Thyroid Frozen Sections in Patients With Preoperative FNAs: Review of Surgeons' Preoperative Rationale, Intraoperative Decisions, and Final Outcome

The Role of Frozen Section Examination in Thyroid Surgery

In endocrine pathology, frozen section (FS) examination is most commonly used for the intraoperative evaluation of thyroid and parathyroid tumors, as well as cervical lymph nodes. In the past, frozen section was considered a fundamental tool in thyroid surgery. However, with advancements in preoperative ultrasound and fine-needle aspiration biopsy (FNAB), there have been increasing queries about its routine use due to the improved preoperative diagnosis. Nowadays, while the use of FS during thyroidectomy has decreased, it is still used as an additional method for different purposes intraoperatively. FS may not always provide definitive results. If FS will alter the surgical plan or extent, it should be applied. Routine FS is not recommended for evaluating thyroid nodules. But in addition to FNAB, if FS results may change the operation plan or extent, they can be utilized. FS should not be applied for thyroid lesions smaller than 1 cm, and the entire lesion should not be frozen for FS. For the assessment of thyroid nodules, the use of FS is recommended based on the Bethesda categories of FNAB. In Bethesda I category nodules, FS may contribute to distinguishing between malignant and benign lesions and guide surgical treatment. In Bethesda II nodules, where the malignancy rate is low, the performance of FNAB and FS can be compared, but it's not recommended due to the lack of a significant contribution to the surgical strategy. The sensitivity of FS in Bethesda III and IV nodules is low; its contribution to the diagnosis is limited, and it does not provide an apparent benefit to treatment; therefore, it is not recommended. In Bethesda V nodules, FS can effectively confirm the malignancy diagnosis, contribute to the surgical strategy, and reduce the possibility of completion thyroidectomy, and accordingly, it is recommended for use. Nonetheless, in Bethesda V nodules with a benign FS report, the malignancy rate remains high, so it should not be used to rule out malignancy. In Bethesda VI nodules, the performance of FS is lower or comparable to FNAB and does not significantly contribute to the treatment strategy; hence, it is not recommended. Particularly in patients with papillary thyroid cancer, intraoperative FS can be effective in detecting extrathyroidal extension and can assist the surgeon in determining the extent of thyroid surgery and central neck dissection. FS has high sensitivity and specificity in evaluating the lymphatic status of the central region intraoperatively and can be used to determine the extent of central compartment node dissection. During thyroidectomy, FS examination can be used in recognizing parathyroid tissue and distinguishing it from fatty tissue, thymus, thyroid, lymph nodes, especially in differentiating metastatic lymph nodes.

The incidence and features of Delphian lymph node involvement in patients with papillary thyroid carcinoma

Introduction

In papillary thyroid cancer patients, the extent of dissection is still a matter of debate. Evaluating Delphian lymph nodes (DLNs) during the surgery has been speculated as a valuable tool to determine the extent of dissection. Herein, we aimed to evaluate the incidence and features of DLNs involvement in patients with papillary thyroid carcinoma.

Method

We conducted this cross-sectional study among surgical cases of papillary thyroid cancer. Patients were divided based on their DLNs involvement status. Their age, gender, location of the mass, lymphatic involvement, tumor size, tumor characteristics, pathology report, and operation note features were compared between the two groups. Definitive pathology slides of the patients were evaluated regarding DLN features.

Results

Of the 61 patients (mean age: 38.2 ± 12.0), 45 (73.8%) were females. In 13 (21.3%) patients, DLNs involvement was reported. A statistically significant relationship was noted between DLNs involvement and other lymph nodes' involvement on the same side of the mass (P < 0.001), the opposite side (P = 0.041), and also central lymph nodes (P < 0.001). Vascular invasion was also significantly higher among patients with DLNs involvement (P = 0.012).

Conclusion

Since DLNs involvement is significantly associated with extensive nodal involvement, intraoperative evaluation of DLNs is recommended to establish the extent to which dissection should be performed.

Identification of a 3-Gene Prognostic Index for Papillary Thyroid Carcinoma

The accurate determination of the risk of cancer recurrence is a critical unmet need in managing thyroid cancer (TC). Although numerous studies have successfully demonstrated the use of high throughput molecular diagnostics in TC prediction, it has not been successfully applied in routine clinical use, particularly in Chinese patients. In our study, we objective to screen for characteristic genes specific to PTC and establish an accurate model for diagnosis and prognostic evaluation of PTC. We screen the differentially expressed genes by Python 3.6 in The Cancer Genome Atlas (TCGA) database. We discovered a three-gene signature Gap junction protein beta 4 (GJB4), Ripply transcriptional repressor 3 (RIPPLY3), and Adrenoceptor alpha 1B (ADRA1B) that had a statistically significant difference. Then we used Gene Expression Omnibus (GEO) database to establish a diagnostic and prognostic model to verify the three-gene signature. For experimental validation, immunohistochemistry in tissue microarrays showed that thyroid samples’ proteins expressed by this three-gene are differentially expressed. Our protocol discovered a robust three-gene signature that can distinguish prognosis, which will have daily clinical application.

Targeted use of intraoperative frozen-section analysis lowers the frequency of completion thyroidectomy

BACKGROUND

The impact of intraoperative frozen section (iFS) analysis on the frequency of completion thyroidectomy for the management of thyroid carcinoma is controversial. Although specialized endocrine centres have published their respective results, there are insufficient data from primary and secondary healthcare levels. The aim of this study was to analyse the utility of iFS analysis.

METHODS

In the Prospective Evaluation Study Thyroid Surgery (PETS) 2 study, 22 011 operations for benign and malignant thyroid disease were registered prospectively in 68 European hospitals from 1 July 2010 to 31 December 2012. Group 1 consisted of 569 patients from University Medical Centre (UMC) Mainz, and group 2 comprised 21 442 patients from other PETS 2 participating hospitals. UMC Mainz exercised targeted but liberal use of iFS analysis for suspected malignant nodules. iFS analysis was compared with standard histological examination regarding the correct distinction between benign and malignant disease. The percentage of completion thyroidectomies was assessed for the participating hospitals.

RESULTS

iFS analysis was performed in 35.70 per cent of patients in group 1 versus 21.80 per cent of those in group 2 (risk ratio (RR) 1.6, 95 per cent c.i. 1.5 to 1.8; P < 0.001). Sensitivity of iFS analysis was 75.0 per cent in group 1 versus 63.50 per cent in group 2 (RR 1.2, 1.2 to 1.3; P = 0.040). Completion surgery was necessary in 8.10 per cent of patients in group 1 versus 20.8 per cent of those in group 2 (RR 0.4, 0.2 to 0.7; P = 0.001).

CONCLUSION

iFS analysis is a useful tool in determining the appropriate surgical management of thyroid disease. Targeted use of iFS was associated with a significantly higher sensitivity for the detection of malignancy, and with a significantly reduced necessity for completion surgery.

Thyroid surgery in children and young adults: potential overtreatment and complications

Purpose

Thyroid nodules in the pediatric population are more frequently associated with malignant thyroid disease than in adult cohorts. Yet, there is a potential risk of surgical overtreatment. With this single center study, an analysis of potential overtreatment for suspected malignant thyroid disease in children and young adults was aimed for.

Methods

In a period from 2005 to 2018, 155 thyroid operations in children and young adults performed at the University Medical Center Mainz, Germany, were analyzed (patient age 3–20 years, 117 female). Cases were categorized for preoperative diagnosis: non-malignant (group I, n = 45) and malignant thyroid disease (group II, n = 110). Postoperative parameters (histology, complication rates) were assessed and compared between groups.

Results

91.1% of group I were histologically benign. 44.5% of group II harbored malignancy. Permanent hypoparathyroidism was documented in group I (2.7%) and in group II (1.4%, p = 1.000). Wound infections were absent in group I but observed in group II (0.9%, p = 1.000). Transient vocal cord palsy was recorded only in group I (2.3%, 2/85 vs. 0/177 nerves at risk, p = 0.104). Permanent vocal cord palsies were absent.

Conclusion

Preoperative diagnoses were correct in over 90% of group I and in nearly 45% of group II. The high proportion of carcinomas in group II ruled out the issue of potential overtreatment. The risk of severe postoperative complications was equally low in both patient groups.

Electronic supplementary material

The online version of this article (10.1007/s00423-020-01896-x) contains supplementary material, which is available to authorized users.

Malignancy Rate in Thyroid Nodules with Atypia or Follicular Lesion of Undetermined Significance

Introduction  Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) is one of the six diagnostic categories of the Bethesda System for Reporting Thyroid Cytopathology. The prevalence of malignancy among Bethesda category III cytology is variable, ranging from 5% to 37% in the literature. Objective  To determine the rate of malignancy in thyroid nodules reported as Bethesda category III. Methods  A total of 495 patients underwent surgical intervention for thyroid nodules from January 2015 to December 2017. The present study included 81 cases reported as Bethesda category III, and their medical records were reviewed. Results  Out of 495 fine-needle aspiration cytology samples, 81 (16.4%) samples were labeled as AUS/FLUS. Among these 81 patients, the mean age was 43.0 years (± 13.9), with only 11 (14%) patients older than 55 years of age. Most of our patients were female ( n  = 69; 85.2%), and the rest were male. The rate of malignancy based on the final histology was of 33.3% ( n  = 27). The majority were 17 cases (21%) of papillary carcinoma, followed by follicular carcinoma ( n  = 6) (7.4%). Conclusion  The risk of malignancy can be higher than it is commonly believed, and guidelines should be based on the data from the institutions themselves for a better assessment of the outcomes.

Role of frozen section in the surgical management of indeterminate thyroid nodules

Indeterminate thyroid nodules (ITNs) correspond to the categories III (atypia of undetermined significance or follicular lesion of undetermined significance) and IV (follicular neoplasm or suspicious for a follicular neoplasm) of the Bethesda system for reporting thyroid cytopathology. Their malignancy risk is 5-15% and 15-30% respectively, imposing surgical treatment for definitive diagnosis. Thus, they represent a diagnostic and therapeutic challenge given the risk of over or under treatment. Several teams continue to perform systematic intraoperative frozen sections (FS) in order to guide the initial extent of surgery and to avoid a two-stage thyroidectomy. FS have a very high specificity and positive predictive value for the diagnosis of malignancy allowing a one-stage total thyroidectomy if the result is positive. However, this attitude is highly controversial; and this review of the literature demonstrates that FS is of little contribution in this setting, due to low sensitivity and high false-negative rates. In fact, for these lesions, a careful and comprehensive evaluation of the tumor capsule is mandatory in order to visualize a capsular or a vascular invasion permitting to make the diagnosis of malignancy. However, this assessment is only possible on permanent section. Moreover, FS can jeopardize the detection of signs of capsular invasion on final pathologic examination. The recent development of molecular testing results in a better preoperative diagnosis, thus reducing even more the need for intraoperative FS. Contrasting with their limited role in Bethesda III and IV categories, FS are useful in guiding the preoperative management of Bethesda V category nodules, given their high negative and positive predictive values. Intraoperative FS of ITNs are of little use and are not recommended systematically. Their use should be restricted to elderly, high anesthetic risk, or poorly compliant patients for whom an eventual subsequent complementary surgery may be problematic.

Is Frozen-Section Analysis During Thyroid Operation Useful in the Era of Molecular Testing?

BACKGROUND

With the increased use of molecular testing of thyroid fine-needle biopsies, the frequency and extent of thyroid resection for thyroid nodules has changed. Although the role of frozen-section analysis of the thyroid has been reduced markedly in recent years, many surgeons still routinely use it intraoperatively. We sought to determine the utility of frozen section during thyroidectomy in the era of molecular testing.

STUDY DESIGN

We reviewed 236 consecutive patients who had thyroidectomy with intraoperative frozen-section analysis at our institution between November 2015 and October 2017. We re-reviewed the preoperative diagnosis, frozen-section diagnosis, final pathology, and whether operative management changed from the initial plan based on frozen section.

RESULTS

Mean age of the patients was 55.6 ± 14.1 years, and 83% were female. Of the 236 patients, frozen section did not change the intraoperative management in 225 (95%). Of the 11 patients whose thyroid operation was modified, the operation was either too much or not enough in 6 patients. In only 5 (2.1%) patients, frozen-section analysis correctly changed the extent of thyroidectomy.

CONCLUSIONS

Thyroid frozen-section analysis adds cost and time to thyroid operations without notable benefit. In our cohort, only 2.1% of frozen sections accurately changed intraoperative management. We recommend against its routine use.

Utility of Intraoperative Frozen Section in Large Thyroid Nodules

OBJECTIVE

To determine if the routine use of intraoperative frozen section (iFS) results in cost savings among patients with nodules >4 cm with nonmalignant cytology undergoing a thyroid lobectomy.

STUDY DESIGN

Case series with chart review; cost minimization analysis.

SETTING

Single academic center.

SUBJECTS AND METHODS

Records were reviewed on a consecutive sample of 48 patients with thyroid nodules >4 cm and nonmalignant cytology who were undergoing thyroid lobectomy in which iFS was performed between 2010 and 2015. A decision tree model of thyroid lobectomy with iFS was created. Comparative parameters were obtained from the literature. A cost minimization analysis was performed comparing lobectomy with and without iFS and the need for completion thyroidectomy with costs estimated according to 2014 data from Medicare, the Bureau of Labor Statistics, and the Nationwide Inpatient Sample.

RESULTS

The overall malignancy rate was 25%, and 33% of these malignancies were identified intraoperatively. When the malignancy rates obtained from our cohort were applied, performing routine iFS was the less costly scenario, resulting in a savings of $486 per case. When the rate of malignancy identified on iFS was adjusted, obtaining iFS remained the less costly scenario as long as the rate of malignancies identified on iFS exceeded 12%. If patients with follicular lesions on cytology were excluded, 50% of malignancies were identified intraoperatively, resulting in a savings of $768 per case.

CONCLUSIONS

For patients with nodules >4 cm who are undergoing a diagnostic lobectomy, the routine use of iFS may result in decreased health care utilization. Additional cost savings could be obtained if iFS is avoided among patients with follicular lesions.

Economic Impact of Frozen Section for Thyroid Nodules with "Suspicious for Malignancy" Cytology

Objective To perform a cost analysis of the routine use of intraoperative frozen section (iFS) among patients undergoing a thyroid lobectomy with "suspicious for malignancy" (SUSP) cytology in the context of the 2015 American Thyroid Association guidelines. Study Design Case series with chart review; cost minimization analysis. Setting Academic. Subjects and Methods Records were reviewed for patients with SUSP cytology who underwent thyroid surgery between 2010 and 2015 in which iFS was utilized. The diagnostic test performance of iFS and the frequency of indicated completion/total thyroidectomies based on the 2015 guidelines were calculated. A cost minimization analysis was performed comparing lobectomy, with and without iFS, and the need for completion thyroidectomy according to costs estimated from 2014 data from Medicare, the Bureau of Labor Statistics, and the Nationwide Inpatient Sample. Results Sixty-five patients met inclusion criteria. The malignancy rate was 61.5%, 45% of which was identified intraoperatively. The specificity and positive predictive value were 100%. The negative predictive value and sensitivity were 83% and 95%, respectively. Completion/total thyroidectomy was indicated for 9% of patients; 83% of these individuals had findings on iFS that would have changed management intraoperatively. Application of the new guidelines would have resulted in a significant reduction in the frequency of conversion to a total thyroidectomy when compared with the actual management (26.1% vs 7.7%, P = .005). Performing routine iFS was the less costly scenario, resulting in a savings of $474 per case. Conclusion For patients with SUSP cytology undergoing lobectomy, routine use of iFS would result in decreased health care utilization.

The futility of intraoperative frozen section in the evaluation of follicular thyroid lesions

OBJECTIVE

Investigate the utility of intraoperative frozen section (iFS) in patients with follicular thyroid lesions following publication of the 2015 American Thyroid Association (ATA) guidelines.

STUDY DESIGN

Retrospective chart review.

METHODS

Patient demographics, preoperative cytology, frozen pathology, and final pathology were reviewed on patients undergoing thyroid surgery at a tertiary care hospital in which iFS was utilized over a 5-year period. The test performance of iFS and the frequency of indicated completion/total thyroidectomies pre- and postpublication of the 2015 ATA guidelines were calculated.

RESULTS

One hundred and one patients met inclusion criteria: 54 patients with follicular lesions of undetermined significance (FLUS) and 47 patients with a cytologic diagnosis of suspicious for follicular neoplasm/follicular neoplasm. The malignancy rate was 36%, but only 14% of malignancies were identified on iFS. A definitive benign or malignant diagnosis was given on iFS in only 21% of cases, and operative management was altered in two cases as a result of iFS. There was a statistically significant reduction in the frequency of indicated total/completion thyroidectomies based on high-risk features as a result of the 2015 ATA guidelines compared to prior recommendations (20.8% vs. 5.0%, P = < 0.001). None of these patients had findings on iFS that would have altered management intraoperatively.

CONCLUSION

Intraoperative frozen section offers minimal diagnostic utility in the evaluation of follicular thyroid lesions. Updates in the 2015 ATA guidelines further diminish its potential to impact management intraoperatively. Significant improvements in its ability to identify malignancies would be needed to justify its use.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1501-1505, 2018.