Surgical Treatment of Solitary Thyroid Nodules Via Fine-Needle Aspiration Biopsy and Frozen-Section Analysis

Utility of Routine Frozen Section of Thyroid Nodules Classified as Follicular Neoplasm

OBJECTIVES

To evaluate the diagnostic performance of frozen section in thyroid nodules classified as follicular neoplasm.

METHODS

A diagnostic test meta-analysis was designed. Studies that assessed frozen section in patients with thyroid nodules and a fine-needle aspiration biopsy result of Bethesda IV were selected. The outcomes measured were the number of false- and true-positive and -negative results. We used the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) instrument for methodological quality assessment and a bivariate mixed-effects regression framework and a likelihood-based estimation of the exact binomial approach.

RESULTS

Forty-six studies from 1991 to 2018 were included. Most studies had moderate methodological quality. The overall sensitivity and specificity were 43% (95% confidence internal [CI], 0.34-0.53) and 100% (95% CI, 0.99-1.00), respectively. The hierarchic summary receiver operating characteristic curve showed an area under the curve of 0.91 (95% CI, 0.80-0.97).

CONCLUSIONS

Frozen section demonstrates moderate diagnostic performance in patients with follicular neoplasm, and its utility for making intraoperative decisions is limited. Its routine use should be discouraged.

18FDG-positron emission tomography/computed tomography (PET/CT) scanning in thyroid nodules with nondiagnostic cytology

OBJECTIVE

To assess the role of positron emission tomography/computed tomography (PET/CT) scans with (18) FDG ((18)FDG-PET/CT) in the evaluation of thyroid nodules with nondiagnostic cytology.

SUBJECTS AND METHODS

Eighty-eight patients with a single euthyroid nodule and repeatedly nondiagnostic ultrasound-guided fine-needle cytology (US-FNC) were enrolled in the present study. Nodules concentrating (18)FDG were considered positive (i.e. suspicious for malignancy). Histological findings were obtained after surgery in all patients.

RESULTS

None of 41 patients with negative (18)FDG-PET/CT scan had a final histological diagnosis of malignancy (i.e. no false-negative results). Twenty-nine patients with final histological diagnosis of thyroid cancer had positive (18)FDG-PET/CT scan. Eighteen patients with final histological diagnosis of benign lesions (including four with follicular adenomas) also had positive (18)FDG-PET/CT scans. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 100%, 69%, 79%, 62% and 100%, respectively.

CONCLUSIONS

A negative (18)FDG-PET/CT scan accurately excludes malignancy in thyroid nodules with non-diagnostic US-FNC procedures. Histology is still necessary to distinguish benign from malignant disease in (18)FDG-PET/CT-positive nodules, but unnecessary surgery could have been reduced from 88 to 41 cases (46%) in our series.

Application of pattern analysis in fine needle aspiration of solitary nodule of thyroid

BACKGROUND

Various methods are used to arrive at a conclusive diagnosis of thyroid lesions on fine needle aspiration cytology (FNAC). Systemic pattern analysis is one such that can be used to analyze the lesions and divide them into individual categories.

AIMS

To study the application of pattern analysis in the interpretation of solitary thyroid nodule (STN).

MATERIALS AND METHODS

Two hundred and nineteen cases of fine needle aspiration cytology of STN were reviewed along with histopathological correlation. Smears were classified based on primary and secondary patterns. Predominant pattern (primary) was identified and lesion categorized. This was followed by identifying the next dominant pattern (secondary) and recategorization. Cytological diagnosis based on primary and secondary patterns was correlated with the histopathological diagnosis.

RESULTS

Based on pattern analysis, the study had a sensitivity of 66.7% and specificity of 98.9%. The positive predictive value and negative predictive value were 88.9% and 96% respectively and the overall diagnostic accuracy was 95.4%.

CONCLUSIONS

The present study demonstrates the feasibility and applicability of pattern analysis in diagnosing thyroid lesions by FNAC, which could be easily reproducible.

(99m)Tc-sestamibi scanning in thyroid nodules with nondiagnostic cytology

BACKGROUND

Our aim in this study was to assess the relevance of (99m)Tc-sestaMIBI (MIBI) scan in the diagnostic evaluation of thyroid nodules with nondiagnostic cytology.

METHODS

In all, 74 patients with a single nodule and repeatedly nondiagnostic ultrasound-guided fine-needle aspiration cytology (US-FNAC) were enrolled. In all cases thyroid nodules were cold in (99m)Tc-pertechnetate (Tc) scans. Thyroid scans were also acquired 30 and 120 minutes after intravenous administration of MIBI. Nodules that concentrate MIBI were considered as positive (ie, suspicious for malignancy). Histologic findings were obtained after surgery in all patients.

RESULTS

No differences occurred in early and late MIBI images. None of 63 patients with a negative MIBI scan had a final histologic diagnosis of malignancy (ie, no false-negative results). Two patients with a final histologic diagnosis of papillary thyroid carcinoma (PTC) and 1 with follicular thyroid carcinoma (FTC) had a positive MIBI scan. Eight patients with a final histologic diagnosis of benign lesions (3 with follicular adenomas) also had MIBI-positive scans. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were, respectively, 100%, 88%, 89%, 27%, and 100%.

CONCLUSIONS

A negative MIBI scan in a cold nodule accurately excludes malignancy when US-FNAC is reported as nondiagnostic. This avoids the need for more invasive diagnostic procedures (ie, surgery) and positively influences the cost-effectiveness profile. A MIBI scan may be performed by acquiring images 30 minutes after tracer administration alone. Histology is still necessary to distinguish benign from malignant disease in a MIBI-positive nodule but unnecessary surgery could have been reduced from 71 to 8 cases in our series.

A meta-analysis of comparing fine-needle aspiration and frozen section for evaluating thyroid nodules

The literature on comparing fine-needle aspiration (FNA) and frozen section for evaluating thyroid nodules was reviewed. Publications on this subject were divided into three groups (follicular lesions, non-follicular lesions and thyroid lesions, not otherwise specified). A meta-analysis was done to compare sensitivity, specificity, and positive and negative predictive values between FNA and frozen section diagnoses. For follicular lesions, FNA was much more sensitive but less specific, with lower positive predictive value than frozen section. FNA and frozen section are virtually identical in all parameters of accuracy in evaluating thyroid nodules that are not follicular lesions. The third group of publications that did not separate/specify follicular lesions from non-follicular lesions was non-contributory.

Thyroid fine-needle aspiration biopsy: variability in reporting

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Fine-needle aspiration biopsy of benign thyroid nodules: an evidence-based review

BACKGROUND

Since the development of fine-needle aspiration biopsy (FNAB) techniques, preoperative diagnosis and subsequent strategies for patient treatment have changed and evolved greatly. This is true also for thyroid FNAB: the vast majority of thyroid nodules are benign, and hence do not necessarily require surgical treatment.

METHODS

A comprehensive Medline and Cochrane Library search was performed evaluating FNAB in the thyroid. In the last decade more than 400 articles on the subject have been published. Data in relation to the experience with FNAB at the Karolinska University Hospital since its introduction were also reviewed.

RESULTS

The development of FNAB since the 1960s at the Karolinska University Hospital is described. During the period 1992-1996 the accuracy of the clinical routine was evaluated by studying the outcomes of almost 4,000 FNAs of the thyroid. The results were good, with only a few false-negative and false-positive results, but the problem of differentiating follicular adenoma from follicular carcinoma remained a significant problem. The use of immunological analysis has greatly increased the possibility of obtaining valuable information on cellular characteristics.

CONCLUSION

A successful FNAB service rests on several factors, and the importance of clinical conferences between all specialists involved in the diagnosis and treatment of patients with thyroid disorders cannot be overemphasized. At the Karolinska University Hospital there are weekly conferences where patients are discussed both pre- and postoperatively. These conferences lead to optimal interaction between the different specialists and, most important, substantial improvement in the clinical management of patients with thyroid disorders.

Immunohistochemical staining for thyroid peroxidase (TPO) of needle core biopsies in the diagnosis of scintigraphically cold thyroid nodules

BACKGROUND

Cold thyroid nodules are common, in particular in iodine-deficient areas, but only a minority of them are malignant requiring surgery. Thyroid peroxidase (TPO) immunostaining of fine-needle aspiration cytology (FNAC) material has proven helpful in diagnosing cells from malignant lesions, but the procedure has its limitations in a routine setting.

PURPOSE

To improve diagnosis and reduce surgery rate, the FNAC procedure was replaced by needle core biopsy (NCB), which was routinely stained for TPO by the monoclonal antibody mAb 47.

MATERIALS AND METHODS

During a 5-year period 427 consecutive patients with a cold thyroid nodule were evaluated by ultrasound-guided NCB, which had been routinely stained for TPO in an automated immunostainer. Sensitivity and specificity and predictive values of the TPO immunostaining were estimated, based on the final diagnosis obtained from surgical resection.

RESULTS

The majority of nodules with benign NCB diagnosis were not surgically removed, and thus a subgroup of 140 operated nodules formed the basis for the calculations. Sensitivity and specificity for benign and malignant lesions were 100% if the oxyphilic variant of adenomas and minimally invasive follicular carcinomas were excluded. By inclusion of these, the values fell to 89% and 97%, respectively. The predictive value of a positive test was 96% and the predictive value of a negative test was 97%.

CONCLUSION

TPO immunostaining was found to be a valuable adjunct to morphology in the diagnosis of cold thyroid nodules of the nonoxyphilic type.

An updated audit of fine needle aspiration cytology procedure of solitary thyroid nodule

This study was conducted to see the sensitivity, specificity, and accuracy of fine needle aspiration cytology (FNAC) for solitary thyroid nodules and to compare our experience with that of other regions of the world. It was a prospective cross sectional study conducted on 76 thyroid samples submitted and reported at the Department of Pathology, King Edward Medical University, Lahore. There were 65 (85.5%) females and 11 (14.5%) males. Male to female ratio was 1:5.9. Ages of the patients ranged from 10 to 60 year with mean age 35.37 +/- 12.17. Thirty-three (43.42%) samples were indeterminate. There were 30 cases (39.47%) of benign lesions, comprising of colloid goiter, follicular adenoma, and diffuse hyperplasia. The final reports of these cases were almost the same. On FNAC, 13 cases were declared as malignant (6 cases) or suggestive of malignancy (3 cases) or suspicious for malignancy [4 cases (5.26%)]. Only 9 cases (11.84%) were clearly committed as malignant lesions, comprising of papillary carcinoma, anaplastic carcinoma and suggestive of follicular carcinoma. Comparison of malignant cases on histopathology (14 cases) was close to that of FNAC (13 cases). After comparison of FNAC results with histopathology, overall sensitivity of FNAC was found to be 90%, specificity 87.5%, and accuracy 87%, while positive predictive value (PPV) was 93% and negative predictive value (NPV) was 79.5%. In conclusion, we recommend this procedure in the light of views of other experts as a primary investigation of thyroid lesions. We strongly recommend the suggestion that in a patient with one or more thyroid nodule, FNAC should be advised for every patient for exclusion of cancer. We will also encourage the clinicians to embrace this procedure in the initial management of patients. As FNAC is inexpensive, sensitive, specific, and an accurate procedure it should be adapted as an initial investigation of thyroid diseases in all tertiary hospitals in developing countries like Pakistan.

[Value of intraoperative frozen-section analysis in thyroid surgery]

AIM OF STUDY

To assess the value of intraoperative frozen-section diagnosis in thyroid surgery and determine its limitations.

METHODS

This retrospective study examined the results of 1534 frozen sections of thyroid specimens analyzed over the 11-year period from 1995 through 2005 and their correlations with the final histological examination. Deferred responses were not taken into account for statistical calculations.

RESULTS

In our series, frozen-section diagnosis was concordant with subsequent histopathological examination in 92% of cases, discordant in 3%, and deferred in 5%. The global specificity of frozen section analysis for all histological subtypes was 99.8% and its sensitivity 67%. Its sensitivity for thyroid cancer was lower in follicular (42%) and papillary carcinoma (64%) than medullary (100%), anaplastic (100%), secondary (100%), mixed (100%), and insular carcinomas (86%).

CONCLUSION

In our series, as in the literature, most of the discordances between frozen-section and definitive diagnosis were associated with microfollicular lesions, which explain the low sensitivity of 67%. Our results demonstrate the reliability of intraoperative frozen-section analysis in thyroid surgery. Collaboration between pathologists, radiologists, and clinicians should be emphasized.