The role of intraoperative frozen sections for thyroid nodules

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.

Frozen section in thyroid gland follicular neoplasms: It's high time to abandon it!

Thyroid nodules are a very common clinical condition. The 2015 American Thyroid Association (ATA) guidelines recommend surgical excision for Bethesda IV nodules. The use of intraoperative frozen section (FS) has been recommended as a strategy to tailor the extent of the initial surgery. We critically evaluated the literature that discusses the utility and cost-effectiveness of FS to make an intraoperative decision in patients with thyroid nodules classified as follicular neoplasm. FS should not be recommended as a routine intraoperative test to assess for malignancy in thyroid follicular patterned lesions due to its low performance; the high number of deferred results; the inability to adequately assess histologically defining features; the improvements in risk stratification guiding total thyroidectomy; and the low cost-effectiveness of FS.

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.

A Retrospective Study to Assess the Role of Using Fine Needle Aspiration Cytology and Frozen Section in the Diagnosis of Thyroid Swelling

The most cost-effective test is fine needle aspiration cytology (FNAC). Many surgeons use intraoperative frozen section to confirm the FNAC findings and to guide the extent of thyroid surgery. Though it is a valuable tool in the diagnosis of the thyroid lesion and determining the extent of thyroid surgery, still in certain cases diagnosis can be incorrect or inconclusive, so histopathology of the excised specimen remains the most reliable test. The purpose of this study will be to compare the result attained by FNAC and frozen section of the thyroid to the final histopathological diagnosis, in order to establish their role in thyroid surgery today. A retrospective study with a total of 140 patients who underwent thyroid surgery at the ENT department, of a tertiary hospital in coastal Karnataka. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for FNAC and frozen section. The sensitivity, specificity, positive predictive rate, and negative predictive rate of frozen section was found to be 66.7%, 88.4%,76.6%, 82.4% respectively for detecting malignancy. This was found to be higher than the results of FNAC for the same which were 64.4%, 77.8%, 64.4%, 77.8% respectively. As the sensitivity of FNAC is similar to frozen section in detecting malignant cases, FNAC is a good tool for screening the patient for determining malignancy in thyroid, but frozen section is more specific in confirming the malignancy.