The ongoing debate in thyroid surgery: should frozen section analysis be omitted?

Frozen Section in Diagnosis of Thyroid Swelling: Does It Still Have Role?

Purpose The present study correlates the frozen section diagnosis of thyroid swelling with the histopathological diagnosis and assesses the expression of immunohistochemical markers in malignant thyroid tumours. Also, the study aims to analyse the accuracy and limitations of the frozen section as an intraoperative tool for the diagnosis of thyroid swellings. Method Fifty-three cases of thyroid swelling were included in the study. Frozen section reports were classified as benign, malignant and deferred. A correlation between frozen section and histopathology examination (HPE) reports has been evaluated. The malignant cases confirmed on HPE were subjected to Immunohistochemistry (IHC) with TTF-1, Thyroglobulin, and CK-7. Results Among the 53 patients, 45 (84.9%) were females, and the majority were younger than 40 years (60.37%). On frozen section majority, 42 (79.25%) were benign, while a definitive diagnosis of malignancy was made in six cases (11.32%). On the frozen section, there were no false-positive cases, six true-positive cases, one false-negative case and 46 true-negative cases, with a sensitivity of 85.71%, specificity of 100%, the positive predictive value of 100%, the negative predictive value of 97.87% and diagnostic accuracy of 98.11% respectively. All the six papillary carcinomas and one follicular carcinoma showed immunoreactivity of tumor cells to TTF 1, CK 7 and Thyroglobulin. Conclusion There was a strong correlation between the frozen section and histopathological diagnosis. Still, it is not recommended in routine use for intraoperative diagnosis of thyroid swelling because of various limitations and the high diagnostic accuracy of FNAC. Adequate histopathologic diagnosis of thyroid disease is based on extensive subsampling of the specimen, which is not possible during an intraoperative frozen section procedure. If the frozen section is used, its limitations must be recognized, preferably based on first-hand data.

Medicolegal lessons learned from thyroidectomy-related lawsuits: an analysis of judicial precedents in South Korea from 1998 to 2019

Background

Thyroid cancer is one of the most common cancers in South Korea, and thyroidectomy is still frequently performed. As new diagnostic methods have led to a significant increase in the early detection of thyroid cancer worldwide, medical disputes related to thyroid surgery are also likely to increase. The purpose of this study was to investigate the causes of medical disputes related to thyroidectomy and to identify ways to prevent unnecessary disputes and malpractice.

Methods

We analyzed 35 judicial decisions involving thyroidectomy in South Korea from January 1998 to July 2019.

Results

The most common cause of lawsuits was "performance error during surgery" (n=19), especially "recurrent laryngeal nerve (RLN) injury" (n=7), of which five cases were ruled medical malpractice. For lawsuits involving misdiagnosis (n=14), five regarding fine needle aspiration cytology (FNAC) and frozen section examination were ruled malpractice. The most common malpractice related to informed consent was "lack of explanation about surgery complications" (n=10).

Conclusions

Surgeons should follow guidelines to protect themselves from diagnostic error dispute; performing FNAC more often might also prevent lawsuits. When the courts judge the surgeon's negligence in cases of RLN injuries, whether bilateral or unilateral, it is necessary to consider fully the surgeon's efforts to prevent RLN injuries. Providing information and building trust through sufficient patient-doctor communication is crucial.

Treatment of solitary thyroid nodules according to size, preoperative fine-needle aspiration cytology and frozen section: a retrospective single centre study

Background: In order to avoid unnecessary thyroidectomies, it is important to predict the nature of thyroid nodules the more accurately possible. The size of the nodule as a predictive factor for malignancy is very controversial. Another point of debate is the accuracy of preoperative fine-needle aspiration cytology (FNAC) and frozen section (FS). The aim of our study is to correlate the nodule size with the final histological diagnosis and to estimate the accuracy of preoperative FNAC and FS. Methods: Retrospective study including 387 operated patients with ultrasound-detected solitary thyroid nodules from 01 January 2001 to 31 December 2013. The following data were collected: patient age and sex, nodule size, FNAC, FS and final histology results. Results: The odds ratio for malignancy within nodules <40 mm was 2.12 (95% CI: 1.104-4.084). The specificity of FNAC was 97.78% and the negative predictive value (NPV) was 97.78% for nodules ≥40 mm and 93.2% and 96.5% for nodules <40 mm, respectively. The observed specificity and NPV of FS ranged from 98% to 100% and from 87.4% to 98%, respectively. When combining FNAC and FS, the specificity and the NPV were 99% and 98%, respectively. Conclusions: The nodule size is not a predictive factor for thyroid cancer and therefore nodules ≥40 mm should not be routinely resected. A lege artis preparation and performance of FNAC along with an expertise on cytological interpretation can considerably diminish false-negative rate. FS can offer additional accuracy on FNAC results and should, therefore, be a part of patient treatment.

Intraoperative measurement of thyroglobulin in lymph node aspirates for the detection of metastatic papillary thyroid carcinoma

Background

Among patients with papillary thyroid carcinoma (PTC), 30%–80% have cervical lymph node (LN) metastases, which are most commonly located in the central compartment. However, preoperative ultrasonography identifies malignant central compartment LNs in only 20%–30% of cases. We aimed to evaluate the diagnostic value of intraoperative thyroglobulin (Tg) measurement in fine-needle aspirates (FNA-Tg) of suspicious metastatic LNs.

Methods

In total, 75 patients (75 LNs) with PTC or suspected PTC were enrolled in this study. Suspicious metastatic LNs were isolated intraoperatively, and FNA-Tg was performed. Then, the Tg values were compared with the corresponding pathological results and preoperative ultrasonography.

Results

In total, 37 LNs were diagnosed as malignant, and 38 were benign. According to the receiver operating characteristic (ROC) curve, the optimal cutoff value of intraoperative FNA-Tg was 147.5 ng/mL (sensitivity, 81.1%; specificity, 100%; p=0.000). The sensitivity and specificity for detecting central compartment LN metastasis were 77.78% (21/27) and 100% (36/36), respectively. The corresponding sensitivity of preoperative ultrasonography was lower than that of FNA-Tg (p=0.000). Serum Tg-antibody (Ab), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) were not significantly associated with FNA-Tg values. There was no statistical correlation between preoperative serum Tg and intraoperative FNA-Tg (p=0.451).

Conclusion

Intraoperative FNA-Tg levels of suspicious metastatic cervical LNs can be useful for diagnosing metastatic PTC. Intraoperative LN-FNA-Tg may have an important role in determining which surgical procedure to perform.

Should subtotal thyroidectomy be abandoned in multinodular goiter patients from endemic regions requiring surgery?

The most convenient surgical procedure for benign thyroid diseases is still controversial. The aim of this study is to determine the recurrence rate and risk factors for recurrence after different thyroidectomy procedures in multinodular goiter patients. Patients were separated into two groups according to the detection of a recurrent nodule or not after thyroidectomy. Of the 748 patients, 216 (29%) had recurrence, while 532 had no recurrent nodule. The difference between surgical procedures described as subtotal (ST), near total (NT) and total thyroidectomy (TT) was statistically significant. Transient hypoparathyroidism was significantly higher in NT and TT, when compared to ST patients (P < 0.05). Young age, bilateral multinodular goiter and insufficient surgery are risk factors affecting recurrence for benign nodular thyroid disease. Currently, subtotal procedures should be discontinued and total or near total procedures should be preferred. Meanwhile, the probability of a higher risk of hypoparathyroidism should be kept in mind.

Treatment for papillary thyroid microcarcinoma

Aim of the study

The treatment for papillary thyroid microcarcinoma (PTMC), which is a tumor measuring less than 1 cm, is still a subject of controversy. The aim of this study is to retrospectively evaluate the patients diagnosed with PTMC in terms of their clinical and histopathological features.

Material and methods

A total of 153 consecutive patients with PTMC were treated, and their clinical and histopathological characteristics were reviewed. The tumor diameter was observed to range from 1.0 mm to 10 mm (mean of 5.8 mm). Histologically, 138 (90.2%) cases of classical papillary carcinoma and 15 (9.8%) cases of the follicular variant were noted. Multicentric tumors were found in 37 (24.2%) patients, of whom 12 (7.8%) had more than one PTMC on the same side and 25 (16.3%) displayed bilateral PTMC.

Results

The proportions of capsular invasion and lymph node metastasis were 11.8% (18/153) and 48.1% (39/81), respectively. One patient showed distant metastasis during follow-up and died fifteen months after the operation. PTMC showed a high incidence of multifocality and lymph node metastasis in the level VI central compartment. The optimal surgical strategy for PTMC was total thyroidectomy and central compartment node dissection.

Conclusions

Frozen tissue sections should be made for the prompt diagnosis of PTMC in all the thyroid nodules, except when the malignant diagnosis was already confirmed by cytology.

Thyroid nodule surgery: predictive diagnostic value of fine-needle aspiration cytology and frozen section

OBJECTIVES

The authors analyse the predictive diagnostic accuracy of fine-needle aspiration cytology (FNAC) and frozen section examination in adult patients operated for thyroid nodules.

PATIENTS AND METHODS

The same pathologist performed macroscopic and cytological examination, followed by frozen section examination on each operative specimen. FNAC results were classified into three groups: benign, malignant or suspicious of malignancy. Frozen section examination was also classified into three categories: benign, malignant or suspicious of malignancy when not all criteria of malignancy were present.

RESULTS

One hundred and sixty-six (82%) of the 202 patients included in the study were females. Patients had a mean age of 51 years. Thyroid carcinoma was diagnosed on final pathology in 22% of women and 25% of men. FNAC results were benign in 85% of cases, malignant in 9% of cases and atypical or suspicious in 6% of cases, with a specificity of more than 99% and a sensitivity, including and excluding microcarcinomas, of 36% and 48%, respectively. The diagnostic accuracy of FNAC was 84% and 89%, after excluding micro-carcinomas. Frozen section was benign in 85% of cases, malignant in 13% of cases and suspicious in 2% of cases, with a specificity of more than 99% and a sensitivity, including and excluding microcarcinomas, of 56% and 68%, respectively. The diagnostic accuracy of frozen section was 89% and 90%, after excluding microcarcinomas. The diagnostic accuracy of the combination of the two examinations was 94% after excluding microcarcinomas.

CONCLUSION

FNAC and frozen section have a comparable predictive diagnostic accuracy. Frozen section is requested by the surgeon not only on the basis of preoperative FNAC, especially when it is suspicious, or even indeterminate, but also in the light of the macroscopic surgical findings.

Utility of Intraoperative Frozen Sections during Thyroid Surgery

Objective. To describe the usefulness of intraoperative frozen section in the diagnosis and treatment of thyroid nodules where fine needle aspirate biopsies have evidence of follicular neoplasm. Study Design. Retrospective case series. Methods. All patients have a fine needle aspirate biopsy, an intraoperative frozen section, and final pathology performed on a thyroid nodule after initiation of the Bethesda System for Reporting Thyroid Cytopathology in 2009 at a single tertiary referral center. Sensitivity, specificity, positive predictive value, and negative predictive value are calculated in order to determine added benefit of frozen section to original fine needle aspirate data. Results. The sensitivity and specificity of the frozen section were 76.9% and 67.9%, respectively, while for the fine needle aspirate were 53.8% and 74.1%, respectively. The positive and negative predictive values for the fine needle aspirates were 25% and 90.9%, respectively, while for the frozen sections were 27.8% and 94.8%, respectively. There were no changes in the operative course as a consequence of the frozen sections. Conclusion. Our data does not support the clinical usefulness of intraoperative frozen section when the fine needle aspirate yields a Bethesda Criteria diagnosis of follicular neoplasm, suspicious for follicular neoplasm, or suspicious for malignancy at our institution.

Diagnostic accuracy of frozen section tests for surgical diseases

OBJECTIVE

To evaluate the accuracy of frozen section tests at different anatomical sites performed in an academic department of pathology.

METHODS

We conducted a retrospective study from a computerized database of all frozen section tests. These diagnoses were compared to definite paraffin, used as controls. The tests were divided into three groups: inconclusive, consistent and inconsistent, the latter being subdivided into false positives and false negatives. The main indications for examinations and anatomical sites involved with diagnostic disagreements were also analyzed.

RESULTS

Four hundred and thirty-three specimens were frozen tested, and the main indication was diagnostic (75.75%). In 404 tests (93.30%) diagnoses of biopsies in paraffin and frozen section were consistent. In 20 cases (4.62%) the results of frozen section biopsy were inconclusive and in 9 (2.08%) they were false negative. There were no false positive results. The most commonly assessed organ was the thyroid (25.64%). In the overall analysis, the body region most related with inconclusive diagnoses was the thyroid (seven cases) and in relation to specific sites it was the lungs/pleura/mediastinum (13.33%). Skin was the organ that showed more discordant diagnoses between frozen biopsies and paraffin.

CONCLUSION

The global accuracy of frozen section was 93.30%; for specific anatomical sites, diagnostic accuracy ranged from 86.67% to 100%.

Follicular nodules (THY3) of the thyroid: we recommend surgery

OBJECTIVE

To determine the need of total thyrodectomy for patients with follicular nodules of thyroid.

SUBJECTS AND METHODS

From January 2005 through June 2008, 2249 consecutive patients (438 males, 1811 females; mean age 54 yr, range 9-87) with thyroid nodules were submitted to 2518 ultrasound-guided fine-needle aspiration (USgFNA) for cytological examination. USgFNA were performed by experienced surgeon (RP) and endocrinologist (RGG) under ultra- sonographyc guidance, using a 10-MHz linear transducer. Liquid-based cytology was used.

RESULTS

All cytological samples were classified in 5 diagnostic classes (THY1, THY2, THY3, THY4, THY5) in agreement with the British Thyroid Association (BTA); 1.4% specimen were classified as THY5, 2.1% as THY4, 7.6% as THY3, 79.5% as THY2 and 9.4% as THY1. In 97% of THY5 patients, malignancy was found. Among THY4 patients, 95.5% were positive for thyroid tumor. Among THY3 patients, malignancy was found in 29.1%. THY3 patients with thyroid tumors were younger than those with benign lesions (46 ± 14.1 yr vs 50 ± 13.8 yr; p<0.05, t test). No statistical difference was found neither in malignancy frequency among men and women nor in mean size of nodules (24 ± 11.8 mm malignant vs 23 ± 9.4 mm benign).

CONCLUSIONS

this study provides evidence that USgFNA offers a very sensitive and accurate method in reducing THY1 samples and in detecting malignancy (>95% both in THY5 and THY4, and >29% in THY3 lesions). Our proposal is to submit to total thyroidectomy all patients with THY5 and THY4 lesions and THY3 thyroid nodule >1 cm.

[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.