High Prevalence Of Thyroid Nodules Research Articles

Optimization of iodine intake in Belgium

Mild iodine deficiency (MID) is a long-standing problem in Belgium and was recognized only recently as public health issue by the Ministry of Health (MOH). The main MID-related health problems in Belgium are a high prevalence of thyroid nodules and multinodular goiter. The economic cost of thyroid nodular disease only in Belgium was estimated at about € 40 millions per year. The Belgian health authorities adopted a selective strategy to optimize iodine intake through the fortification of bread with iodized salt. A progressive, step-by-step increase of the iodine content of salt was chosen in order to minimize the incidence of hyperthyroidism. MOH monitors this strategy by assessing periodically the urinary iodine concentration in school-aged children and pregnant women, as well as by a yearly follow-up of TSH concentrations in all Belgian newborns. Although the implementation of this strategy was an important step, the main drawback of the current situation is the absence of a legal framework to support the strategy. The utilization of iodized salt in bread on a voluntary basis was endorsed by the bakery industry and MOH. However a legal framework is required to assure the effectiveness and continuity of the program and to avoid a higher than optimal iodine intake in the population.

Metformin Treatment for Small Benign Thyroid Nodules in Patients with Insulin Resistance

It has been shown that patients with insulin resistance (IR) have a higher prevalence of thyroid nodules and bigger thyroid glands. We evaluated the ability of metformin (M) alone or combined with levothyroxine (L-T₄) to reduce the nodular size in benign thyroid hyperplastic nodules (<2 cm in diameter). A total of 66 women with IR and nodular hyperplasia, diagnosed by fine needle aspiration biopsy (FNAB), who completed this prospective 6-month duration protocol, were assigned to one of four groups: Group I (GI) (n = 14), patients treated with M; GII (n = 18), patients treated with M plus L-T₄; GIII (n = 19), patients treated with L-T₄; and GIV (n = 15), patients without any treatment. All groups of included patients had no statistically significant different mean baseline characteristics. Patients from GII and GIII showed drops in thyroid-stimulating hormone (TSH) levels and GI and GII normalized the homeostasis model assessment (HOMA) index after treatment, as expected. The median baseline size of all included nodules was 298 mm³ ≈0.84 cm in diameter (range, 32-3,616 mm³). After treatment, patients of Group I and II showed significant reductions in their nodule size [median reduction, 108.50 mm³ (30%) and 184.5 mm³ (55%), P < 0.008 and P < 0.0001, respectively]. Patients in GIII and GIV did not have a significant reduction of their nodules [P = not significant (N.S.)]. We conclude that M produced a significant decrease in the nodular size in patients with IR and small thyroid nodules, whereas the combination of M with L-T₄ was the best treatment in these women.

Benefit of measuring basal serum calcitonin to detect medullary thyroid carcinoma in a Danish population with a high prevalence of thyroid nodules

Routine measurement of serum calcitonin to detect medullary thyroid carcinoma (MTC) continues to be fiercely debated, although less attention has been paid to the positive predictive value (PPV) of this method. We collected data from 959 patients with nontoxic nodular goiter; thyroidectomy was performed in 307 of these patients. Thirty-nine patients had elevated serum calcitonin; 6 of these patients had MTC detected by the initial diagnostic setup. No additional patient in the cohort was registered in the Danish Thyroid Cancer Database, reflecting that all patients with MTC were classified correctly initially. The sensitivity of serum calcitonin for detection of MTC was 100%, the specificity was 95.3%, the positive predictive value was 15.4%, and the negative predictive value was 100%. Serum calcitonin has high sensitivity and specificity for detection of MTC. The low PPV might lead to unnecessary thyroid surgery. Thus, the result of serum calcitonin measurement should always be interpreted in the context of other clinical variables.

Birt-Hogg-Dubé syndrome: clinical and genetic studies of 10 French families

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominant genodermatosis predisposing to the development of multiple fibrofolliculomas (FFs), pulmonary cysts, spontaneous pneumothorax and renal neoplasms. The association of BHDS with various nonrenal neoplasms has been reported but remains controversial. To report the clinical features and germline mutations in 22 patients from 10 unrelated families with BHDS investigated during a 5-year prospective study by the Department of Dermatology at the University Hospital of Montpellier, France. Also, to define more clearly the characteristics of pulmonary, thyroid, renal and colorectal manifestations associated with BHDS. Twenty-two patients with clinical and histological criteria of BHDS confirmed by FLCN (previously BHD) germline mutation were evaluated. Lung cysts and pneumothorax were detected by thoracic computed tomography (CT) scanning. Abdominal magnetic resonance imaging (MRI) or CT scans and/or renal ultrasonography were performed to screen for tumours. Thyroid nodules and goitres were assessed by clinical examination, ultrasound imaging and measurement of serum thyroid-stimulating hormone and thyrocalcitonin. Eighteen of the 22 individuals affected by BHDS (82%) were diagnosed with five or more FFs. Multiple epidermal cysts, severe facial hyperseborrhoea and oral papules were noted, respectively, in three of 22 (14%), nine of 22 (41%) and nine of 21 patients (43%). Spontaneous pneumothorax was reported in seven affected patients (32%). Cystic lesions were detected in 14 of 20 patients (70%) and mainly displayed a subpleural and basal location. Renal ultrasound, CT scan and/or MRI revealed renal cysts in 10 patients (45%), without renal carcinoma diagnosed thus far. Thyroid nodules and/or cysts were disclosed by ultrasound examination in 13 of 20 cases (65%). No medullary carcinoma or other thyroid carcinomas were detected. Colonoscopy failed to detect colorectal carcinoma. We report here the largest series to date of French patients with BHDS. We noted a high prevalence of thyroid nodules and renal cysts. However, the lack of a control group does not allow assessment of whether or not such association with BHDS is fortuitous.

Increased Prevalence of Insulin Resistance in Patients With Differentiated Thyroid Carcinoma

Patients with insulin resistance (IR) have a higher prevalence of thyroid nodules. In the present study, we present original data showing that patients with differentiated thyroid carcinoma (DTC) also have a higher frequency of IR. Twenty women with DTC (group 1, G1) and 20 euthyroid individuals (control group, CG) were investigated for IR. G1 and CG subjects were matched in pairs by age, gender, and body mass index (BMI). The diagnosis of IR was made when the homeostasis model assesment of insulin resistance (HOMA-IR) index was higher than 2.5. According to the BMI, 20 women (10 with DTC and 10 of the CG) had a BMI < 25, whereas the other 20 had higher BMI values (overweight and obese patients). IR was present in the 50% of G1, but only in the 10% of the CG (P < 0.001). In the groups with lower BMI (<25), we found IR in 30% of G1 and no cases in the CG, whereas in those with BMI > 25 the IR was present in 70% of G1 and 20% of CG. There were no differences between the two subgroups regarding the time in which the IR tests were performed. IR was present in 56.3% of patient with papillary anol 25% of follicular thyroid carcinomas, respectively. We conclude that such a high prevalence of IR would be an important risk factor for developing DTC, as it is well known with some other nonthyroid carcinomas.

Very high prevalence of thyroid nodules detected by high frequency (13 MHz) ultrasound examination

The prevalence of thyroid nodules in a healthy population is high: in the German Papillon study, nationwide ultrasound screening of more than 90 000 people using 7.5 MHz scanners revealed the presence of thyroid nodules in 33% of the normal population. A study employing more sensitive 13 MHz scanners has not been conducted so far. Six hundred and thirty-five consecutive patients (33% female, 67% male, mean 56.7 years) presenting for a preventive health check up underwent ultrasound screening of the thyroid gland (Siemens Acuson Antares, 13 MHz-linear scanner, B-mode and Power mode) and measurement of the basal TSH (thyroid stimulating hormone) value. Size and degree of vascularization of the thyroid gland and of nodules were determined and analysed retrospectively. In 432 of 635 patients, thyroid nodules could be detected with an increasing incidence with age, in 338 without goiter. Mean thyroid size was 12.3 mL for women and 20.5 mL for men correlating strongly with body weight. Fifty-three percentage of the nodules were smaller than 5 mm. Incidence of thyroid dysfunction was only 4%. No cancerous lesions could be found. Using the 13 MHz technology, we found a substantially higher prevalence of thyroid nodules (68%) than the Papillon study (33%). Even if our population is older than in Papillon, the difference remains in comparable age groups. This is due to the higher sensitivity of 13 MHz scanning. Our study underlines the clinical significance of iodine deficiency and should renew the discussion on routine iodine supplementation.

Thyroid Fine-Needle Aspiration Biopsy: Variability in Reporting

The low incidence of thyroid cancer despite the high prevalence of thyroid nodules necessitates a screening tool to determine which patients require surgical management. The utility of fine-needle aspiration biopsy (FNAB) for this purpose requires a low false-negative (FN) rate and an acceptable sensitivity and specificity for the detection of malignancy. While reviewing our institution's experience with thyroid FNAB, we found significant discrepancies in how statistics of thyroid FNAB were tabulated and reported in the literature. Here we examine the sources of these discrepancies by evaluating large series of thyroid FNAB with regard to cytopathologic reporting and statistical calculation. Published series of thyroid FNAB with >200 FNAB and available histological data with sufficient raw data to recalculate statistics were analyzed. Considering indeterminate and malignant results to be positive FNAB results, since, in a four-tier system, both lead to surgical management, specificity, sensitivity, accuracy, positive predictive value, negative predictive value, FN, and false-positive (FP) rates were recalculated. Differences between reported and recalculated statistics were then evaluated for significance. Nineteen studies and 20 series were identified. The following are reported and recalculated means, respectively: for sensitivity, 81% and 86%; for specificity, 81% and 62%; for accuracy, 77% and 71%; for positive predictive value, 65% and 50%; for negative predictive value, 84% and 93%; for FN rates, 13% and 14%; for FP rates, 10% and 38%. FP rates had a mean of 1.4% when recalculated considering only malignant FNAB as positive tests. Specificity and FP rates had statistically significant differences between the means of reported and recalculated values. Thyroid FNAB remains the screening tool of choice in the evaluation of thyroid nodules. However, the variability in the calculation of reported thyroid FNAB statistics highlights the need for uniformity in statistical reporting for accurate understanding of thyroid FNAB's clinical utility.

A useful ultrasound score to select thyroid nodules requiring fine needle aspiration in an iodine-deficient area

The high prevalence of thyroid nodules in iodine-deficient areas is a practical problem because of the large number of patients requiring fine needle aspiration (FNA) to detect malignant nodules. To obtain an ultrasound (US) score for predicting malignant nodules and reduce the number of unnecessary and expensive FNA. All nodules observed from September 2001 to March 2006 were evaluated by US: echostructure, echogenicity, halo, microcalcifications and ratio between antero-posterior and transversal diameters (AP/TR). Two thousand six hundred and forty-two consecutive patients underwent US-guided FNA for a total of 3645 nodules. Logistic regression analysis showed a potent predictive role for solitary nodules and absence/ incomplete halo (p=0.000). A significant predictive role for microcalcifications and AP/TR ratio was also observed. A 10-point score was constructed using the standardized regression coefficient. Nodules with US score <or=2.4, those between 2.5-5.4 and >or=5.5 had a frequency of malignancy of 0.4, 1.1 and 5.6% (p<0.001), respectively. Nodules with >or=5.5 US score were characterized by a 66% sensitivity and a 76% specificity compared to the diagnostic values of single parameters which were either sensitive or specific. According to our data, we suggest FNA for nodules reaching a >5.4 US score, whereas a clinical judgement should be used for the intermediate category nodules. When the score is lower than 2.5 we do not recommend FNA. The practical use of this US score can help reduce unnecessary and expensive FNA in iodine-deficient areas.

An Ultrasonogram Reporting System for Thyroid Nodules Stratifying Cancer Risk for Clinical Management

There is a high prevalence of thyroid nodules on ultrasonographic (US) examination. However, most of them are benign. US criteria may help to decide cost-effective management. Our objective was to develop a standardized US characterization and reporting data system of thyroid lesions for clinical management: the Thyroid Imaging Reporting and Data System (TIRADS). This was a prospective study using the TIRADS, which is based on the concepts of the Breast Imaging Reporting Data System of the American College of Radiology. A correlation of the US findings and fine needle aspiration biopsy (FNAB) results in 1959 lesions biopsied under US guidance and studied histologically during an 8-yr period was divided into three stages. In the first stage, 10 US patterns were defined. In the second stage, four TIRADS groups were defined according to risk. The percentages of malignancy defined in the Breast Imaging Reporting and Data System were followed: TIRADS 2 (0% malignancy), TIRADS 3 (<5% malignancy), TIRADS 4 (5-80% malignancy), and TIRADS 5 (>80% malignancy). The TIRADS classification was evaluated at the third stage of the study in a sample of 1097 nodules (benign: 703; follicular lesions: 238; and carcinoma: 156). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 88, 49, 49, 88, and 94%, respectively. The ratio of benign to malignant or follicular FNAB results currently is 1.8. The TIRADS has allowed us to improve patient management and cost-effectiveness, avoiding unnecessary FNAB. In addition, we have established standard codes to be used both for radiologists and endocrinologists.

Does Fine-Needle Aspiration Cytology Optimize the Surgical Management of Thyroid Disorders in Endemic Goiter Region?

The aim of this study was to determine the diagnostic value of fine-needle aspiration cytology (FNAC) before thyroidectomy in an endemic goiter region. One hundred patients with preoperative FNAC of thyroid nodules who underwent thyroidectomy were recruited. FNAC were classified into five groups. 0, no thyroid cells; 1, normal thyroid cells; 2, degenerative thyroid cells without evidence of malignacy; 3, follicular or oncocytary neoplasia; and 4, malignant thyroid cells. FNAC was compared with postoperative histopathological diagnoses. Only 76% of the FNAC allowed an adequate cytological examination. In 15 patients (15%), carcinomas were found in the postoperative histopathological diagnosis (including four follicular carcinomas). In the 48 patients of FNAC groups 3 and 4, nine carcinomas (18.7%) were found (including four follicular carcinomas). In the 28 patients of groups 1 and 2, there was only one papillary carcinoma (3.5%). In the 24 patients of group 0, there were two papillary, two follicular, and one anaplastic carcinomas (total of 20.8%). The sensitivity, specificity, and likelihood ratio (LR) of the FNAC for benign nodules were 90%, 40.9%, 0.24, respectively. The LR for malignant nodules was 13.2, and that for follicular neoplasia was 0.55. Despite the high prevalence of carcinoma in an endemic goiter region, FNAC disappointed its diagnostic expectation. The lower specificity of FNAC may be caused by a higher prevalence of thyroid nodules in an endemic goiter region or by the absence of a specialized cytopathologist.

Thyroid Incidentalomas

Background: The prevalence of thyroid nodules in the general population varies according to the method of detection in use. In large population studies, about 5% of subjects have palpable thyroid nodules, while autopsy studies reveal a 49–57% prevalence of thyroid nodules that were asymptomatic during life, and thyroid ultrasonography (US) shows a 13–50% prevalence in the general population. The increased sensitivity of many imaging modalities has led, in turn, to increased detection of subclinical thyroid nodules and of small, nonpalpable incidentalomas, and a diagnostic approach to patients with these nodules is briefly summarized. Conclusions: Despite the high prevalence of thyroid nodules discovered by US, clinically relevant thyroid malignancy remains rare and can be managed conservatively in most cases.

Prevalence of thyroid nodules in an occupationally radiation exposed group: a cross sectional study in an area with mild iodine deficiency

BackgroundThyroid nodules and thyroid cancer occur more frequently in people exposed to radiation for therapeutic purposes, and to nuclear fallout. Furthermore, it is known that a moderate degree of iodine deficiency may be responsible for an increased prevalence of thyroid nodules, while it is suspected that radiation exposure could induce changes in thyroid autoimmunity. The iodine intake of people resident in Bari, S. Italy, is mildly deficient, which could be presumed to cause a higher prevalence of thyroid pathology. This study was conducted to evaluate the prevalence of thyroid nodules in a population occupationally exposed to radiation, in an area of mild iodine deficiency.MethodsA cross-sectional study was designed to evaluate the prevalence of thyroid nodules in radiation exposed workers, compared with a stratified sample of non exposed workers. After giving written consent to participate in the study, all the recruited subjects (304 exposed and 419 non exposed volunteers) were interviewed to fill in an anamnestic questionnaire, and underwent a physical examination, ultrasound thyroid scan, serum determinations of fT3, fT4 and TSH, fine needle aspiration biopsy. The sample was subdivided into one group exposed to a determined quantity of radiation (detected by counter), one group exposed to an undetectable quantity of radiation, and the non exposed control group.ResultsThe prevalence of thyroid nodules <1 cm in diameter, defined as incidentalomas, in the exposed group with detected doses, was 11.28% in males and 9.68% in females, while in the exposed group with undetectable dose the prevalence was 10.39% in males and 16.67% in females. In the non exposed group the prevalence of incidentalomas was 9.34% in males and 13.20% in females. These prevalences were not statistically different when analysed by a multiple test comparison with the bootstrap method and stratification for sex.Instead, the prevalence of thyroid nodules > 1 cm in diameter resulted statistically different in exposed and non exposed health staff: 18.68% in non exposed males vs exposed: 3.76% (determined dose) and 9.09% (undetectable dose) in males, and 20.30% in non exposed females versus 3.23% (detected dose) and 9.52% (undetectable dose) in exposed females.There was a higher proportion of healthy staff in the exposed group than in the non exposed: (80.45% vs 68.68% in males; 80.65% vs 57.87% in females).ConclusionIn our study, occupational exposure to radiation combined with mild iodine deficiency did not increase the risk of developing thyroid nodules. The statistically significant higher prevalence of thyroid nodules in the non exposed group could be explained by the high percentage (22%) of people with a familial history of, and hence a greater predisposition to, thyroid disease.The endemic condition of mild iodine deficiency, demonstrated in other studies, played a major role in determining the thyroid pathology in our study groups.

Thyroid Nodules with Microfollicular Findings Reported on Fine-Needle Aspiration: Invariably Surgical Treatment?

To assess whether fine-needle aspiration (FNA) can be a diagnostic procedure for identification of malignant thyroid nodules when the smear reveals the cytologic (microfollicular) finding of "follicular neoplasm" (FN). We reviewed a group of 79 patients with FN who underwent surgical treatment and evaluated the possible significance of the cytologic features of anisokaryosis, amount of colloid, and nuclear overlapping (NO). We excluded from the study those patients with FN who had other highly suspicious cytologic features, such as sporadic grooves and sporadic pseudonucleoli. In our series of 79 patients with FN at FNA, we found anisokaryosis in 49.4%, scant or no colloid in 31.6%, and NO in 5.1%. Thyroid cancer (TC)--follicular cancer or follicular variant of papillary cancer--was found in six patients (7.6%): four patients (10.2%) with anisokaryosis and two patients (5.0%) without anisokaryosis (P<0.5; chi2 test). All the patients with malignant lesions had scant or no colloid in the smears, and four of them were those with NO. Therefore, TC was found in 24.0% of nodules with scant or no colloid versus 0.0% of nodules with abundant colloid (P<0.001; chi2 test), and TC was found in 100% of nodules with NO versus 2.6% of nodules without NO (P<0.001; chi2 test). Because of the high prevalence of thyroid nodules and the frequency of FN at FNA, the number of unnecessary interventions may be very high. FNA cannot be diagnostic in FN because invasion of the tumor capsule and blood vessels can be evidenced only at histologic examination. Although it is common opinion that microfollicular nodules should be surgically treated, simple cytologic features can help select patients at low risk who can be monitored and reassessed clinically and by FNA. Patients with high-risk cytologic features such as NO should be advised that a total thyroidectomy may be necessary.

Influence of frequency of previous pregnancies on the prevalence of thyroid nodules in women without clinical evidence of thyroid disease.

In a region with insufficient alimentary iodine supply (Kiel, Northern Germany) the prevalence of thyroid nodules was studied by means of ultrasonography in 212 healthy women (36-50 years old) in four groups of 53 women each with 0, 1, 2, and 3-5 previous pregnancies. Goiters were found in 28.3% (15 of 53) of the women without children and in 28.9% (46 of 159) of the women with children. There was no significant increase of goiter prevalence according to the number of pregnancies. We detected thyroid nodules in 21.2% (45 of 212). Only 9.4% (5 of 53) of the women without previous pregnancies had thyroid nodules, but 25.1% (40 of 159) of the women with pregnancies in the past had nodules, the difference being statistically significant (p < 0.05). We observed nodules in 11 of 53 women with 1 child (20.7%), in 11 of 53 women with 2 children (20.7%), and in 18 of 53 women with 3-5 previous pregnancies (33.9%). We propose that, in regions with borderline or insufficient alimentary iodine supply, accentuated iodine deficiency during pregnancies due to increase of iodine requirement is a probable cause for the higher prevalence of thyroid nodules in women with previous pregnancies.