Thyroid Nodule Size Research Articles

Risk of Malignancy in Follicular Neoplasms without Nuclear Atypia: Statistical Analysis of 397 Thyroidectomies

To determine how to triage patients with a follicular neoplasm (FN), without nuclear atypia reported by fine-needle aspiration, on the basis of risk factors. The age, sex, tumor size, and cell type of 397 patients who underwent thyroidectomy for follicular carcinoma (FC) or follicular adenoma between 1991 and 2001 were analyzed statistically. The likelihood ratio and probability of FC for various combinations of tumor size, sex, and cell type were estimated with use of Bayes' theorem. FC was significantly associated with tumor size >2.1 cm (P = 0.048), male sex (P = 0.0007), and Hürthle cell type (P<0.0001). The mean size of minimally invasive FC was significantly smaller (2.9 cm versus 4.8 cm; P = 0.004) and the mean patient age was significantly younger (47.6 years versus 61.0 years; P = 0.003) than for widely invasive FC. The lowest probability (0.31%) for FC was in female patients with a small (< or = 2.1 cm) micro-follicular FN reported by a cytopathology practice with 10% accuracy of true FN at surgical intervention, whereas the highest probability (29.5%) for FC was in male patients with a large (>2.1 cm) Hürthle cell neoplasm reported by a cytopathology practice with 70% accuracy of true FN at surgical intervention. Although an estimate of probability for FC based on age, sex, thyroid nodule size, and cell type is provided in this study for patients diagnosed with FN without nuclear atypia on fine-needle aspiration, the variability of the accuracy in cytopathology practice makes it difficult to change the current treatment paradigm, which requires carefully planned prospective studies with long-term follow-up.

Changes in both size and cytological features of thyroid nodule after levothyroxine treatment.

We prospectively evaluated the effects of 12 months thyrotropin suppressive levo-thyroxine (L-T4) therapy in terms of changes in both thyroid nodule size and cytological features and considered whether thyroid nodule size changes actually resulted in (or were the result of) cytological changes. We studied 142 consecutive patients with benign 'cold' solitary thyroid nodules. For the purposes of the study, we divided our patients into three groups according to their initial cytological nodule classification as follows: group 1, including 88 colloid nodules (CN); group 2, including 30 hyperplastic nodules (HN); and group 3, including 24 adenomatous nodules (AN). The effects of TSH suppressive L-T4 treatment on both nodule volume and cytological characteristics were evaluated by ultrasonography and fine-needle aspiration (FNA) before and 12 months after the onset of therapy. Twelve months of TSH suppressive L-T4 treatment were effective in shrinking about one-third to one-quarter (31.8% CN, 26.7% HN and 25% AN) of thyroid nodules, irrespective of their initial cytological characteristics. Similarly, there was no difference in the prevalence of 'non-responders' (increasing nodules) to L-T4, which accounted for about one-fifth or less (20.5% CN, 13.3% HN and 20.8% AN) of all nodules. We found also that cytological features changed in 33.8% nodules after 12 months of L-T4 treatment. These changes were most commonly observed in HN and AN and consisted largely ( approximately 80%) of cytological characteristics resembling colloid features, not only in shrinking but also in stable nodules, thus indicating that cytology changes might be the very first indicator of nodule sensitivity to L-T4 therapy even in the continued absence of nodule shrinkage. When nodules were divided into three subgroups according to variations in size (shrinking, stable and increasing nodules), we observed that the distribution of the three cytological types showed a trend towards colloid lesions in shrinking nodules (chi2 3.8, P < 0.005) and towards an augmentation of hypercellular, adenomatous and suspicious characteristics in increasing nodules (chi2 3.6, P < 0.005). The frequency of shrinking nodules was not different between colloid, hyperplastic and adenomatous nodules. Repeat FNA should be advisable for thyroid nodules which increase in volume despite L-T4 therapy and might also provide useful information about nodule sensitivity to L-T4 treatment for both HN and AN, even where nodule size remains stable.

The effect of pregnancy on thyroid nodule formation.

Epidemiology data have revealed a higher prevalence of nodular goiters in women than men in both iodine-sufficient and iodine-deficient areas. Increased prevalence of thyroid nodules has also been reported in women with higher gravidity. However, the association between pregnancy and thyroid nodule formation has never been studied. The aim of our study was to evaluate the incidence of thyroid nodules during pregnancy and determine whether pregnancy will induce thyroid nodule formation. Two hundred twenty-one healthy southern Chinese women in the first trimester of their pregnancy were studied prospectively. Thyroid ultrasonography, thyroid function tests, and urinary iodine excretion were measured at first, second, and third trimesters of pregnancy as well as 6 wk and 3 months postpartum. Thyroid nodules (>2 mm in any dimension on ultrasonography) were detected in 34 (15.3%) subjects at first trimester, with 12 (5.4%) subjects having more than one nodule. Eight subjects had clinically palpable nodules. Women with thyroid nodules were older (P < 0.01) and had higher gravidity (P < 0.02) than those women without thyroid nodules. The volume of the single/dominant nodules increased from 60 (14--344) mm(3), median (interquartile range) at first trimester to 65 (26-472) mm(3) at third trimester (P < 0.02). These nodules remained enlarged at 103 (25-461) mm(3) 6 wk postpartum (P < 0.005) and 73 (22-344) mm(3) at 3 months postpartum (P < 0.05). Patients with thyroid nodules had lower serum TSH values (P < 0.03) and higher Tg levels (P < 0.05) throughout pregnancy. Appearance of new nodules was detected in 25 (11.3%) women as pregnancy advanced so that by 3 months postpartum, the incidence of thyroid nodular disease was 24.4% (P < 0.02 vs. first trimester). Compared with those with no detectable nodules throughout pregnancy, subjects with new nodule formation had higher urinary iodine excretion from second trimester onward (P all < 0.05). However, no difference could be detected in their TSH and Tg levels throughout pregnancy. Fine-needle aspiration on nodules greater than 5 mm in any dimension after delivery (n = 21) confirmed the majority having histological features consistent with nodular hyperplasia. No thyroid malignancy was detected. In conclusion, pregnancy is associated with an increase in the size of preexisting thyroid nodules as well as new thyroid nodule formation. This may predispose to multinodular goiter in later life.

THE EFFECT OF ENDOGENOUS TSH-SUPPRESSION THERAPY

This investigation was undertaken to clarify the effectiveness of endogenous TSH-suppression therapy with thyroxin (T4) for adenomatous goiter (AG) employing ultrasonography. Seventeen AG patients treated with T4 (50-100μg daily) during the past 7 years were enrolled in the present study. Serum TSH level of the all patients were continuously suppressed under 0.2μU/ml. Sixteen patients with AG only being followed-up periodically without suppression therapy during the same period, were served as control for the purpose of comparison. Ultrasonographical examination was carried out every 3-6 months. According to the change in the size of main thyroid nodule, all these patients were classified into 3 types as follows: D; apparent decrease more than 5mm in diameter of the nodule, I; increase of the nodule size more than 5mm, and NC; no significant change in diameter of the nodule. In the 17 patients having the TSH-suppression therapy with T4, D-type, I-type and NC type were noted in 3, 4 and 10 patients, respectively. Meanwhile, in the 16 control patients, three types were found in 3, 6, and 7 patients, respectively. There exist no significant differences in change of the main nodule size between the two groups. This clinical study indicates that endogenous TSH-suppression therapy for AG would not be effective.

Large cystic/solid thyroid nodules: a potential false-negative fine-needle aspiration.

False-negative fine-needle aspiration (FNA) biopsy results of thyroid nodules are of particular concern because they imply missed malignant lesions. The purpose of this study was to identify characteristics of thyroid nodules that may lead to false-negative cytologic interpretation after FNA. We reviewed 90 consecutive patients who underwent preoperative FNA of thyroid nodules followed by thyroid surgery during a period of 27 months, including their clinical data, type and size of thyroid nodule, FNA cytology results, and final pathology report of the surgical specimen. Thyroid nodules that had the highest probability of malignancy were those that were large (3 cm or larger), cystic/solid, or large and cystic/solid. The overall false-negative rate for preoperative FNA was 11%. Large, cystic/solid, and thyroid nodules with both characteristics had false-negative rates of 17%, 25%, and 30%, respectively, compared with 0%, 9%, and 17% for small (less than 3 cm), solid, and solid nodules 3 cm or larger, respectively. Because of the high prevalence of malignancy in thyroid nodules that are large (3 cm or larger), cystic/solid, or large and cystic/solid and the high false-negative rate of FNA in diagnosing these lesions, thyroid lobectomy for diagnosis should be strongly considered in these patients even when FNA cytologic finding is interpreted as benign.

Thyroid hormone suppressive therapy of sporadic nontoxic goiter.

Thyroid hormone has been used to reduce the size of sporadic nontoxic goiter since 1894. Noncontrolled clinical studies suggest that about two thirds of goiters respond to therapy, and a recent randomized clinical trial confirms the efficacy of suppressive therapy for sporadic nontoxic goiter. Efficacy is at least partly correlated with suppression of pituitary TSH production, response is usually evident by 3 months, relapse occurs when therapy is withdrawn, and nodular goiters may be less responsive than diffuse goiters. Some, but not all, series suggest that postoperative use of thyroid hormone suppressive therapy prevents recurrence of benign goiter. Three recent randomized trials suggest that thyroid hormone administered for 6 months to 3 years does not reduce the size of solitary thyroid nodules. About one third of nodules regressed in both treatment and placebo groups. Long-term studies are needed to define the effects of thyroid hormone suppressive therapy on the growth of goitrous lesions based on their underlying pathophysiology.

Pregnancy in Patients with Mild Thyroid Abnormalities: Maternal and Neonatal Repercussions*

A prospective study was undertaken during pregnancy in 120 euthyroid women presenting with mild thyroid abnormalities (TA): 11 with a past history of thyroid disorder, 44 with goiter, 20 with nodules, and 45 with thyroid autoantibodies. The aims of the study were to assess whether the pattern of thyroid alterations during gestation was different in women with TA compared to that in healthy control pregnant subjects and to evaluate possible obstetrical and neonatal repercussions. The overall prevalence of underlying subtle thyroid abnormalities in the cohort was 17%, probably as the result of the environmental moderately low iodine intake. Despite the intrinsic heterogeneity of the four groups of women with TA, the adaptation of the thyroid to the stress of pregnancy was different from that of the control subjects. Noteworthy were 1) the marked elevation of serum thyroglobulin in women with past history of thyroid disorder, goiter and thyroid nodules; 2) the increase in goiter size in a third of the goitrous women, associated with biochemical evidence of functional stimulation of the gland; 3) the indirect evidence of partial thyroidal autonomy in goitrous patients; and 4) the increase in the number and size of thyroid nodules during gestation. Taken together, the data indicated that pregnancy was associated with a greater thyroidal risk in patients with TA compared to healthy subjects. In relation to thyroid autoimmunity, most patients remained euthyroid during gestation, but in a few cases, TSH was elevated at delivery, suggesting diminished thyroidal reserve. Also, 40% of newborns from mothers with thyroid autoimmunity had elevated thyroid peroxidase antibody titers at birth, and there was a highly significant correlation between maternal and neonatal thyroid peroxidase antibody titers. Finally, thyroid autoimmunity was clearly associated with an increased risk of spontaneous abortion (13.3 vs. 3.3%; P less than 0.001). Thyroid function in newborns from mothers with TA was normal and not different from that in controls; similarly, obstetrical features were similar in patients with TA and control subjects. In conclusion, pregnancy is associated with a greater thyroidal risk in women with TA, thereby emphasizing a potential link between pregnancy and thyroid disorders. It is recommended that patients with known, even subtle, thyroid abnormalities be closely monitored during pregnancy, in particular those with a goiter, nodules, or thyroid autoimmunity, especially in areas with a moderately low iodine intake, where the prevalence of mild thyroid disturbances is high.

Thyroxine for Six Months Does Not Reduce Thyroid Nodule Size

Thyroxine for Six Months Does Not Reduce Thyroid Nodule Size

Proceedings: Thyroid suppression.

Routine thyroid suppression with administration of exogenous thyroid hormone has altered management of thyroid nodules. During 22 years the mean number of thyroid operations per year in our hospital declined from 68.3 to 18.5, while the proportion of cancer cases in those operated on rose from 4% to 36.5%. The operative mortality in 1,009 thyroidectomies was zero. In the last ten years, 54 patients have had surgical removal of thyroid cancer. Only two of these have died of tumor. That a decrease in size of malignant thyroid nodules was recorded in four patients on suppression is evidence that this technique does not prevent progression of thyroid cancer. Thyroid suppression is beneficial in selection of patients for operation. If this approach is to be used routinely however, strict adherence to absolute and relative criteria for surgery must be employed by both internist and surgeon.

Postoperative thromboses in hemophilia B.

Postoperative thromboses in hemophilia B.