Cervical soft tissue recurrence of differentiated thyroid carcinoma after thyroidectomy indicates a poor prognosis

BACKGROUND

We investigated cervical soft tissue recurrence of differentiated thyroid carcinoma (DTC) after thyroidectomy, and these lesions exhibited no evidence that they were lymph nodes (LNs).

METHODS

Between January 2012 and April 2016, consecutive 6308 patients underwent thyroid surgery for DTC at our center. Among them, we encountered 21 patients with recurrent cervical soft tissue lesions, none of whom had previously undergone fine needle aspiration biopsy (FNAB).

RESULTS

The 21 patients accounted for 0.33% of all 6308 patients, including twenty cases of papillary thyroid carcinoma and one case of follicular thyroid cancer. Approximately half (52.3%) of the recurrence were first detected by ultrasound (US). Eighteen lesions underwent complete preoperative US, but 6 lesions were misdiagnosed as metastatic LNs by US. Therefore, 54 age- and gender-matched recurrent or persistent LNs derived from DTC were randomly selected from the same database. The soft tissue lesions (mean size, 2.30 cm) were larger than the LNs. Fewer hyperechogenic hila and punctuations were found in the group of soft tissue recurrence (P < 0.05). During follow-up, distant metastasis was detected in 38.1% of patients in the soft tissue recurrence group. The distant metastasis rates showed that local soft tissue recurrence led to a poorer prognosis than cervical LN persistence or recurrence (P = 0.00).

CONCLUSIONS

Although the incidence of DTC recurrence in cervical soft tissue was low, it may be a predictor for distant recurrence. To minimize the risk, a long-term postoperative evaluation, preferably with US, should be performed.

Early stimulated thyroglobulin for response prediction after recombinant human thyrotropin-aided radioiodine therapy

OBJECTIVE

Measurement of recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin (Tg) is generally recommended 72 h after the second rhTSH injection. However, due to the acute effect of I-131 on thyrocytes, Tg measured after radioiodine therapy (RIT) would not accurately reflect the thyroid tissue burden. We aimed to determine predictive values of serum Tg level measured just before rhTSH-aided RIT and to compare the results obtained just after RIT in patients with differentiated thyroid carcinoma (DTC).

METHODS

We evaluated 150 patients with DTC who underwent rhTSH-aided RIT (2.96-6.66 GBq) after total thyroidectomy between 2009 and 2014. Serum Tg level was measured 24 h (early Tg) and 72 (or 96) h (delayed Tg) after the second rhTSH injection. An excellent response was defined based on the latest American Thyroid Association Guidelines. Univariate and multivariate analyses were performed for early Tg, delayed Tg, and other clinical variables.

RESULTS

In the multivariate analysis, tumor size [odds ratio (OR) 1.716; 95% confidence interval (CI) 1.019-2.882; p = 0.042] and early Tg level (OR 2.012; 95% CI 1.384-2.925, p < 0.001) independently predicted excellent responses. The cutoff for the best early Tg level to predict a non-excellent response was 2.0 ng/mL. Delayed Tg was not a significant predictor (OR 0.992; 95% CI 0.969-1.015; p = 0.492).

CONCLUSIONS

Early stimulated Tg significantly predicted therapeutic response after rhTSH-aided RIT in patients with DTC. Therefore, serum Tg should be measured before RIT to predict therapeutic responses.

Increased incidence of thyroid cancer in Navarra (Spain). Evolution and clinical characteristics, 1986-2010

INTRODUCTION

The latest published studies show an increased incidence of thyroid cancer worldwide. The aim of this study was to analyze the changes in the incidence of thyroid cancer in Navarra and its clinical presentation regarding sex, histological subtype and size over the last 25 years.

METHODS

Thyroid cancer incidence rates were calculated on the basis of data from the Cancer Registry of Navarra during 1986-2010. Clinical data were obtained from the historical cohort of the Hospital Registry of Cancer of Navarra, which includes all the new cases of differentiated thyroid carcinoma diagnosed and treated in the public health network of this Community in that period.

RESULTS

The overall incidence of thyroid cancer in Navarra increased over the last 25 years, with an increase in the adjusted rate in men from 2.24 (1986-1990) to 5.85 (2006-2010) per 100,000 population/year (P<.001) and in women from 9.05 to 14.04, respectively (P<.001). This increase occurs only in papillary carcinoma. The clinical characteristics of 739 patients with differentiated thyroid cancer were studied. The mean age at diagnosis increased over the years and the predominance of women (about 80%) remains stable. Mean tumor size decreased over the five-year periods from 30.9 to 22.5mm (P<.001), the proportion of microcarcinomas (T1a) increased from 8.8% to 30% (P<.001) and, despite this increase, there were no statistical differences in the TNM stage at diagnosis during the study period. The distribution of histological variants of papillary and follicular carcinoma did not change over 25 years.

CONCLUSIONS

During the period studied, the incidence of thyroid cancer increased in Navarra in both sexes. The increase occurred only in papillary carcinoma, without changes in the distribution of his histological variants. The increase in the proportion of T1a tumors is remarkable, but the TNM stage distribution was maintained. These results suggest an increase in the diagnosis of thyroid microcarcinomas due to changes in clinical practice, without ruling out a real increase in the incidence of papillary carcinoma in Navarra.

Designing and Developing PET-Based Precision Model in Thyroid Carcinoma: The Potential Avenues for a Personalized Clinical Care

This communication enumerates the current uses and potential areas where PET could be clinically utilized for developing "precision medicine" type model in thyroid carcinoma. (1) In routine clinics, PET imaging (with fluorodeoxyglucose [FDG]) is utilized to investigate patients of differentiated thyroid carcinoma (DTC) with high thyroglobulin and negative iodine scintigraphy (TENIS) and in medullary carcinoma thyroid (MCT) when the tumor markers (eg, calcitonin and carcino embryonic antigen [CEA]) are raised postoperatively (PET with FDG, ⁶⁸Ga-DOTA-NOC/TATE, FDOPA). Both are examples of management personalization, where PET-computed tomography (CT) has been found substantially useful in detecting sites of metastatic disease and making decision with regard to feasibility and planning of surgery on an individual patient basis. (2) The next important area of management personalization is in patients of TENIS with metastatic disease not amenable to surgery through examining FDG-PET findings in tandem with radio iodine scan and ⁶⁸Ga-DOTA-TATE/NOC PET/CT. Heterogeneous behavior of the metastatic lesions is frequently observed clinically: analyzing the findings of three studies aids in sub-segmenting patients into subgroups and thereby deciding upon the best approach (observation with LT4 suppression vs PRRT vs tyrosine kinase inhibitors) that could be individualized in a given case. (3) In metastatic/inoperable MCT, ⁶⁸Ga-DOTA-TATE/NOC PET-CT helps in deciding upon feasibility of targeted PRRT in an individual patient and helps in follow-up and response evaluation. (4) Disease prognostification with FDG-PET is evolving both in DTC and MCT, where FDG avidity would indicate an aggressive biology, though the implication of this from treatment viewpoint is unclear at this point. Conversely, a negative FDG-PET in DTC and TENIS would suggest a favorable prognosis in an individual. (5) Iodine-124 PET/CT has the added potential of obtaining lesional dosimetry compared to the SPECT approach, and could help in selecting appropriate doses on an individual basis.

A bicentric study

SPECT/CT detects radioiodine-positive cervical lymph node metastases (LNMs) of differentiated thyroid carcinoma (DTC) at the time of postsurgical radioablation (RA). Preliminary evidence indicates that the majority of LNMs are successfully treated by RA. The aim of this study was to confirm this evidence in a bicentric setting and to evaluate whether size is a predictor for successful elimination.

PATIENTS AND METHODS

Since 01/2007 and 05/2008, respectively, SPECT/spiral-CT is performed routinely in all patients with DTC at RA in two University Clinics. The outcome of iodine-positive LNMs identified by SPECT/CT until 12/2012 was analyzed by follow-up diagnostic ¹³¹I scans and serum thyreoglobulin (Tg) values. LNM volume and short-axis diameter were evaluated as prognostic factors by a receiver-operating characteristic (ROC) analysis.

RESULTS

79 patients with 97 iodine-positive LNMs were included. Surgery was carried out in 8 patients with 13 LNMs due to the presence of additional iodine-negative lesions. Of the remaining 84 LNMs, 74 (88%) were successfully treated as demonstrated by radioiodine scans at follow-up. 10 LNMs persisted. 67/70 LNMs smaller than 0.9 ml were treated successfully, whereas this was the case of only 6/14 exceeding this threshold. Using this cut-off level to predict treatment success, sensitivity, specificity, positive and negative predictive value were 92%, 73%, 96%, and 57%. Results for short-axis diameter (cut-off level < 1cm) were 90%, 69%, 94% and 56%.

CONCLUSION

RA is effective in the treatment of the majority of ¹³¹I-positive LNMs identified in SPECT/CT images. In this study, 88% of iodine-positive LNM in DTC were successfully treated by radioiodine given at RA. Both LNM volume and diameter are reliable predictors of treatment success.

Diagnostic value of Tg and TgAb for metastasis following ablation in patients with differentiated thyroid carcinoma coexistent with Hashimoto thyroiditis

PURPOSE

This study was designed to investigate the clinical value of serum thyroglobulin (Tg) and antithyroglobulin antibody (TgAb) measurements and the cutoff value after ablation in differentiated thyroid carcinoma (DTC) complicated by Hashimoto thyroiditis (HT) with metastasis.

MATERIALS AND METHODS

We measured serum Tg and TgAb levels and evaluated the disease status in 164 cases of DTC coexistent with HT in pathologically confirmed patients after surgery and post-remnant ablation during a 3-year follow-up. All Tg and TgAb levels were assessed by chemiluminescent immunoassay (IMA). Receiver operating characteristic (ROC) curve analysis was used to evaluate the prognostic value of Tg and TgAb for disease metastasis. The relationship between Tg and TgAb was analyzed using the scatter diagram distribution method.

RESULTS

We found that the cutoff values of Tg and TgAb were 1.48 µg/L and 45 kIU/L, respectively. The area under the ROC curve (AUC) of Tg and TgAb was 0.907 and 0.650, respectively.

CONCLUSIONS

In DTC coexistent with HT patients, the optimal cutoff value correlated with metastasis in Tg and TgAb was 1.48 µg/L and 45 kIU/L, respectively.

Cytogenetic and dosimetric effects of (131)I in patients with differentiated thyroid carcinoma: comparison between stimulation with rhTSH and thyroid hormone withdrawal treatments

A study directed to the cytogenetic and dosimetric aspects of radionuclides of medical interest is very valuable, both for an accurate evaluation of the dose received by the patients, and consequently of the genetic damage, and for the optimization of therapeutic strategies. Cytogenetic and dosimetric effects of (131)I in lymphocytes of thyroidectomized differentiated thyroid cancer (DTC) patients were evaluated through chromosome aberration (CA) technique: Euthyroid patients submitted to recombinant human thyroid-stimulating hormone (rhTSH) therapy (group A) were compared with hypothyroid patients left without levothyroxine treatment (group B). CA analysis was carried out prior to and 24 h, 1 week, 1 month and 1 year after radioiodine administration (4995-7030 MBq) in both groups. An activity-response curve of (131)I (0.074-0.740 MBq/mL) was elaborated, comparing dicentric chromosomes in vivo and in vitro in order to estimate the absorbed dose through Monte Carlo simulations. In general, radioiodine therapy induced a higher total CA rate in hypothyroid patients as compared to euthyroid patients. The frequencies of dicentrics obtained in DTC patients 24 h after treatment were equivalent to those induced in vitro (0.2903 ± 0.1005 MBq/mL in group A and 0.2391 ± 0.1019 MBq/mL in group B), corresponding to absorbed doses of 0.65 ± 0.23 Gy and 0.53 ± 0.23 Gy, respectively. The effect on lymphocytes of internal radiation induced by (131)I therapy is minimal when based on the frequencies of CA 1 year after the treatment, maintaining a higher quality of life for DTC patients receiving rhTSH-aided therapy.

Differentiated thyroid cancer in patients ≥75 years: Histopathological features and results of surgical treatment

INTRODUCTION

The aim of this retrospective study was to investigate clinical and pathologic characteristics of differentiated thyroid cancer (DTC) in patients ≥75 years and to analyze results of surgical treatment in this age group.

METHODS

The clinical records of patients submitted to total thyroidectomy between 2009 and 2014 with histopathological diagnosis of DTC were analyzed. Patients were divided into 3 groups: patients ≤64 years were included in group A, those between 65 and 74 in B and those ≥75 years in C.

RESULTS

Classic papillary thyroid cancer was more frequent in group A, whereas follicular variant of papillary carcinoma, tall cell and follicular carcinoma were more frequent in C. Multicentric and locally invasive tumors were more frequent in group C; younger patients (group A) showed higher incidence of node metastases (12.54% in group A, 6.33% in B and 7.89% in C). Postoperative stay was significantly longer in group C (3.13 ± 1.28 days vs 2.55 ± 1.27 vs 2.89 ± 1.27; p < 0.001). Transient hypoparathyroidism was more frequent in groups A and B compared with C (29.26% vs 19.71% vs 18.42%; p 0.033) whereas transient recurrent laryngeal nerve palsy was more frequent in group C compared with A and B (2.63% vs 0.16% vs 2.11% p 0.009).

CONCLUSIONS

In aging patients DTC show a worse prognosis compared with younger patients due to higher incidence of more aggressive histotypes but also to a significant diagnostic delay. Total thyroidectomy is safe when surgical operation is performed by skilled surgeons. Age alone does not exclude surgical option.

Unusual False Positive Radioiodine Uptake on (131)I Whole Body Scintigraphy in Three Unrelated Organs with Different Pathologies in Patients of Differentiated Thyroid Carcinoma: A Case Series

Three cases with unusual false positive radioiodine uptake in three different organs and pathologies (infective old fibrotic lesion in the lung, simple liver cyst, and benign breast lesion) on iodine-131 (¹³¹I) whole body scintigraphy. Clinicoradiological correlation was undertaken in all three cases and the pathologies were ascertained. In all the three cases, single-photon emission computerized tomography-computed tomography (SPECT-CT) and ancillary imaging modalities were employed and were helpful in arriving at the final diagnosis.

Vitamin D receptor expression is linked to potential markers of human thyroid papillary carcinoma

Genes regulated cell-cell and cell-matrix adhesion and degradation of the extracellular matrix (ECM) have been screened as potential markers of malignant thyroid nodules. The mRNA expression levels of two of them, the ECM protein-1 (ECM1) and the type II transmembrane serine protease-4 (TMPRSS4), were shown to be an independent predictor of an existing thyroid carcinoma. The vitamin D receptor (VDR) is expressed in epithelial cells of the normal thyroid gland, as well as in malignant dividing cells, which respond to the active metabolite of vitamin D by decreased proliferative activity in vitro. We evaluated the relationship between mRNA gene expressions of TMPRSS4, ECM1 and VDR in 21 papillary thyroid carcinoma samples and compared it to 21 normal thyroid tissues from the same patients. Gene expression was considered as up- or down-regulated if it varied by more or less than 2-fold in the cancer tissue relative to the normal thyroid tissue (Ca/N) from the same patient. We found an overall significant adjusted correlation between the mRNA expression ratio (ExR) of VDR and that of ECM1 in Ca/N thyroid tissue (R=0.648, P<0.001). There was a high ExR of VDR between Ca/N thyroid tissue from the same patient (3.06±2.9), which also exhibited a high Ca/N ExR of ECM1 and/or of TMPRSS4 (>2, P=0.05).The finding that increased VDR expression in human thyroid cancer cells is often linked to increased ECM1 and/or TPMRSS4 expression warrants further investigation into the potential role of vitamin D analogs in thyroid carcinoma.

Improving the adoption of thyroid cancer clinical practice guidelines

OBJECTIVES/HYPOTHESIS

To present an overview of the barriers to the implementation of clinical practice guidelines (CPGs) in thyroid cancer management and to introduce a computer-based clinical support system.

DATA SOURCES

PubMed.

REVIEW METHODS

A review of studies on adherence to CPGs was conducted.

RESULTS

Awareness and adoption of CPGs is low in thyroid cancer management. Barriers to implementation include unfamiliarity with the CPGs and financial concerns. Effective interventions to improve adherence are possible, especially when they are readily accessible at the point of care delivery. Computerized clinical support systems show particular promise. The authors introduce the clinical decision making modules (CDMMs) of the Thyroid Cancer Care Collaborative, a thyroid cancer-specific electronic health record. These computer-based modules can assist clinicians with implementation of these recommendations in clinical practice.

CONCLUSION

Computer-based support systems can help clinicians understand and adopt the thyroid cancer CPGs. By integrating patient characteristics and guidelines at the point of care delivery, the CDMMs can improve adherence to the guidelines and help clinicians provide high-quality, evidence-based, and individualized patient care in the management of differentiated thyroid cancer. Laryngoscope, 126:2640-2645, 2016.

Characteristics of contralateral carcinomas in patients with differentiated thyroid cancer larger than 1 cm

Purpose

Traditionally, total thyroidectomy has been advocated for patients with tumors larger than 1 cm. However, according to the ATA and NCCN guidelines (2015, USA), patients with tumors up to 4 cm are now eligible for lobectomy. A rationale for adhering to total thyroidectomy might be the presence of contralateral carcinomas. The purpose of this study was to describe the characteristics of contralateral carcinomas in patients with differentiated thyroid cancer (DTC) larger than 1 cm.

Methods

A retrospective study was performed including patients from 17 centers in 5 countries. Adults diagnosed with DTC stage T1b-T3 N0-1a M0 who all underwent a total thyroidectomy were included. The primary endpoint was the presence of a contralateral carcinoma.

Results

A total of 1313 patients were included, of whom 426 (32 %) had a contralateral carcinoma. The contralateral carcinomas consisted of 288 (67 %) papillary thyroid carcinomas (PTC), 124 (30 %) follicular variant of a papillary thyroid carcinoma (FvPTC), 5 (1 %) follicular thyroid carcinomas (FTC), and 3 (1 %) Hürthle cell carcinomas (HTC). Ipsilateral multifocality was strongly associated with the presence of contralateral carcinomas (OR 2.62). Of all contralateral carcinomas, 82 % were ≤10 mm and of those 99 % were PTC or FvPTC. Even if the primary tumor was a FTC or HTC, the contralateral carcinoma was (Fv)PTC in 92 % of cases.

Conclusions

This international multicenter study performed on patients with DTC larger than 1 cm shows that contralateral carcinomas occur in one third of patients and, independently of primary tumor subtype, predominantly consist of microPTC.

The role of early 18F-FDG PET/CT in therapeutic management and ongoing risk stratification of high/intermediate-risk thyroid carcinoma

Little is known about the role in ongoing risk stratification of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) performed early after radioactive iodine (RAI) ablation in differentiated thyroid carcinoma (DTC). The aim of the study is to investigate whether 18F-FDG PET/CT performed early after RAI ablation is useful to detect disease and to influence therapy and ongoing risk stratification. Patients with high/intermediate risk of recurrent DTC were included. 18F-FDG PET/CT scan was performed within 6 months after RAI ablation. We confirmed results with other imaging techniques, pathology reports, or follow-up. We classified the patient response as excellent, acceptable, or incomplete. Modified Hicks criteria were used to evaluate clinical impact. We included 81 patients with high/intermediate risk of recurrent DTC. Forty-one (50.6%) had positive uptake in 18F-FDG PET/CT, with negative (131)I whole-body scan ((131)I WBS). Sensitivity, specificity, and diagnostic accuracy of 18F-FDG PET/CT were 92.5, 90.2, and 91.4%, respectively. 18F-FDG PET/CT results had an impact on therapy in 38.3% of patients. One year after initial therapy, 45.7% showed excellent response, 8.6% acceptable response, and 45.7% incomplete response. A statistically significant relationship was found between negative 18F-FDG PET/CT and excellent response (80 vs. 12.2%, p < 0.001; OR 52.8). 18F-FDG PET/CT scan performed early in surveillance of patients with high/intermediate-risk thyroid carcinoma provides important additional information not available with conventional follow-up methods and had a high impact on therapy. A negative 18F-FDG PET/CT predicts an excellent response to therapy in the new ongoing risk stratification.

The effect of thyroid stimulating hormone suppressive therapy on bone geometry in the hip area of patients with differentiated thyroid carcinoma

Subclinical hyperthyroidism has been reported to increase the fracture risk. However, the effect of thyroid stimulating hormone (TSH) suppressive therapy on bone geometry in the hip area of patients with differentiated thyroid carcinoma (DTC) is still unclear. The aim of this study was to investigate the effect of TSH suppression on bone geometry in the hip area of pre- and postmenopausal women with DTC. We conducted a retrospective cohort study including 99 women with DTC (25 pre- and 74 postmenopausal) who had received TSH suppressive therapy for at least 3years and 297 control subjects (75 and 222, respectively) matched for sex and age. Bone mineral density (BMD) in the spine and hip area and bone geometry at the femoral neck measured by dual energy X-ray absorptiometry (DXA) were compared between patients and controls. The association between thyroid hormone and bone parameters was investigated. All analyses of bone parameters were adjusted for age, body mass index, and serum calcium levels. In premenopausal subjects, TSH suppressive therapy was not associated with poor bone parameters. In postmenopausal subjects, patients with DTC undergoing TSH suppression showed lower cross-sectional moment of inertia (CSMI), cross-sectional area, and section modulus and thinner cortical thickness at the femoral neck than those of control subjects, whereas their femoral neck BMD was comparable with controls. Total hip BMD was lower in postmenopausal patients than in controls. CSMI and section modulus at the femoral neck were independently associated with serum free T4 levels in postmenopausal patients. The difference in femoral neck bone geometry between patients and controls was only apparent in postmenopausal DTC patients with free T4 >1.79ng/dL (23.04pmol/l), and not in those with free T4 levels ≤1.79ng/dL (23.04pmol/l). TSH suppression in postmenopausal DTC patients was associated with decreased bone strength by altering bone geometry rather than BMD in the hip area, especially the femoral neck. This alteration in bone quality was observed only in patients with free T4 levels above the upper normal limit.

Value of post-therapeutic ¹³¹I scintigraphy in stimulated serum thyroglobulin-negative patients with metastatic differentiated thyroid carcinoma

Metastatic differentiated thyroid carcinoma (DTC) with positive (131)I scintigraphy, but negative stimulated Tg (sTg) is relatively rare in clinical practice. The clinical characteristics of these patients were analyzed in the current study. A total of 3367 consecutive histologically proven DTC patients were analyzed retrospectively from January 2007 to June 2013. Tg negativity was defined as a sTg level of <2 ng/mL without positive anti-Tg antibody (TgAb level of <100 IU/mL) under thyroid-stimulating hormone stimulation (TSH level of ≥30 mIU/L). Analyses were performed using the Statistical Package for the Social Sciences, version 20.0 (SPSS, Chicago, IL, USA). Seventy-one patients (median age 45 years, range 17-68 years) were post-therapeutic (131)I-SPECT/CT positive and sTg negative (PTP-TN) constituting 2.1 % of all patients. Of these 71 patients, 2 (2.8 %) had bone metastasis, 11 (15.5 %) had lung metastasis, and 59 (83.1 %) had lymph node metastasis. Fifty-six patients had cervical lymph node metastasis (cLNM), and US was positive in 15 patients (26.8 %), while negative in 41 patients (73.2 %). When compared to patients with concordant positive results for sTg and (131)I scintigraphy, US showed a relatively lower positive rate in the detection of cLNM in PTP-TN patients (28.8 vs. 53.8 %; χ (2) = 6.70; P = 0.01). In conclusion, even with sTg <2 ng/mL, there is a low risk of metastatic DTC. US had limitations in PTP-TN patients, while post-therapy (131)I-SPECT/CT demonstrated an advantage in the detection of functioning metastasis despite low sTg levels in patients with metastatic DTC.

Discriminant function analysis of the occurrence risk of abnormal electrocardiogram in thyroidectomized differentiated thyroid carcinoma patients with short-term overt hypothyroidism

OBJECTIVES

The common form and risk factors of electrocardiogram (ECG) abnormality in thyroidectomized differentiated thyroid carcinoma (DTC) patients with short-term overt hypothyroidism were investigated and some discriminant formulas for forecasting the occurrence of abnormal ECG in this specific population were deduced in this study.

METHODS

A total of 260 thyroidectomized DTC patients were retrospectively reviewed, 67 of whom had abnormal ECG and 193 normal ECG after short-term (3 weeks) levothyroxine (L-T4) withdrawal. One-way ANOVA, Spearman's rank correlation analysis and discriminant function analysis were performed using data from these DTC patients.

RESULTS

A flat or inverted T wave in inferior myocardial and left ventricular wall leads was the most common abnormal ECG finding in short-term overt hypothyroidism. Statistical analyses showed that age, interval, TSH-end (The serum hormothyrin level at the end of L-T4 withdrawal for 3 weeks), and TSH-vel (The average ascending velocity of serum hormothyrin level during L-T4 withdrawal for 3 weeks) were statistically significant and positively correlated with the occurrence of abnormal ECG. Meanwhile, TSH-vel showed the highest correlation coefficient (r = 0.358, p = 0.000). The formulas, especially deduced from age, interval and TSH-vel, could discriminate patients with abnormal ECG or not as high as 77.6 and 70.5%, respectively (resubstitution accuracy: 72.3%).

CONCLUSION

The thyroidectomized DTC patients undergoing short-term L-T4 withdrawal before their first radioiodine ablative therapy, who had one or more of the above-mentioned risk factors, are likely to show abnormal ECG findings. The formulas from discriminant function analysis may be helpful for predicting patients with abnormal ECG with short-term L-T4 withdrawal and allow appropriate medical intervention beforehand.

Imaging with (124)I in differentiated thyroid carcinoma: is PET/MRI superior to PET/CT?

PURPOSE

The aim of this study was to compare integrated PET/CT and PET/MRI for their usefulness in detecting and categorizing cervical iodine-positive lesions in patients with differentiated thyroid cancer using (124)I as tracer.

METHODS

The study group comprised 65 patients at high risk of iodine-positive metastasis who underwent PET/CT (low-dose CT scan, PET acquisition time 2 min; PET/CT2) followed by PET/MRI of the neck 24 h after (124)I administration. PET images from both modalities were analysed for the numbers of tracer-positive lesions. Two different acquisition times were used for the comparisons, one matching the PET/CT2 acquisition time (2 min, PET/MRI2) and the other covering the whole MRI scan time (30 min, PET/MRI30). Iodine-positive lesions were categorized as metastasis, thyroid remnant or inconclusive according to their location on the PET/CT images. Morphological information provided by MRI was considered for evaluation of lesions on PET/MRI and for volume information.

RESULTS

PET/MRI2 detected significantly more iodine-positive metastases and thyroid remnants than PET/CT2 (72 vs. 60, p = 0.002, and 100 vs. 80, p = 0.001, respectively), but the numbers of patients with at least one tumour lesion identified were not significantly different (21/65 vs. 17/65 patients). PET/MRI30 tended to detect more PET-positive metastases than PET/MRI2 (88 vs. 72), but the difference was not significant (p = 0.07). Of 21 lesions classified as inconclusive on PET/CT, 5 were assigned to metastasis or thyroid remnant when evaluated by PET/MRI. Volume information was available in 34 % of iodine-positive metastases and 2 % of thyroid remnants on PET/MRI.

CONCLUSIONS

PET/MRI of the neck was found to be superior to PET/CT in detecting iodine-positive lesions. This was attributed to the higher sensitivity of the PET component, Although helpful in some cases, we found no substantial advantage of PET/MRI over PET/CT in categorizing iodine-positive lesions as either metastasis or thyroid remnant. Volume information provided by MRI for some iodine-positive lesions might be useful in dosimetry.

Biochemical Effects of Levothyroxine Withdrawal in Patients with Differentiated Thyroid Cancer

BACKGROUND

Patients with differentiated thyroid carcinoma (DTC) are submitted to withdrawal of levothyroxine (LT4) aftter thyroidectomy, in order to undergo radiodine ((131)I) treatment.

PATIENTS AND METHODS

A total of 345 patients with a history of DTC were enrolled in the study. Their biochemical profile and serum free triiodothyronine (FT3), free thyroxine (FT4) and thyrotropin (TSH) levels were measured during withdrawal of LT4 treatment, and several months after restarting LT4.

RESULTS

During withdrawal, the intra-individual percentage increase in total cholesterol, low density lipoprotein-cholesterol, very low density lipoprotein-cholesterol and triglycerides was of the order of 60-80% and that for high density lipoprotein-cholesterol 30%. Creatinine increased by 30%, whereas Na and K levels decreased by 1%. The increase for creatine phosphate kinase was around 200-300%, for aspartate aminotransferase and alanine aminotransferase 50-80%, for γ-glutamyl transpeptidase 10-20%, and for lactate dehydrogenase 25%. Glucose decreased by 1-4%.

CONCLUSION

Short-term, acute hypothyroidism in patients with DTC induces significant alterations in several biochemical parameters. The presence of other deteriorating diseases should be considered before submitting these patients to LT4 withdrawal.

Individualised dosimetry in patients with differentiated thyroid cancer based on external dose-rate. Optimisation of the number of measurements

OBJECTIVES

To compare the results of individual dosimetry in differentiated thyroid cancer patients treated with (131)I at our centre with the established limits and dosimetry results of published studies. Analysis of the optimal number of measurements necessary to reduce the impact of dosimetry for the comfort of the patient and, secondly, on the workload of health workers.

MATERIAL AND METHODS

Dosimetry was performed in the Nuclear Medicine Department of the University and Polytechnic Hospital La Fe, on 29 patients suffering from differentiated thyroid cancer and treated with activities between 1.02 and 5.51 GBq (mean 2.68 GBq) of (131)I. The Spanish Society of Medical Physics (SEFM) protocol was used, based on measurements of external dose rate adjusted to a bi-exponential curve according to a two compartment model. Different dosimetries were performed on each patient, taking different selections of the available measurements in order to find the optimal number.

RESULTS

Results are well below the dosimetry limits, and are consistent with those obtained in other centres. The number of measurements can be reduced from 5, as proposed in the SEFM protocol, to 4 without significant loss of accuracy. Further reducing measures may be justified in individual cases.

CONCLUSIONS

The values obtained for the dosimetry quantities are significantly below the established limits. A reduction in measurements can be assumed at the cost of a moderate increase in uncertainty, benefiting the patient.

Selectively predictive calcium supplementation using NCCN risk stratification system after thyroidectomy with differentiated thyroid cancer

BACKGROUND

Hypocalcemia is a common complication following thyroidectomy. To explore reasonable and simple methods for predicting postoperative hypocalcemia and identify the optimal strategies for selective calcium supplement are meaningful for surgeon.

METHODS

Based on the NCCN risk stratification system, patients were divided into 4 groups (A-D): low-risk group A, who only underwent limited thyroidectomy (LT) and high-risk groups B, C and D, who had received total thyroidectomy (TT) and selective central and/or lateral neck dissection (SND). After surgery, group C patients were orally given calcium gluconate and group D patients were intravenously given calcium 2 g/day for 7 days, while group B patients did not receive any calcium supplement. Serum calcium and parathyroid hormone (PTH) levels were collected before and after surgery. The incidence of asymptomatic and symptomatic hypocalcemia in each group was recorded.

RESULTS

A total of 132 patients with differentiated thyroid carcinoma (DTC) were included who received surgical treatment. No a significant change was observed in serum calcium and PTH levels in group A, while significant decreases in serum calcium and PTH levels were seen in group B (P < 0.05). Intravenous calcium supplement in group D resulted in a more rapid recovery in serum calcium levels (P < 0.05). The incidences of symptomatic hypocalcemia and asymptomatic hypocalcemia were significantly lower in group A and group D respectively compared to the other groups (All P values < 0.05). In group B, a highest asymptomatic and symptomatic hypocalcemia incidence was detected.

CONCLUSION

Selective calcium supplementation for DTC based on NCCN risk stratification system could be recommended for the high-risk patients.

Evaluation of the clinical value of carbon nanoparticles as lymph node tracer in differentiated thyroid carcinoma requiring reoperation

BACKGROUND

The incidence of parathyroid injury in patients with differentiated thyroid carcinoma (DTC) who underwent reoperation is significantly higher than that incurred from the initial surgery. The aim of this study was to investigate the clinical value of carbon nanoparticles (CN) as tracers for lymph nodes to guide cervical lymph node dissection and protect the parathyroid during reoperation for DTC.

METHODS

Our study recruited 116 patients with DTC who previously underwent thyroidectomy and later received remedial surgical treatment at the Department of Breast and Thyroid Surgery, Hunan Provincial People's Hospital, China, between February 2011 and February 2014. Those patients were randomly divided into the experimental group (the CN group) with 64 cases and the control group with 52 cases. Carbon nanoparticle suspension (CNS, 0.1-0.3 ml) was intraoperatively injected into the residual thyroid or enlarged lymph nodes in the CN group; in the control group, CNS was not applied intraoperatively. The differences in identification of the parathyroid glands, the number of lymph nodes resected intraoperatively, and the incidence of common complications after thyroidectomy in both groups were recorded and analyzed.

RESULTS

The accuracy of identification of the parathyroid in the CN group and control group was 92.2 % and 28.8 %, respectively, and the identification rate of three glands or more in both groups was 75 % and 36.5 %, respectively; those differences were statistically significant between the two groups (P < 0.05). There was also a significant difference between the two groups in the number of lymph nodes removed in the central and lateral cervical compartments (P < 0.05). There was no increase in common complications after the second surgery compared with the previous surgery; in addition, there was a decline in the incidence of transient hypoparathyroidism (HPT) (P < 0.05).

CONCLUSIONS

By tracing the thyroid and cervical regional lymph nodes with carbon nanoparticles, the parathyroid glands can be easily identified and protected to reduce the complications of transient hypoparathyroidism resulting from reoperation for residual or missed DTC. Carbon nanoparticle tracers also facilitate radical resection of lymph nodes at the central and lateral compartments of the neck.

Radioiodine Treatment and Thyroid Hormone Suppression Therapy for Differentiated Thyroid Carcinoma: Adverse Effects Support the Trend toward Less Aggressive Treatment for Low-Risk Patients

Over the past decades, the incidence of differentiated thyroid carcinoma (DTC) has steadily increased, with especially a growing number of low-risk patients. Whereas DTC used to be treated rather aggressively, it is now acknowledged that aggressive treatment does not affect outcome for low-risk patients and that it can induce adverse effects. In this review an overview of the most clinically relevant adverse effects of radioiodine treatment and thyroid hormone suppression therapy (THST) is presented, and the trend toward less aggressive treatment for low-risk patients is outlined. Salivary gland dysfunction occurs in roughly 30% of patients, and is probably due to the concentration of radioiodine in the salivary glands by the sodium/iodide symporter. Beta radiation from radioiodine can result in sialoadenitis and eventually fibrosis and loss of salivary function. Furthermore, patients can experience bone marrow dysfunction following radioiodine treatment. Although this is in general subclinical and transient, patients that receive very high cumulative radioiodine doses may be at risk for more severe bone marrow dysfunction. THST can induce adverse cardiovascular effects in patients with DTC, such as diastolic and systolic dysfunction, and also adverse vascular and prothrombotic effects have been described. Finally, the effects of THST on bone formation and resorption are outlined; especially postmenopausal women with DTC on THST seem to be at risk of bone loss. In the past years, advances have been made in preventing low-risk patients from being overtreated. Improved biomarkers are still needed to further optimize risk stratification and personalize medicine.

Radioiodine Scan Index: A Simplified, Quantitative Treatment Response Parameter for Metastatic Thyroid Carcinoma

PURPOSE

We aimed to develop and validate a simplified, novel quantification method for radioiodine whole-body scans (WBSs) as a predictor for the treatment response in differentiated thyroid carcinoma (DTC) patients with distant metastasis.

METHODS

We retrospectively reviewed serial WBSs after radioiodine treatment from 2008 to 2011 in patients with metastatic DTC. For standardization of TSH simulation, only a subset of patients whose TSH level was fully enhanced (TSH > 80 mU/l) was enrolled. The radioiodine scan index (RSI) was calculated by the ratio of tumor-to-brain uptake. We compared correlations between the RSI and TSH-stimulated serum thyroglobulin (TSH_s_Tg) level and between the RSI and Tg reduction rate of consecutive radioiodine treatments.

RESULTS

A total of 30 rounds of radioiodine treatment for 15 patients were eligible. Tumor histology was 11 papillary and 4 follicular subtypes. The TSH_s_Tg level was mean 980 ng/ml (range, 0.5-11,244). The Tg reduction rate after treatment was a mean of -7 % (range, -90 %-210 %). Mean RSI was 3.02 (range, 0.40-10.97). RSI was positively correlated with the TSH_s_Tg level (R(2) = 0.3084, p = 0.001) and negatively correlated with the Tg reduction rate (R(2) = 0.2993, p = 0.037). The regression equation to predict treatment response was as follows: Tg reduction rate = -14.581 × RSI + 51.183.

CONCLUSIONS

Use of the radioiodine scan index derived from conventional WBS is feasible to reflect the serum Tg level in patients with metastatic DTC, and it may be useful for predicting the biologic treatment response after radioiodine treatment.

[Comparison of differentiated thyroid carcinoma staging systems in a Spanish population]

BACKGROUND AND OBJECTIVE

Differentiated thyroid carcinoma staging is increasingly important due to the current trends to a less intensive therapy in low-risk patients. The TNM system is most widely used, but other systems based on follow-up of several patient cohorts have been developed. When these systems have been applied to other populations, results have been discordant. Our study evaluates the suitability of several differentiated thyroid carcinoma staging systems in a Spanish population.

MATERIAL AND METHOD

729 patients with differentiated thyroid carcinoma and staging data available were enrolled. Mean follow-up time was 10.8 years. The TNM, EORTC, AMES, Clinical class, MACIS, Ohio, NTCTCS, and Spanish systems were applied to all histological types. The Kaplan-Meier survival curves for each system were analyzed, and compared using the proportion of explained variation (PEV).

RESULTS

The demographic and clinical characteristics of our population were similar to those of other Spanish and international cohorts reported. The best systems were NTCTCS, with 74.7% PEV, and TNM (68.3%), followed by the Ohio, MACIS, EORTC, and AMES systems with minimal differences between them, while the least adequate were the Spanish (55.2%) and Clinical class (47.1%) systems.

CONCLUSION

The NTCTCS staging system was found to be better than TNM in our population but, because of its simplicity and greater dissemination, the TNM appears to be recommended for staging of patients with differentiated thyroid carcinoma.

The c.470 T > C CHEK2 missense variant increases the risk of differentiated thyroid carcinoma in the Great Poland population

BACKGROUND

Differentiated thyroid carcinoma (DTC) originates from thyroid follicular epithelial cells and belongs to a group of slowly progressing tumors with a relatively good prognosis. However, recurrences and metastases are a serious problem in advanced stages. Furthermore, progression from a well differentiated thyroid carcinoma to an aggressive anaplastic one is possible. The majority of differentiated thyroid carcinomas are sporadic but a few alleles increasing the cancer risk are known. One of them is the c.470 T > C (p.I157T, rs17879961) missense substitution in the CHEK2 gene.

AIM OF THE STUDY

The aim of this study was to investigate whether this specific CHEK2 alteration, c.470 T > C, predisposes the Great Poland (Wielkopolska) population to thyroid cancer.

METHODS

602 differentiated thyroid carcinoma patients and 829 controls randomly selected from population were genotyped for the presence of the c.470C allele using pyrosequencing. Hardy-Weinberg Equilibrium (HWE) was tested for both groups by chi-square distribution and Fisher's exact test. The odds ratios (ORs), 95% confidence intervals (CIs), and p-values were calculated using the R software.

RESULTS

The results of genotyping showed the presence of the c.470C allele in 51 patients with a frequency of 4.49%, while in a controls in 42 patients with a frequency of 2.53%. We demonstrated that in the Great Poland population the c.470C CHEK2 variant increases the risk of developing differentiated thyroid cancer almost twice (OR = 1.81, p = 0.004). The risk of papillary thyroid carcinoma in female patients homozygous for the c.470C allele was shown to increase almost 13-fold (OR = 12.81, p = 0.019).

CONCLUSIONS

Identification of c.470C CHEK2 gene variant ought to be taken into account by healthcare policymakers. Future well-designed and larger population studies are of great value in confirming these findings. Moreover, a combination of genetic factors together with environmental exposures should also be considered.

Spanish consensus for the management of patients with anaplastic cell thyroid carcinoma

Anaplastic thyroid cancer (ATC) is the most aggressive solid tumour known and is a rare but highly lethal form of thyroid cancer that requires a multidisciplinary team approach. No Spanish consensus exists for management of patients with ATC. The Thyroid Cancer Group of the Spanish Society of Endocrinology and Nutrition and the GETHI (Grupo Español de Enfermedades Huérfanas e Infrecuentes) of the Spanish Society of Oncology, in agreement with the Boards of these Societies, commissioned an independent task force to develop a wide consensus on ATC. The relevant literature was reviewed, including serial PubMed searches supplemented with additional articles. The consensus includes the characteristics, diagnosis, initial evaluation, establishment of treatment goals, approaches to locoregional disease (surgery, radiotherapy, systemic therapy, supportive care during active treatment), approaches to advanced/metastatic disease, palliative care options, monitoring, and long-term follow-up of ATC. For operable disease, a combination of radical surgery with adjuvant radiotherapy or chemotherapy, using agents such as doxorubicin, cisplatin and paclitaxel, is the best treatment strategy. Cytotoxic drugs are poorly effective for advanced/metastatic ATC. On the other hand, targeted agents may represent a viable therapeutic option. Patients with stage IVA/IVB resectable disease have the best prognosis, particularly if a multimodal approach is used, and some stage IVB unresectable patients may respond to aggressive therapy. Patients with stage IVC disease should be considered for clinical trials or for hospice/palliative care depending on their preference. This is the first Spanish consensus for ATC, and provides recommendations for management of this extremely aggressive malignancy. Novel systemic therapies are being tested, and more effective combinations are needed to improve patient outcomes. Although more aggressive radiotherapy has reduced locoregional recurrence, mean overall survival has not improved in the past 50 years.

Is outcome of differentiated thyroid carcinoma influenced by tumor stage at diagnosis?

BACKGROUND

There is no international consensus on surveillance strategies for differentiated thyroid carcinoma (DTC) after radiotherapy for childhood cancer. Ultrasonography could allow for early detection of DTC, however, its value is yet unclear since the prognosis of DTC is excellent. We addressed the evidence for the question: 'is outcome of DTC influenced by tumor stage at diagnosis?'.

METHODS

A multidisciplinary working group answered the sub-questions: 'is recurrence or mortality influenced by DTC stage at diagnosis? Does detection of DTC at an early stage contribute to a decline in adverse events of treatment?' The literature was systematically reviewed, and conclusions were drawn based on the level of evidence (A: high, B: moderate to low, C: very low).

RESULTS

In children, level C evidence was found that detection of DTC at an early stage is associated with lower recurrence and mortality rates. No evidence was found that it influences morbidity rates. In adults, clear evidence was found that less advanced staged DTC is a favorable prognostic factor for recurrence (level B) and mortality (level A). Additionally, it was found that more extensive surgery increases the risk to develop transient hypoparathyroidism (level A) and that higher doses of radioiodine increases the risk to develop second primary malignancies (level B).

CONCLUSION

Identification of DTC at an early stage is beneficial for children (very low level evidence) and adults (moderate to high level evidence), even considering that the overall outcome is excellent. These results are an important cornerstone for the development of guidelines for childhood cancer survivors at risk for DTC.

Preoperative contrast-enhanced computerized tomography should not delay radioiodine ablation in differentiated thyroid carcinoma patients

BACKGROUND

There is concern about potential interference of iodinated contrast used in contrast-enhanced computerized tomography (CECT) with radioiodine therapy in differentiated thyroid carcinoma (DTC). The aim of this study was to determine the effect of iodinated contrast on urinary iodine concentration (UIC) in patients having thyroidectomy compared with control groups without CECT and without thyroidectomy.

METHODS

This prospective control study consisted of 4 groups each comprising 32 patients. Group 1- DTC patients undergoing preoperative CECT, group 2- DTC patients not undergoing CECT, group 3- benign goiter patients undergoing preoperative CECT, and group 4- patients with non-thyroidal diseases undergoing preoperative CECT. Spot UIC before CECT, after surgery (5-7 d), and at follow-up (4-6 wk) were compared among the groups.

RESULTS

The median basal UIC levels were not significantly different between the four groups (232.2 versus 263.9 versus 268.2 versus 178.2 μg/L, respectively, P = 0.443). In contrast, groups having preoperative CECT had significantly higher UIC levels at discharge (924 versus 329 versus 776 versus 661 μg/L, respectively, P = 0.001). These differences became insignificant at follow-up (225 versus 252 versus 310 versus 275 μg/L, respectively, P = 0.505). Patients having follow-up UIC values above the conventional cut-off of clinically relevant iodine excess (>200 μg/L) also had significantly higher basal values than those having lower follow-up values (283.0 versus 181.7 μg/L; P = 0.037).

CONCLUSIONS

Irrespective of the fact whether a patient is thyroidectomized or not preoperative CECT using non-lipophilic contrast does not result in long-term iodine retention.

How to manage patients with differentiated thyroid cancer and a rising serum thyroglobulin level

Serum thyroglobulin (sTg) is the marker for monitoring persistence/recurrence of differentiated thyroid cancer, in patients without sTg antibodies. Patients with undetectable basal sTg or peak sTg <2 ng/mL are cured with low risk to recur. Newly detectable level of sTg indicates the recurrence. The significance of increasing sTg in patients treated with emithyroidectomy or total-thyroidectomy but not ablated with radioiodine is undefined. A doubling time <1 year may be a poor prognostic factor, but this is more relevant in cases with high levels of sTg. Because of its sensitivity, neck ultrasound should be performed at any visit, especially when an increased sTg is seen.

A Logical levothyroxine dose Individualization: Optimization Approach at discharge from Radioiodine therapy ward and during follow-up in patients of Differentiated Thyroid Carcinoma: Balancing the Risk based strategy and the practical issues and challenges: Experience and Views of a large volume referral centre in India

In this communication, the authors discuss the issue of individualization of thyrotropin suppressive therapy in differentiated thyroid carcinoma (DTC) patients and share their views with respect to optimizing the dose of levothyroxine (LT) prescription both during discharge from radioiodine therapy ward and during follow-up. The changing management paradigm at our Institute during post-thyroidectomy period and during the preparation for radioiodine scan is also briefly highlighted. Five factors can be identified as important determinants for the dose individualization approach: (1) Persistence or absence of metastatic disease, (2) the risk characteristics of the patient and the tumor (3) patient's clinical profile, symptomatology, and contraindications (4) the feasibility to ensure a proper thyroid stimulating hormone TSH suppression level (depends on patient's socio-economic and educational background, the connectivity with the local physician and his expertise) (5) time period elapsed since initial diagnosis. While discussing each individual case scenario, the authors, based upon their experience in one of the busiest thyroid cancer referral centers in the country, discuss certain unaddressed points in the current guideline recommendations, deviations made and some challenges toward employing them into practice, which could be situation and center specific. In addition to these, the value of clinical examination, patient profile and detailed enquiry about clinical symptomatology by the attending physician in each follow-up visit cannot be overemphasized. According to the authors, this aspect, quite important for dose determination in an individual, is relatively underrepresented in the present guidelines. It would also be worthwhile to follow a conservative approach (till clear data emerges) in patients who have characteristics of “high-risk” disease, but are clinically and biochemically disease free, if no medical contraindications exist and patient tolerates the suppressive therapy well. This would be particularly applicable in the presence of aggressive histopathological variants, where, in the event of recurrence/metastasis, the disease demonstrates adverse prognosis and higher incidence of radioiodine refractoriness. At the end, certain important and noteworthy concepts pertaining to LT prescription that has definitive practical implications for the suppressive therapy in DTC patients are described.

XRCC1 polymorphisms and differentiated thyroid carcinoma risk: a meta-analysis

The objective of this study is to quantitatively derive a more precise estimation of the association between X-ray repair cross-complementing group 1 (XRCC1) gene polymorphisms and differentiated thyroid carcinoma risk. A comprehensive literature search of three databases was conducted. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with fixed-effect models and random-effect models when appropriate. Overall, no association of the XRCC1 Arg399Gln, Arg280His, and Arg194Trp polymorphisms with differentiated thyroid carcinoma risk was found. In subgroup analyses, a decreased differentiated thyroid carcinoma risk was observed among Caucasians (Gln vs. Arg, OR=0.86, 95% CI=0.77-0.96, P=0.343 for heterogeneity; Gln/Arg vs. Arg/Arg, OR=0.84, 95% CI=0.71-0.98, P=0.229 for heterogeneity; Gln/Gln vs. Arg/Arg, OR=0.77, 95% CI=0.60-0.99, P=0.477 for heterogeneity; dominant genetic model, OR=0.82, 95% CI=0.71-0.95, P=0.272 for heterogeneity), not among Asians. No publication bias was observed. Our results suggest that XRCC1 Arg399Gln polymorphism is not associated with differentiated thyroid carcinoma risk, while a decreased risk is observed among Caucasian population.

Metastatic involvement of the spleen in differentiated carcinoma of thyroid

Splenic metastasis in differentiated thyroid carcinoma is rare occurrence. We describe an unusual case of diffuse metastatic splenic involvement with normal hematological indices in differentiated thyroid carcinoma demonstrated by post-therapy whole body radioiodine scan.

Association of Arg194Trp, Arg280His and Arg399Gln polymorphisms in X-ray repair cross-complementing group 1 gene and risk of differentiated thyroid carcinoma in Iran

BACKGROUND

X-ray repair cross-complementing group 1 (XRCC1) gene is a DNA repair gene and its non-synonymous single nucleotide polymorphisms (SNP) may influence DNA repair capacity which has been considered as a modifying risk factor for cancer development.

METHODS

A case-control study was conducted to investigate impact of three frequently studied polymorphisms (Arg194Trp, Arg280His and Arg399Gln) on developing differentiated thyroid carcinoma (DTC).

RESULTS

Increased risks for DTC were shown in homozygous (odds ratio [OR]: 3.66, 95% confidence interval [CI]: 0.38-35.60) and in dominant trait (OR: 1.22, 95% CI: 1.64-2.32) of Arg194Trp genotype. Also, for Arg280His genotype, an increased risk for DTC was shown in dominant trait (OR: 1.42, 95% confidence interval [CI]: 0.76-2.68), while a mildly reduction of risk for DTC (OR: 0.77, 95% [CI]: 0.50-1.17) was estimated in dominant Gln genotype of Arg399Gln. Considering combinatory effects of Arg194Trp and Arg280His genotypes on DTC, the calculated OR and 95% CI for being heterozygous for one of Arg194Trp or Arg280His genotypes were 1.57 and 0.90-2.74, respectively.

CONCLUSION

Genotyping of codons 194, 280 and 399 in XRCC1 gene may use in risk assessment of DTC.