 131I. During a 5-yr period, 22 patients met these criteria. 131I therapy could be given immediately after negative dWBS in 9 patients, with an average of 8 extra days of hypothyroidism. In the other 13 patients, therapy was given an average of 8 months later. RESULTS: The therapy scan was negative in 16 patients, while it showed uptake in the thyroid bed in 5 patients and distant metastases in two. In the latter two patients, the TSH level was suboptimal at the time of dWBS (9 and 25 microIU/ml), and had risen to 34 and 70 microIU/ml respectively at the time of therapy. Overall, a positive scan following therapy occurred in 7 patients (6/9 patients treated immediately and 1/13 patients treated in a separate setting; p<0.01). In patients with positive therapy scans, the mean TSH level was 73 microIU/ml at the time of dWBS and 103.5 microIU/ml at the time of therapy (41% increase; p<0.05). In patients with negative therapy scans the mean TSH level was 84 microIU/ml at dWBS and 86 microIU/ml at the time of the therapy scan (2% increase). CONCLUSIONS: Our study suggests that interval increase in TSH level with a longer period of stimulation may have contributed to making the whole-body scan positive at the time of therapy. Nowadays, patients with elevated Tg are directly given a therapy dose of 131I. Special care should be taken when preparing patients who have been on suppressive levothyroxine therapy for a long time, in order to avoid misclassifying the tumor as non-functioning.

Contribution of gamma probe-guided surgery to lateral approach completion thyroidectomy.

OBJECTIVE: To evaluate the effectiveness of gamma probe performed with technetium Tc 99m-labeled pertechnetate in patients who underwent completion thyroidectomy after pathologic detection of incidental thyroid cancer following subtotal thyroidectomy. METHODS: In this prospective study, we evaluated findings from patients with multinodular goiter who underwent gamma probe-guided lateral approach completion thyroidectomy after the pathologic detection of incidental thyroid cancer following subtotal thyroidectomy where partial thyroid tissue was left unilaterally or bilaterally. Patients who underwent the procedure between January 2003 and January 2007 were included. Thyroid scintigraphy; thyroid and neck ultrasonography examinations; and concentrations of thyroid hormones, thyrotropin (TSH), thyroglobulin, and thyroglobulin antibodies were evaluated before the second operation. Patients were administered 3 mCi technetium Tc 99m pertechnetate during anaesthetic induction, and we extracted suspicious thyroid tissue and tissue with activity above background activity levels according to gamma probe. Extracted tissues were evaluated pathologically. RESULTS: Completion thyroidectomy was performed in 23 patients. Seventy-nine tissue samples were extracted; 49 were thyroid tissue and 30 were nonthyroid tissue. Mean thyroid tissue to background activity ratio (T:B) was 6.4 +/- 3.9 (range, 2-14.3), and mean thyroid bed (after excision) to background activity ratio (Tbed:B) was 1.2 +/- 0.2 (range, 0.8-1.7) (P = .001). Mean T:B and Tbed:B ratios of the nonthyroid tissue were 1.2 +/- 0.3 (range, 0.2-1.7) and 1.1 +/- 0.2 (range, 0.4-1.4), respectively (P = .001). The thyroid tissue T:B ratio was significantly higher than that of non-thyroid tissue (P<.001). Gamma probe labeling contributed to extraction of small amounts of thyroid tissue that could not be viewed by scintigraphy in 43% of patients. CONCLUSIONS: Using gamma labeling, thyroid tissue shows significantly more activity than nonthyroid tissue. Gamma probe helps detect small, residual thyroid tissue that is buried in the scar tissue that cannot be distinguished by scintigraphy; therefore, it assists in the extraction of the maximum amount of thyroid tissue.

Diagnostic and therapeutic use of recombinant human TSH (rhTSH) in differentiated thyroid cancer.

Traditionally, withdrawal of thyroid hormone to increase serum levels of thyroid-stimulating hormone (TSH) has been used in patients with differentiated thyroid carcinoma (DTC) to optimize radio-iodine uptake and serum thyroglobulin (Tg) stimulation during follow-up and in preparation for radio-iodine therapy. However, this procedure is associated with signs and symptoms of hypothyroidism which negatively affect the patient's quality of life. Recombinant human thyrotropin (rhTSH) has provided an effective alternative to thyroid hormone withdrawal. After favourable experimental trials in humans, rhTSH obtained regulatory approval in North America and in Europe as a diagnostic tool, and more recently as a preparation for radio-iodine thyroid remnant ablation. Since then, rhTSH has radically changed the diagnostic and therapeutic management of DTC patients. This review will focus on the clinical application of rhTSH in the management of DTC, highlighting current indications and future perspectives.

Serum thyroglobulin determination in thyroid cancer patients.

Serum thyroglobulin determination plays a central role, in combination with neck ultrasonography, in the follow-up of thyroid cancer patients. Its specificity is improved by thyroid remnant ablation, and its sensitivity is optimal following prolonged withdrawal or stimulation with recombinant human thyroid-stimulating hormone (TSH). Modern methods with an improved functional sensitivity may facilitate its use during follow-up.

Rosiglitazone effect on radioiodine uptake in thyroid carcinoma patients with high thyroglobulin but negative total body scan: a correlation with the expression of peroxisome proliferator-activated receptor-gamma.

BACKGROUND: Thyroid carcinoma patients with high thyroglobulin (Tg) level but negative total body scan (TBS) are difficult to treat with radioiodine (RAI). The objective of this study was to determine if treatment with rosiglitazone (RZ), a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist, was associated with an increase in RAI uptake in thyroid carcinoma patients with high serum Tg and negative TBSs. We also determined if there was a correspondence between the effect of RZ and the degree of staining for PPAR-gamma within thyroid cancer tissues. METHODS: We prescribed 8 mg of RZ daily for 6 weeks in 23 patients with epithelial cell thyroid carcinoma who previously had negative posttherapeutic I-131 total body scans (post Rx TBSs) with high serum Tg concentrations. Diagnostic total body scans (Dx TBSs) before and 6 weeks after RZ treatment were compared. An ablative dose of I-131 was then given to all patients, and post Rx TBS was performed to evaluate RAI uptake. Immunohistochemical staining of PPAR-gamma expression in thyroid cancer biopsies was done to correlate this with possible effects of RZ on RAI uptake. RESULTS: Seven patients had strong PPAR-gamma-positive staining in thyroid biopsies, nine patients had weakly positive staining, and seven patients had negative staining. Five of seven patients with strong staining had either positive post Rx TBS, or both Dx TBS and post Rx TBS. One of nine patients with weak staining had positive Dx TBS and post Rx TBS. In contrast, none of the seven patients with negative staining had positive TBS. CONCLUSIONS: RZ can increase RAI uptake in thyroid tissue in the majority of patients with epithelial cell thyroid carcinoma whose previous posttherapeutic I-131 scans were negative provided they have high intensity and extent of PPAR-gamma expression in thyroid tissue. Few, if any, patients with weak or no PPAR-gamma expression in thyroid cancer tissue increase RAI uptake after RZ treatment.

Measuring thyroglobulin and thyroglobulin autoantibody in patients with differentiated thyroid cancer.

Measurement of serum thyroglobulin is primarily used as a tumor marker in the postoperative management of patients with differentiated thyroid cancer. Unfortunately, the technical quality of current thyroglobulin assay methods varies and influences the clinical utility of this test. Two different methodologic approaches are used to measure serum thyroglobulin: the original competitive radioimmunoassay methodology and noncompetitive immunometric assay methods. Although the newer immunometric assays offer the technical benefits of eliminating the use of isotopes, using smaller specimen volumes, and having higher sensitivity potential, shorter turnaround times and the convenience of automation, immunometric assays also have a higher propensity for interference from both thyroglobulin autoantibodies and heterophilic antibodies, if present in the specimen. It is critical that physicians understand the technical limitations inherent in thyroglobulin measurement in order to effectively use this test for the postoperative management of patients with differentiated thyroid cancers.

Limited value of repeat recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin testing in differentiated thyroid carcinoma patients with previous negative rhTSH-stimulated thyroglobulin and undetectable basal serum thyroglobulin levels.

CONTEXT: One year after initial treatment, low-risk differentiated thyroid cancer (DTC) patients undergo recombinant human (rh)TSH-stimulated serum thyroglobulin (Tg) (rhTSH-Tg) and neck ultrasound (US). OBJECTIVE: The need for more rhTSH-Tg in these patients is controversial. We evaluated the utility of a second rhTSH-Tg in DTC patients 2-3 yr after their first evaluation. RESULTS: At the first rhTSH-Tg, basal and stimulated serum Tg was undetectable in 68 of 85 patients. Neck US was unremarkable in all but one, who had evidence of lymph node disease. Seventeen of 85 patients had undetectable serum Tg that became positive after rhTSH, with negative imaging in 10 and evidence of disease in seven. Patients with no evidence of disease were reevaluated 2-3 yr later (second rhTSH-Tg). In patients in which the first stimulated Tg was undetectable, all had undetectable basal serum Tg, which remained undetectable after rhTSH in 66 of 67 patients (98.5%) and became detectable in one (1.5%) (positive neck US). In the 10 patients with detectable stimulated Tg in the first test, basal serum Tg and US were negative at the second test, but rhTSH-Tg became detectable in six. Compared with the first rhTSH-Tg, the second stimulated Tg in these six patients decreased in one, increased in three, and stabilized in two patients. CONCLUSIONS: The second rhTSH-Tg was informative in patients who had first stimulated Tg detectable but not in those who had undetectable Tg at the first test, in which the only patient with recurrence was diagnosed by neck US. Thus, rhTSH-Tg should be repeated only in patients who have had a positive first rhTSH-Tg and negative imaging.

[On-levothyroxine measurement of thyroglobulin is not a reliable test for the follow-up of patients at high risk for remnant/recurrent differentiated thyroid carcinoma].

INTRODUCTION: At present the most widely accepted tool for follow-up management of differentiated thyroid cancer (DTC) patients is serum thyroglobulin (Tg) measurement. It is not uncommon for the serum Tg level to be measured while the patient is taking thyroid hormones (on-treatment Tg measurement). The purpose of the study was to evaluate the accuracy of on-treatment measurement of serum Tg in detecting remnant/recurrent or metastatic disease in high-risk DTC patients. MATERIAL AND METHODS: We retrospectively analysed the medical records of 26 high-risk DTC patients and compared the on-treatment and off-treatment Tg levels of these patients. All patients were anti-Tg negative. Using off-treatment measurement of Tg as the gold standard, the results of on-treatment measurement of Tg in the diagnosis of remnant/recurrent disease were analysed for sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV). RESULTS: The median serum Tg level under thyroid hormone suppressive therapy (on-treatment Tg) was 16.5 ng/ml and after withdrawal of thyroid hormone suppressive therapy (off-treatment Tg) was 95.0 ng/ml (P value = 0.001). In 6 patients (23%) the on-treatment Tg level missed the recurrence of the disease. Regarding the off-treatment Tg as the gold standard, the sensitivity, specificity, PPV and NPV of the on-treatment Tg measurement were 72.7%, 100%, 100%, and 40% respectively. CONCLUSION: Normal serum Tg level without TSH-stimulation (on-treatment) is not diagnostically reliable in the follow-up of DTC patients with a high probability of residual/recurrent or metastatic disease.

Comparison of seven serum thyroglobulin assays in the follow-up of papillary and follicular thyroid cancer patients.

BACKGROUND: Serum thyroglobulin (Tg) is the marker of differentiated thyroid cancer after initial treatment and TSH stimulation increases its sensitivity for the diagnosis of recurrent disease. AIM: The goal of the study is to compare the diagnostic values of seven methods for serum Tg measurement for detecting recurrent disease both during L-T4 treatment and after TSH stimulation. METHODS: Thyroid cancer patients who had no evidence of persistent disease after initial treatment (total thyroidectomy and radioiodine ablation) were studied at 3 months on L-T4 treatment (Tg1) and then at 9-12 months after withdrawal or recombinant human TSH stimulation (Tg2). Sera with anti-Tg antibodies or with an abnormal recovery test result were excluded from Tg analysis with the corresponding assay. The results of serum Tg determination were compared to the clinical status of the patient at the end of follow-up. RESULTS: Thirty recurrences were detected among 944 patients. A control 131I total body scan had a low sensitivity, a low specificity, and a low clinical impact. Assuming a common cutoff for all Tg assays at 0.9 ng/ml, sensitivity ranged from 19-40% and 68-76% and specificity ranged from 92-97% and 81-91% for Tg 1 and Tg2, respectively. Using assays with a functional sensitivity at 0.2-0.3 ng/ml, sensitivity was 54-63% and specificity was 89% for Tg1. Using the two methods with a lowest functional sensitivity at 0.02 and 0.11 ng/ml resulted in a higher sensitivity for Tg1 (81% and 78%), but at the expense of a loss of specificity (42% and 63%); finally, for these two methods, using an optimized functional sensitivity according to receiver operating characteristic curves at 0.22 and 0.27 ng/ml resulted in a sensitivity at 65% and specificity at 85-87% for Tg1. CONCLUSION: Using an assay with a lower functional sensitivity may give an earlier indication of the presence of Tg in the serum on L-T4 treatment and may be used to study the trend in serum Tg without performing any TSH stimulation. Serum Tg determination obtained after TSH stimulation still permits a more reliable assessment of cure and patient's reassurance.

Importance of thyroglobulin levels for diagnosis and monitoring of follicular thyroid carcinoma in an adolescent with severe iodine deficiency.

Optimal management of differentiated thyroid cancer in childhood is undetermined. During monitoring of thyroid carcinoma, serum thyroglobulin (hTG) levels provide valuable information. hTG levels not only increase in differentiated thyroid cancers but also in iodine deficiency because of compensation by the thyroid gland. A 14.6 year-old girl was diagnosed with nodular goiter, subclinical hypothyroidism and severe iodine deficiency. She had a very high hTG level. Despite benign fine-needle aspiration biopsy (FNAB), because the hTG level was still very high after treatment with LT4, thyroidectomy was undergone. Cytopathological examination showed minimally invasive follicular thyroid carcinoma. During follow-up, to exclude the presence of persistent/recurrent disease, the hTG level rose to an undesirably high level after withdrawal of TSH suppressive therapy, and radioiodine ablation therapy was applied. This report shows that even if there is an explanation for nodular goiter and high hTG levels, such as iodine deficiency, malignancy cannot be ruled out without thyroidectomy. FNAB is not reliable especially in iodine deficient areas. Serum hTG measurement is a valuable tool for both diagnosis and follow-up of differentiated thyroid carcinoma in children.

Effects of thyroxine withdrawal in biochemical parameters and cardiac function and structure in patients with differentiated thyroid cancer.

AIM: Patients with differentiated thyroid carcinoma (DTC) are closely monitored during the first decade after diagnosis. At intervals of 1-2 years withdrawal of suppressive doses of T(4) is recommended in order to check thyroglobulin (Tg) levels under increased TSH. T(4) therapy is usually withdrawn for 5 weeks (during the first 3 weeks patients receive treatment with T(3) instead of T(4), and the last 2 weeks stop all medication). There are a few reported studies looking into the effects of T(4) withdrawal in athyreotic patients in terms of biochemical parameters and ultrasound indices. We studied patients with DTC at two time points: during suppressive T(4) treatment and at the end of the T(4) withdrawal protocol in order to identify acute changes that become apparent after 5 weeks of treatment modification. METHODS: Hormonal and biochemical parameters were measured as well as ultrasound indices of cardiac function and structure. RESULTS: Statistically significant increases were found in total cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol and triglycerides with T(4) withdrawal. Creatine phosphokinase showed a striking increase with treatment withdrawal. In addition, liver enzymes, total protein and albumin concentrations increased. Creatinine levels increased significantly and sodium decreased on stopping T(4) treatment. The ultrasound indices of cardiac function and structure did not show significant changes. CONCLUSIONS: Acute hypothyroidism following T(4) withdrawal in DTC patients leads to important biochemical changes without significant alterations in cardiac function and structure. These changes may adversely affect patients, especially older patients or those with other chronic diseases.

Real-time prognosis for metastatic thyroid carcinoma based on 2-[18F]fluoro-2-deoxy-D-glucose-positron emission tomography scanning.

CONTEXT/OBJECTIVE: Approximately 15% of thyroid cancer patients develop subsequent metastases. The clinical course of patients with metastatic thyroid carcinoma is highly variable. We hypothesized that the metabolic activity of metastatic lesions, as defined by retention of 2-[(18)F]fluoro-2-deoxyglucose (FDG), would correlate with prognosis. DESIGN/PATIENTS: The initial FDG-positron emission tomography (PET) scans from 400 thyroid cancer patients were retrospectively reviewed and compared with overall survival (median follow-up, 7.9 yr). We examined the prognostic value of clinical information such as gender, age, serum thyroglobulin, American Joint Committee on Cancer (AJCC) stage, histology, radioiodine avidity, FDG-PET positivity, number of FDG-avid lesions, and the glycolytic rate of the most active lesion. RESULTS: Age, initial stage, histology, thyroglobulin, radioiodine uptake, and PET outcomes all correlated with survival by univariate analysis. However, only age and PET results continued to be strong predictors of survival under multivariate analysis. The initial American Joint Committee on Cancer stage was not a significant predictor of survival by multivariate analysis. There were significant inverse relationships between survival and both the glycolytic rate of the most active lesion and the number of FDG-avid lesions. CONCLUSIONS: FDG-PET scanning is a simple, expensive, but powerful means to restage thyroid cancer patients who develop subsequent metastases, assigning them to groups that are either at low (FDG negative) or high (FDG positive) risk of cancer-associated mortality. We propose that the aggressiveness of therapy for metastases should match the FDG-PET status.