Risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy in thyroid nodules with diameters greater than 4 centimeters

Objective

The risk of malignancy and diagnostic accuracy of fine-needle aspiration biopsy (FNAB) of thyroid nodules (TN) with diameters ≥ 3-4 cm remains controversial. However, some groups have indicated surgical treatment in these patients regardless of the FNAB results. We aimed to evaluate the diagnostic accuracy of the FNAB in systematically resected ≥4 cm TN and if the risk of malignancy is higher in these patients.

Subjects and methods

We retrospectively evaluated 138 patients (142 nodules) with TN with diameters ≥4 cm who underwent thyroidectomy.

Results

The FNAB results were nondiagnostic/unsatisfactory (ND/UNS) in 2.1% of the cases and benign in 51.4%. They indicated atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in 23.9% of cases, follicular neoplasia/suspicious for a follicular neoplasm (FN/SFN) in 9.2%, suspicion of malignancy (SUS) in 8.5%, and malignant in 4.9%. The histopathological analysis after thyroidectomy revealed a thyroid cancer rate of 100% in the FNABs classified as malignant, 33.3% in SUS cases, 7.7% in FN/SFN, 17.6% in AUS/FLUS, and 4.1% in benign FNABs. None of the ND/UNS FNABs were malignant. The global malignancy diagnosis was 14.8% (n = 21). However, the rate of false negatives for FNAB was low (4.1%).

Conclusion

We showed that the risk of malignancy in nodules with diameters ≥4 cm was higher compared to the risk of thyroid cancer in TN in general. However, we found a low rate of false-negative cytological results; therefore, our data do not justify the orientation of routine resection for these larger nodules.

Clinical impact of thyroglobulin (Tg) and Tg autoantibody (TgAb) measurements in needle washouts of neck lymph node biopsies in the management of patients with papillary thyroid carcinoma

Objectives

The presence of thyroglobulin (Tg) in needle washouts of fine needle aspiration biopsy (Tg-FNAB) in neck lymph nodes (LNs) suspected of metastasis has become a cornerstone in the follow-up of patients with papillary thyroid carcinoma (PTC). However, there are limited data regarding the measurement of anti-Tg antibodies in these washouts (TgAb-FNAB), and it is not clear whether these antibodies interfere with the assessment of Tg-FNAB or whether there are other factors that would more consistently justify the finding of low Tg-FNAB in metastatic LNs.

Materials and methods

We investigated 232 FNAB samples obtained from suspicious neck LNs of 144 PTC patients. These samples were divided according to the patient's serum TgAb status: sTgAb- (n = 203 samples) and sTgAb+ (n = 29). The TgAb-FNAB levels were measured using two different assays. Tg-FNAB was also measured using two assays when low levels (< 10 ng/mL) were identified in the first assay of the metastatic LNs from the sTgAb+ samples.

Results

The TgAb-FNAB results were negative in both assays in all samples. Low levels of Tg-FNAB were identified in 11/16 of the metastatic LNs of the sTgAb+ patients and 16/63 of the sTgAb- patients (p < 0.05) using assay 1. The measurement of the Tg-FNAB levels using assay 2 indicated additional metastases in 5 LNs of the sTgAb+ patients.

Conclusions

Factors other than the presence of TgAb-FNAB may contribute to the higher number of metastatic LNs with undetectable Tg-FNAB in the sTgAb+ group. In addition, the measurement of Tg-FNAB using different assays was useful to enhance the diagnosis of metastatic LNs, particularly when cytological and Tg-FNAB results are discordant.

A Prospective Study Showing an Excellent Response of Patients with Low-Risk Differentiated Thyroid Cancer Who Did Not Undergo Radioiodine Remnant Ablation after Total Thyroidectomy

OBJECTIVES

To prospectively evaluate the outcome of patients with low-risk papillary thyroid carcinoma treated with total thyroidectomy (TT) who did not undergo radioiodine remnant ablation (RRA).

STUDY DESIGN

We prospectively followed up 57 patients; 3 months after TT, thyroglobulin (Tg) assessment and neck ultrasonography (US) were performed while patients were taking l-T4, presenting suppressed TSH. Six months after TT, patients underwent stimulated Tg testing and whole-body scan (WBS) after recombinant TSH (rhTSH). Then, 18 months after TT, the patients were evaluated by neck US and Tg under TSH between 0.5 and 2.0 mIU/ml. Two years after TT, we performed another rhTSH assessment, measuring Tg and making a WBS. The patients were then annually monitored with neck US and Tg measurement under TSH between 0.5 and 2.0 mIU/l for 36-84 months.

RESULTS

Neck US of all patients, 3 months after TT, presented no evidence of abnormal residual tissues or metastatic lymph nodes (negative neck US); at this time, the mean Tg level was 0.42 ng/ml. Six months after surgery, after rhTSH, the mean thyroid bed uptake was 1.82%, and Tg levels ranged from 0.10 to 22.30 ng/ml (mean, 2.89 ng/ml). The patients were followed up without any sign of recurrence (negative neck US and stable or decreasing Tg levels). During the ongoing follow-up, the Tg trend was stable or decreasing, independently of the initial suppressed or stimulated Tg level, or WBS uptake.

CONCLUSIONS

In patients with low-risk differentiated thyroid cancer, who were operated by TT and who did not undergo RRA, an excellent response to treatment may be confirmed by annual neck US and Tg trend.

Basal serum thyroglobulin measured by a second-generation assay is equivalent to stimulated thyroglobulin in identifying metastases in patients with differentiated thyroid cancer with low or intermediate risk of recurrence

BACKGROUND

Guidelines for the follow-up of differentiated thyroid cancer (DTC) recommend the measurement of TSH-stimulated thyroglobulin (s-Tg) instead of basal Tg on T4 therapy (b-Tg). However, these guidelines were established using first-generation Tg assays with a functional sensitivity (FS) of 0.5-1.0 ng/ml. Current more sensitive second-generation Tg assays (Tg2G; FS 0.05-0.10 ng/ml) have shown that low-risk DTC patients with undetectable b-Tg rarely have recurrences.

OBJECTIVES

This study was undertaken to compare b-Tg using a chemiluminescent Tg2G assay (Tg2GICMA; FS 0.1 ng/ml) with s-Tg in DTC patients with an intermediate risk of recurrence.

METHODS

We evaluated 168 DTC patients with a low (n = 101) and intermediate (n = 67) risk of recurrence treated by total thyroidectomy (147 also treated with radioiodine), with a mean follow-up of 5 years.

RESULTS

b-Tg was undetectable with the Tg2GICMA in 142 of 168 patients. s-Tg was <2 ng/ml in 138 of these 142 patients, and only 3 of these 138 (2%) presented metastases on cervical ultrasound (US). Of the 4 of 142 patients with s-Tg >2 ng/ml, 1 had cervical metastases seen after radioiodine. Furthermore, 26 of 168 patients presented detectable b-Tg with the Tg2GICMA; 17 of these 26 patients also presented s-Tg >2 ng/ml. In 10 of these 17 patients, metastases were detected. Cervical US or b-Tg were positive in 14 of 15 patients with recurrent disease. Globally, the sensitivity and negative predictive value of the Tg2GICMA plus US were 93 and 99%, respectively.

CONCLUSION

b-Tg measured with a Tg2GICMA and cervical US, used together, are equivalent to s-Tg in identifying metastases in patients with DTC with a low or intermediate risk of recurrence.

Development of a sensitive and specific quantitative reverse transcription-polymerase chain reaction assay for blood thyroglobulin messenger ribonucleic acid in the follow-up of patients with differentiated thyroid carcinoma

CONTEXT

Serum thyroglobulin is a sensitive tumor marker in the follow-up of patients with differentiated thyroid carcinoma (DTC), but the presence of endogenous anti-thyroglobulin antibodies (TgAb) can interfere on its measurement. To prevent interference by TgAb, several investigators have tried to quantify blood mRNA Tg by real-time RT-PCR, but the results have been variable, not reporting a correlation between mRNA Tg and the presence of metastases.

OBJECTIVE

The aim of the study was to evaluate the development of a sensitive and specific quantitative RT-PCR assay for blood mRNA Tg in the follow-up of patients with DTC.

DESIGN AND PATIENTS

An assay employing primers located in a region not affected by alternative splicing or single nucleotide polymorphisms was developed to study 104 DTC patients (13 of 104 with positive TgAb).

RESULTS

The assay is specific for thyroid tissue because we found mRNA Tg expression in normal thyroid tissue, but we did not find any mRNA Tg expression in any extrathyroidal tissues. Quantitative mRNA Tg levels were significantly different between patients "free of disease" (82 of 104) and those with metastases (22 of 104) (2.61 +/- 0.26 vs. 27.58 +/- 1.62 pg mRNA Tg/microg RNA) (P < 0.0001). A cutoff point of 5.51 was able to discriminate between the two groups. In addition, the measurement of mRNA Tg was not affected by the presence of TgAb.

CONCLUSION

This new mRNA Tg quantification is a reliable method that allowed us to differentiate patients free of disease from those with metastases, and it could represent an appropriate molecular marker for the follow-up of patients with DTC, especially those with positive TgAb.

Diagnóstico de metástases de carcinoma papilífero de tiróide através da dosagem de tiroglobulina no líquido obtido da lavagem da agulha utilizada na punção aspirativa

Com a introdução da ultra-sonografia cervical (USC) no seguimento dos pacientes com carcinoma papilífero de tiróide (CPT), tornou-se freqüente o encontro de pequenos linfonodos (LNs) cervicais. Porém, apesar de a USC apresentar alta sensibilidade, o estudo citológico obtido por punção aspirativa (PAAF) e, nos últimos anos, a dosagem da tiroglobulina (Tg) no lavado da agulha da PAAF (Tg-PAAF) vêm assumindo papel importante no diagnóstico de LNs cervicais. O objetivo deste estudo é verificar a acurácia da combinação da USC, citologia e Tg-PAAF em LNs suspeitos. Estudamos 32 pacientes que apresentavam 44 LNs à USC, classificados como "inflamatórios" (19) ou "suspeitos" (25). Dos 25 LNs suspeitos, 15 apresentavam Tg-PAAF elevada (13 com citologia compatível com metástases e 2 com citologia não-diagnóstica). Esses 15 LNs (11 pacientes) foram confirmados como metástase de CP pelo exame histopatológico. Os 19 LNs "inflamatórios" e os 10/25 LNs "suspeitos" apresentaram citologia negativa e Tg-PAAF indetectável. Concluímos que a USC apresenta alta sensibilidade na detecção de linfonodos cervicais, porém citologia e dosagem de Tg-PAAF são fundamentais para o diagnóstico. A associação USC, citologia e Tg-PAAF pode ser considerada a abordagem mais sensível e específica na detecção de LNs metastáticos em pacientes com CPT.

[Incidence of malignant lesions in patients with clinically benign thyroid nodules: observational and prospective study in a cohort of 50 patients followed during two years]

INTRODUCTION

To study the frequency of malignant lesions in patients with clinically benign thyroid nodules and the value of the repetition of fine needle aspiration biopsy (FNAB).

METHODS

Observational and prospective 2-year study in a cohort of 50 patients with clinically benign thyroid nodules. Patients were initially submitted to clinical examination, ultrasound (US) and FNAB1 patients, followed by a second FNAB and US.

RESULTS

Palpation is not a good test for diagnosis and follow-up of thyroid nodules. On the other hand, the initial consideration that these patients should harbor benign lesions is a very useful parameter, since 47/50 patients (94%) did not present malignant lesions during the follow-up. FNAB1 and FNAB2 were concordant in 33/39 patients when FNAB1 was negative (85%); 11 patients were operated, 8 by suspicious FNAB and 3 due to nodule growth. We observed 2 patients with non-invasive papillary microcarcinoma and 1 patient with papillary carcinoma outside of the main nodules.

CONCLUSION

there was concordance between initial clinical benign diagnosis, FNAB and the follow-up. In one case there was a papillary carcinoma. In addition, ultrasonography should be considered for all patients with suspected thyroid nodules. Finally, we demonstrated that a second cytology usually confirms the result of the first cytology in benign thyroid nodules.

Injeção percutânea de etanol no tratamento de nódulos tiroidianos sólidos, císticos e autônomos

A injeção percutânea de etanol (IPE) guiada por ultra-som tem sido utilizada para o tratamento de nódulos tiroidianos autônomos, sólidos e císticos. Apresentamos nossa experiência em 50 pacientes tratados, sendo 26 portadores de nódulos sólidos, 17 de nódulos císticos e 7 de nódulos autônomos (NA). Avaliamos os pacientes 1 semana, 1 mês, 3 meses, 6 meses e 1 ano após a IPE. Após 1 ano, os nódulos sólidos reduziram a 74% do volume inicial, os císticos diminuíram 92% sem apresentar recidivas. Um ano após o tratamento dos nódulos autônomos, 5 pacientes estavam em eutiroidismo clínico e laboratorial e 2 em eutiroidismo mas com TSH subnormal. Não houve recorrência da tirotoxicose e a redução nodular foi de 66%. O procedimento foi bem tolerado por todos. Os resultados confirmam que a IPE é uma boa alternativa terapêutica para redução dos nódulos tiroidianos císticos e sólidos e no tratamento dos nódulos autônomos.