Malignancy risk for thyroid nodules larger than 4 cm and diagnostic reliability of ultrasound-guided FNAB results

The Utility of ACR TI-RADS in Predicting False-Negative Fine Needle Aspiration for Thyroid Cancer

BACKGROUND

Thyroid nodule fine needle aspiration (FNA) biopsies are associated with a low false-negative rate. There is limited data regarding the predictive value of American College of Radiology Thyroid Imaging Reporting and Data System for false-negative FNA.

METHODS

This single-center retrospective study evaluated 119 patients who underwent thyroidectomy. The association of TR category, along with other clinical variables, with false-negative FNA was evaluated.

RESULTS

The overall false-negative rate of FNA was 10.8% (n = 9). False-negative FNAs were associated with younger age (mean 42 years vs 50.6 years, P = .04), larger nodule size (mean 4.4 cm vs 3.2 cm, P = .03), and a lower TR category (median 3 v 4, P = .01).

DISCUSSION

Lower TR category, younger age, and larger nodule size were associated with false-negative FNA of thyroid nodules. These findings should be taken into context when counseling patients with thyroid nodules who have a benign FNA.

Quantitative evaluation of diffusion-weighted MRI for differentiating benign and malignant thyroid nodules larger than 4 cm

PURPOSE

Our study aimed to diagnose benign or malignant thyroid nodules larger than 4 cm using quantitative diffusion-weighted imaging (DWI) analysis.

METHODS

Eighty-two thyroid nodules were investigated retrospectively and divided them into benign (n = 62) and malignant groups (n = 20). We calculated quantitative features DWI and apparent diffusion coefficient (ADC) signal intensity standard deviation (DWISD and ADCSD), DWI and ADC signal intensity ratio (DWISIR and ADCSIR), mean ADC and minimum ADC value (ADCmean and ADCmin) and ADC value standard deviation (ADCVSD). Univariate and multivariate logistic regression were conducted to identify independent predictors, and develop a prediction model. We performed receiver operating characteristic (ROC) analysis to determine the optimal threshold of risk factors, and constructed combined threshold models. Our study calculated diagnostic performance including area under the ROC curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and unnecessary biopsy rate of all models were calculated and compared them with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) result.

RESULTS

Two independent predictors of malignant nodules were identified by multivariate analysis: DWISIR (P = 0.007) and ADCmin (P < 0.001). The AUCs for multivariate prediction model, combined DWISIR and ADCmin thresholds model, combined DWISIR and ADCSIR thresholds model and ACR-TIRADS were 0.946 (0.896-0.996), 0.875 (0.759-0.991), 0.777 (0.648-0.907) and 0.722 (0.588-0.857). The combined DWISIR and ADCmin threshold model had the lowest unnecessary biopsy rate of 0%, compared with 56.3% for ACR-TIRADS.

CONCLUSION

Quantitative DWI demonstrated favorable malignant thyroid nodule diagnostic efficacy. The combined DWISIR and ADCmin thresholds model significantly reduced the unnecessary biopsy rate.

Concordance of the ACR TI-RADS Classification With Bethesda Scoring and Histopathology Risk Stratification of Thyroid Nodules

Importance

Although most thyroid nodules are benign, 10% to 15% of them harbor cancer. Thyroid ultrasonography is useful for risk stratification of nodules, and American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) classification provides recommendations for fine-needle aspiration cytology (FNAC) based on objective ultrasonographic features of these nodules.

Objective

To validate the concordance of ACR TI-RADS classification with Bethesda classification and histopathology.

Design, Setting, and Participants

This retrospective cohort study was performed to evaluate the concordance of ACR TI-RADS classification with Bethesda classification and histopathology and was conducted in Singapore General Hospital Outpatient Otolaryngology clinic in March 2021 to May 2021. Data analysis was performed in May 2021.

Main Outcomes and Measures

Results were deemed concordant when ACR TI-RADS recommendations aligned with Bethesda scores. Conversely, results were classified as nonconcordant with Bethesda scores and/or histopathology results when nodules that were recommended for FNAC yielded benign results or nodules that were not recommended for FNAC yielded malignant results.

Results

A total of 446 patients (370 women [83%]; mean [range] age, 60 [24-89] years) who underwent ultrasonography of the thyroid and ultrasonography-guided thyroid FNACs were identified. A total of 492 of 630 nodules (78.1%) were benign on FNAC (Bethesda II). Score 3 ACR TI-RADS nodules yielded the highest negative predictive values: 94.6% (95% CI, 92.9%-95.9%; P < .001) compared with Bethesda scoring and 100.0% (95% CI, 15.8%-100.0%; P = .003) compared with histopathology. Score 4 or 5 ACR TI-RADS nodules yielded positive predictive values of 2.8% and 16.2%, respectively, compared with Bethesda scoring and 6.1% and 66.7%, respectively, compared with histopathology. Small (<1.5 cm) ACR TI-RADS nodules of scores of 4 and 5 that were not recommended for FNAC yielded a malignant risk of 5.7% and 25.0% on Bethesda 5 and 6, respectively. On surgical excision, 5 of 46 (10.9%) ACR TI-RADS 4 nodules and 15 of 21 (71.4%) of ACR TI-RADS 5 nodules were confirmed to be malignant. Among nodules initially not recommended for FNAC, histopathology-proven cancer was found in 4 of 13 (30.7%) and 3 of 6 (50.0%) of nodules, respectively.

Conclusions and Relevance

These findings suggest that ACR TI-RADS score 3 nodules have a low risk of cancer and should be considered for FNAC only if nodules are 2.5 cm or larger. Patients with small (<1.5 cm) ACR TI-RADS 4 and 5 nodules should be appropriately counseled for FNAC to exclude cancer.

Comparative analysis of accuracy between fine-needle aspiration biopsy and postoperative histopathology for detecting large thyroid nodules: A retrospective observational study

To avoid unnecessary surgeries, ultrasound-guided fine-needle aspiration biopsy (FNAB) is an effective and reliable procedure for the preoperative evaluation of thyroid nodules. However, there have been only a limited number of studies exploring the ability of preoperative FNAB to distinguish malignancy compared to postoperative histopathology in thyroid nodules larger than 4 cm. The aim of this study was to investigate the diagnostic accuracy of FNAB compared to postoperative histopathology in distinguishing malignancy in thyroid nodules larger than 4 cm. A single-center retrospective observational study was conducted at Dr. Zainoel Abidin Hospital, Banda Aceh, Indonesia, between January 2014 and December 2018. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated. A total of 83 patients were included in the study. The results showed that preoperative FNAB may have the ability to distinguish malignancy compared to postoperative histopathology. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 42.85%, 98.38%, 90.00%, 83.56%, and 84.33%, respectively. These data suggested that ultrasound-guided preoperative FNAB is a reliable diagnostic tool in the preoperative evaluation of thyroid nodules larger than 4 cm, but it has limited capability in distinguishing malignancies. In conclusion, although FNAB may be useful in reducing unnecessary surgeries, histopathology remains the preferred method for confirming malignancy in thyroid nodules.

Preoperative evaluation of thyroid nodules - Diagnosis and management strategies

Thyroid cancer is the most common endocrine malignancy, with increasing incidence over the past few decades. Fine needle aspiration (FNA) biopsy is the gold standard for preoperative diagnosis of thyroid malignancies. Nevertheless, this method renders indeterminate results in up to 30% of the cases. Therefore, these patients are often referred to unnecessary surgery to establish the diagnosis. To improve the accuracy of preoperative diagnosis, several other ways, such as ultrasonography, elastography, immunohistochemical analysis, genetic testing, and core needle biopsy, have been developed and can be used either in association with or as an alternative to FNA. This review aims to evaluate all these diagnostic tools to determine the most appropriate way of managing thyroid nodules and subsequently improve the selection of cases referred to surgery.

Preoperative prediction of lymph node metastasis in patients with papillary thyroid carcinoma by an artificial intelligence algorithm

BACKGROUND

It is necessary to identify patients at risk of developing lymph node metastasis prior to papillary thyroid carcinoma (PTC) surgery. This can be challenging due to limiting factors, and an artificial intelligence algorithm may be a viable option.

OBJECTIVE

In this study, we aimed to evaluate whether combining an artificial intelligence algorithm (support vector machine and probabilistic neural network) and clinico-pathologic data can preoperatively predict lymph node metastasis of papillary thyroid carcinoma (PTC).

METHODS

We retrospectively examined 251 PTCs with lymph node metastasis and 194 PTCs without lymph node metastasis. The artificial intelligence algorithm included the support vector machine (SVM) and the probabilistic neural network (PNN).

RESULTS

The ACR TI-RADS (Thyroid Imaging, Reporting and Data System), number of tumours, no well-defined margin, lymph node status and rim calcification on ultrasonography (US), age, sex, tumour size, and presence of Hashimoto's thyroiditis were significantly more frequent among PTCs with central lymph node metastasis than those without metastasis (P<0.05). The PNN classifier revealed an F1 score of 0.88 on the central lymph node metastasis test set. The SVM classifier revealed an F1 score of 0.93 on the lateral lymph node metastasis test set. Our study demonstrates that combining artificial intelligence algorithms and clinico-pathologic data can effectively predict the lymph node metastasis of papillary thyroid carcinoma prior to surgery.

False positive cases in thyroid cytopathology - the experience of a single laboratory and a systematic review

INTRODUCTION

Fine needle aspiration (FNA) is fundamental in the pre-operative assessment of thyroid nodules. However, the shining success of thyroid FNA is occasionally eclipsed by false positive (FP) cytological diagnoses. We describe our experience regarding FP cytological diagnoses and present a literature review concerning FP rates.

MATERIALS AND METHODS

We retrospectively analyzed 2031 consecutive cytology reports. FP was defined as a case with "suspicious for malignancy" or "malignant" cytology, whose surgical follow-up failed to confirm the initial diagnosis of malignancy. We used the PubMed database for the literature review using specific search terms ("thyroid", "cytology", "false positive").

RESULTS

Out of 2031 FNA reports, 93 cases with "suspicious for malignancy" or "malignant" cytology underwent surgical excision. Histopathology did not confirm malignancy in 10 cases (0.6% FP rate). Nodules with FP cytology were significantly larger (P = 0.0024) than those with with TP (true positive) cytology. A review of 25 publications shows comparable results to ours with some slight differences. The majority of studies achieve a FP rate below 3%. Most FP cytological diagnoses turn out to be non-neoplastic lesions (nodular hyperplasia, adenomatous nodule, lymphocytic thyroiditis), which combined account for 80.5% of all histological diagnoses.

CONCLUSIONS

Thyroid nodules with FP cytology were larger than nodules with TP cytology. Most studies manage to adhere to the recommended FP rates, or values close to them, with some outliers. Nevertheless, the mean FP rate values are very close to the value recommended by The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The FP rate value depends on how one defines true negative cases, which can be either histologically proven benign cases, via a benign clinical course, or by assuming that cytologically benign cases remain as such.

The comparison of the histopathological results of the thyroid fine-needle aspiration biopsies in the 795 patients with thyroidectomy

BACKGROUND

We aimed to evaluate the effectiveness of preoperative fine-needle aspiration biopsies (FNAB) by the postthyroidectomy pathology results.

METHOD

Seven hundred and ninety-five patients with FNAB and following thyroid operations which have been performed between April 2008 and December 2019 were included in this study. By comparing the results of the FNAB and final pathologies, the specificity, sensitivity, FNR, false positivity ratio (FPR), accuracy and also the effect of nodule diameter on these have been evaluated. In Bethesda III subgroup according to FNAB, we investigated the malignancy rates and in whom this risk has been increased more.

RESULTS

In our study, the sensitivity of FNAB is 73.40%, the specificity is 95.33%, the accuracy is 91.81%, FNR is 26.60% and FPR is 4.67%. In the patients with nodules ≥4 cm and < 4 cm respectively, we calculated the sensitivity 20.0% vs 79.76%, specificity 95.73% vs 95.19%, accuracy 89.82% vs 92.78%, FNR 80.0% vs 20.24%, FPR 4.27% vs 4.8%.

CONCLUSION

Thyroid FNAB is an easy procedure with a high specificity and sensitivity. Nevertheless, when the nodule diameter was ≥4 cm, increased FNR and decreased sensitivity should be kept in mind while evaluating the patients.

Comparison of diagnostic accuracy of ACR-TIRADS, American Thyroid Association (ATA), and EU-TIRADS guidelines in detecting thyroid malignancy

PURPOSE

This study aims to compare three guidelines according to their diagnostic accuracy in the management of thyroid nodules.

METHODS

A total of 540 patients with 597 thyroid nodules were enrolled in this study. Sonographic images were classified and scored with the American Thyroid Association (ATA-2015), American College of Radiology (ACR), and European Thyroid Association (EU) Thyroid Imaging, Reporting, and Data Systems (ACR-TIRADS and EU-TIRADS) guidelines. Fine-needle aspiration biopsy (FNAB) was performed, and cytopathological results were reported with the Bethesda system. Outcomes of these three classification systems were then correlated with Bethesda results.

RESULTS

FNAB procedures revealed a total of 447 benign and 45 malignant nodules. With guideline dedicated FNAB criteria; 38 malignant nodules could have been diagnosed with ATA-2015, which is followed by 34 nodules with ACR-TIRADS, and 31 nodules with EU-TIRADS. Nonetheless, 301 benign nodules would have been biopsied with ATA-2015, 143 benign nodules with ACR-TIRADS, 222 benign nodules with EU-TIRADS. The accuracy rate was found to be highest with ACR-TIRADS (59.93 %); while 55.20 % with ATA-2015 and 51.25 % with EU-TIRADS. The sensitivity and specificity ratios of these guidelines were as follows; ATA-2015 (82.22, 53.47), ACR-TIRADS (48.89, 60.63), and EU-TIRADS (86.67, 48.99). A total of 23 nodules (3.8 %) could not be classified with ATA-2015.

CONCLUSION

Diagnostic strengths, unnecessary recommended FNAB rates, and categorization capabilities differ among various guidelines. Clinicians and interventional radiologists should keep in mind these features in the management of thyroid nodules.