Accuracy of fine-needle aspiration biopsy for predicting neoplasm or carcinoma in thyroid nodules 4 cm or larger

Are there predictors of malignancy in patients with multinodular goiter?

BACKGROUND

Multinodular goiters (MNG) have recently been shown to have an incidence of cancer that approaches that of solitary thyroid nodule. However, fine needle aspiration (FNA) of a MNG is limited due to the presence of multiple nodules. Therefore we sought to identify risk factors for malignancy in patients with MNG.

METHODS

A total of 1791 consecutive patients underwent thyroidectomy at a single academic institution between May 1994 and December 2009. Of these, 838 patients had a MNG, which we defined as ≥ 2 nodules on preoperative ultrasound. The medical records of these patients were reviewed and analyzed.

RESULTS

A final pathologic diagnosis of malignancy was found in 260 of 838 (31%) of MNG patients. Of the 260 patients with malignancy, 113 (44%) had a focus of cancer <1 cm. Of the patients with malignancy on final pathology, preoperative FNA detected only 46% (n = 120). Of the 140 cancers not recognized preoperatively, 61 (44%) were >1 cm in size. On univariate analysis risk factors for malignancy were younger age and male gender. Patients with malignant nodules also had smaller nodules, smaller thyroids, and fewer nodules than those patients with benign findings on pathology. On multivariate analysis all predictors remained independently associated with malignancy with the exception of thyroid weight.

CONCLUSION

Risk factors for malignancy in a MNG included male gender, younger age, fewer nodules, and smaller nodule size. The low predictive value of FNA in our population suggests there needs to be better ways to predict malignancy in patients with MNG. Therefore, these clinical risk factors should be considered when consulting patients with MNG in regards to their risk of malignancy.

Surgeon-performed ultrasound can predict benignity in thyroid nodules

BACKGROUND

Surgeon-performed ultrasound (SUS) has become an extension of the physical examination in the evaluation of patients with thyroid nodules. Amid concerns that too many "diagnostic" thyroidectomies are performed, this study examines the usefulness of SUS in predicting benign thyroid nodules.

METHODS

A retrospective review of 624 patients with solitary or dominant thyroid nodules and prospectively collected data of SUS nodule features before thyroidectomy (benign = 407; malignant = 217) was performed. A specific model for statistical analysis was created to predict benignity.

RESULTS

Significant predictors of benignity by SUS after logistic regression included isoechogenicity, cystic component, no microcalcifications, regular borders, and size <1 cm. The resultant specificity of this reduced model was 97.6% with a 10.6% sensitivity for predicting benign pathology. After excluding patients with lesions >4 cm or a history of thyroid cancer, thyroid nodules measuring 1-4 cm with the presence of the 4 other criteria by SUS was 98.5% specific for the detection of benign pathology (1.5% false-negative rate).

CONCLUSION

Approximately 10% of thyroidectomy patients had benign nodules that were 1-4 cm, isoechoic, with regular borders, had a cystic component, and no microcalcifications by SUS. Patients without clinical risk factors and these SUS features may safely forego further fine needle aspiration and thyroid lobectomy, and can be monitored with serial ultrasound examinations.

The diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy and the sonographic differences between benign and malignant thyroid nodules 3 cm or larger

BACKGROUND

Although fine-needle aspiration biopsy (FNAB) is considered the standard for preoperative evaluation of thyroid nodules, the value of this has been questioned for large thyroid nodules. Here, we evaluated the diagnostic accuracy of ultrasound-guided FNAB (US-FNAB) for thyroid nodules that were 3 cm or larger as well as the sonographic differences between benign and malignant nodules in this size group.

MATERIALS AND METHODS

There were 661 thyroid masses equal to or larger than 3 cm who underwent US-FNAB from February 2002 to December 2006 and were included in this study. The cytology and surgical pathology readings in these patients were reviewed along with the ultrasonography features, the last from the retrospective review by one radiologist. Histopathology was used to calculate accuracy parameters for the US-FNAB cytology readings. In addition, the likely diagnoses for patients with a benign cytology reading were ascertained.

RESULTS

Thyroid surgery was performed for 206 of the 661 nodules in the same number of patients (31.2%). All subjects who had inadequate, indeterminate, or suspicious for malignancy cytology readings had thyroid surgery. All of the patients who did not have thyroid surgery were considered likely to have benign disease because of their initial cytology reading and follow-up, and finally, 587 (88.8%) were benign and 74 (11.2%) were malignant. When considering malignant, suspicious for malignancy, and indeterminate cytology readings as positive and benign cytology as negative, the sensitivity was 96.7%, specificity 85.9%, positive predictive value 76.6%, negative predictive value 98.2%, and accuracy 89.4%. Ultrasonography features of malignancy were more prevalent in thyroid nodules that were malignant compared with those that were benign or considered likely to be benign (70.3% vs. 1.2%, p < 0.001), and ultrasonography features of a benign nodule were more prevalent in thyroid nodules that were benign or considered likely to be benign than those that were malignant (94.9% vs. 29.7%, p < 0.001).

CONCLUSION

In this study, US-FNAB appeared to be a relatively accurate method to evaluate thyroid nodules larger than 3 cm, with false-negative rates of about 2%. Much larger series would be required to determine its utility in this setting.

The use of the Bethesda terminology in thyroid fine-needle aspiration results in a lower rate of surgery for nonmalignant nodules: a report from a reference center in Turkey

The Bethesda system (BS) for reporting thyroid fine-needle aspiration (FNA), which classifies nodules as nondiagnostic (ND), benign (B), atypia/follicular lesion of undetermined significance (AUS/FLUS), suspicious for follicular neoplasm (SFN/FN), suspicious for malignancy (SFM), or malignant (M), uses clinically valuable management guidelines. The authors employed a similar in-house classification system (IS) for thyroid FNAs, using the categories of ND, B, suspicious follicular cells (SFC), follicular lesion/neoplasm (FL/FN), SFM, and M. The authors compared IS and BS, and assessed the utility of BS in clinical practice. A total of 581 nodules with cytological/histological follow-up were examined and indeterminate lesions by BS were reclassified. The sensitivity and specificity for malignancy using IS were similar to that of BS (77% vs 99%). However, when SFN/FN and SFM were both considered positive, the results for IS and BS were as follows: sensitivity, 85% versus 85%; specificity, 87% versus 94%; and diagnostic accuracy, 86% versus 90%, respectively. Discrepancies between cytological and histological data were evident in 35 cases among all categories of BS except AUS/FLUS. The rate of surgery for nonmalignant nodules was lesser (20% vs 9%) by BS. Among 34 AUS/FLUS cases with follow-up data, hypocellularity was the case in 11 (46%) nonneoplastic and 10 (100%) neoplastic nodules. The use of BS results in a lower rate of surgery for nonmalignant nodules even though patients with borderline cytopathologic features are still encountered. AUS/FLUS category can be separated into subgroups according to the factors causing difficulties in the interpretation. There is a need of accumulation of AUS/FLUS cases to do further evaluations and studies.

Fine needle aspiration of the thyroid: a contemporary experience of 3981 cases

BACKGROUND

Fine needle aspiration (FNA) is an essential tool for the management of thyroid nodules. Recently, several national organizations have recommended FNA of all thyroid nodules >1 cm. With the increase use of imaging in the practice of medicine over the last decade, the number of incidentally discovered thyroid nodules is rising. Therefore, we analyzed our experience to determine if these changes in practice led to alterations in the population of patients undergoing FNA at our institution.

MATERIALS AND METHODS

Data were collected from 981 consecutive patients who underwent thyroid FNA at our institution between 2002 and 2009. Patients were divided in two groups: the early time period 2002-2005 (group 1) and later time period 2006-2009 (group 2). Data from the two groups were analyzed with t-test and χ(2) tests (SPSS, Inc., Chicago, IL).

RESULTS

Comparing the groups, the number of FNAs performed in the later time period increased significantly by 250%. Patients in the later time period (group 2) were more likely to be female and were significantly older. With regard to FNA diagnoses, the number of benign FNAs increased, while the percentage of FNAs diagnosed as malignant and as follicular neoplasm decreased. There also appears to be an increase in the incidence of thyroiditis.

CONCLUSIONS

The use of thyroid FNA has markedly increased during this contemporary series. This rise in thyroid FNA appears to be due to biopsy of benign thyroid nodules. With time, more females and older patients have undergone FNA, possibly reflecting the increased use of imaging studies in this patient population.

Inadequate cytology in thyroid nodules: should we repeat aspiration or follow-up?

BACKGROUND

To evaluate how to correctly manage thyroid nodules showing inadequate cytology after ultrasound (US)-guided fine-needle aspiration biopsy (US-FNAB).

MATERIALS AND METHODS

A total of 393 thyroid nodules with inadequate cytology in 351 patients (M:F = 40:311, mean age: 49.3 years) with surgery or follow-up US-FNAB for at least 1 year were included in this study. Among them, 293 (74.6%) were benign and 100 (25.4%) were malignant on final reference results. Clinical characteristics and US features were reviewed and compared.

RESULTS

Malignancy rates (39.5%) of nodules having suspicious US feature were significantly higher than those (10.9%) of nodules without any suspicious US feature (P < .001). Malignancy rates of solid nodules, mainly solid nodules, and mainly cystic nodules were 29.2, 16.7, and 9.5%, respectively, with significant differences (P = .016). Malignancy rates of nodules assessed as suspicious malignant to probably benign in composition are: 39.1-12.8% (P < .001) in solid nodules, 42.1-9.2% (P = .001) in mainly solid nodules, and 50.0-5.3% (P = .04) in mainly cystic nodules.

CONCLUSIONS

In nodules with inadequate cytology, follow-up US can be considered over repeat aspiration if there are no suspicious US features present, especially in mainly cystic nodules.

Is a five-category reporting scheme for thyroid fine needle aspiration cytology accurate? Experience of over 18,000 FNAs reported at the same institution during 1998-2007

OBJECTIVE

Fine needle aspiration (FNA) has long been recognized as an essential technique for the evaluation of thyroid nodules. Although specific cytological patterns have been recognized, a wide variety of reporting schemes for thyroid FNA results have been adopted. This study reports our experience with a five-category reporting scheme developed in-house based on a numeric score and applied to a large series of consecutive thyroid FNAs. It focuses mainly on the accuracy of thyroid FNA as a preoperative test in a large subset of histologically distinct thyroid lesions.

METHODS

During the 1998-2007 period, 18,359 thyroid ultrasound-guided FNAs were performed on 15,269 patients; FNA reports were classified according to a C1-C5 reporting scheme: non-diagnostic (C1), benign (C2), indeterminate (C3), suspicious (C4), and malignant (C5).

RESULTS

Non-diagnostic (C1) and indeterminate (C3) FNA results totalled 2,230 (12.1%) and 1,461 (7.9%), respectively, while suspicious (C4) and malignant (C5) results totalled 238 (1.3%) and 531 (2.9%), respectively. Histological results were available in 2,047 patients, with thyroid malignancy detected in 840. Positive predictive value of FNA was 98.1% with a 49.0 likelihood ratio (LR) of malignancy in patients with a C4/C5 FNA report.

CONCLUSIONS

This five-category scheme for thyroid FNA is accurate in discriminating between the virtual certainty of malignancy associated with C5, a high rate (92%) of malignancy associated with C4, and a 98% probability of a histological benign diagnosis associated with C2. Further sub-classifications of C3 may improve the accuracy of the diagnostic scheme and may help in recognizing patients eligible for a 'wait and see' management.

Low false-negative rate of cytology in thyroid nodules > 4 cm

OBJECTIVE: To report the results of cytology and histology obtained for a series of systematically resected thyroid nodules > 4 cm. METHODS: A group of 151 patients with thyroid nodules > 4 cm was submitted to surgery despite the cytology result. RESULTS: Malignancy was confirmed histologically in 22.5% of the patients. Excluding cases of insufficient material, cytology was benign in only 3/31 carcinomas (90.3% sensitivity). The frequency of malignancy was 35% among nodules with indeterminate cytology (follicular neoplasm), and there was a predominance (77%) of papillary carcinoma. The negative predictive value of benign cytology was 96.4%. CONCLUSIONS: The false-negative rate of cytology in thyroid nodules > 4 cm does not justify systematic resection of these nodules in asymptomatic patients with benign cytology.

Clinical efficacy of fine-needle aspiration biopsy of thyroid nodules in males

BACKGROUND

It has recently been suggested that the use of fine-needle aspiration (FNA) biopsy of thyroid nodules in male patients is associated with an unacceptably high false-negative rate in the detection of thyroid malignancy. We hypothesize that FNA biopsy is an accurate preoperative tool for detecting thyroid cancer in men, and that false negative rates are significantly lower than recently reported.

MATERIALS AND METHODS

A retrospective database analysis was performed on all male patients who underwent thyroid surgery from May 1994 through January 2007 at a single institution. The results of preoperative FNA biopsies were compared with final surgical pathologic results. FNA biopsy results were reported as benign, malignant, inconclusive (i.e., follicular neoplasm), or nondiagnostic; final surgical pathology was reported as benign or malignant.

RESULTS

Of 1205 patients who underwent thyroidectomy, 273 (23%) were male. Preoperative FNA biopsy results were obtained in 60% of these male patients and were read as benign in 45/165 (27%) patients, malignant in 47/165 (28%) patients, inconclusive in 66/165 (40%) patients, and nondiagnostic in 7/165 (4%) patients. In male patients with cytology reported as benign, 3/45 (6.7%) FNAs were determined to be malignant on final pathology.

CONCLUSIONS

Our study determined that FNA biopsy of thyroid nodules in male patients has an acceptably low false-negative rate of 6.7% and is, therefore, an accurate and useful diagnostic tool. We recommend preoperative FNA biopsy for all male patients presenting with thyroid nodules as a standard of practice.