Limitation of intraoperative frozen section during thyroid surgery

Combined fine-needle aspiration and selective intraoperative frozen section to optimize prediction of malignant thyroid nodules: A retrospective cohort study of more than 3000 patients

BACKGROUND

Preoperative fine-needle aspiration (FNA) is widely used to differentiate malignant from benign thyroid nodules, while intraoperative frozen sections (FS) are suggested as a systematic supplement for intraoperative decision-making, but limitations still remain for both procedures.

METHODS

Medical records of 3807 patients with thyroid nodules who underwent both pathological diagnoses (FS and FNA) at our hospital were reviewed. The diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FNA and FS were also evaluated. We further designed an optimal integration scheme (FNA+selective FS) to predict thyroid nodule malignancy. Finally, the efficiency of the proposed integrated diagnostic model was validated using an independent external cohort.

RESULTS

For distinguishing malignant nodules, FNA had an accuracy of 90.3%, sensitivity of 90.7%, specificity of 85.2%, PPV of 98.8% and NPV of 40.4%. In contrast, the FS represented higher discriminative power (Accuracy, 94.5%; Sensitivity, 94.1%; Specificity, 100%; PPV, 100%; and NPV, 55.6%). we proposed the selective usage of FS (removed nodules with Bethesda category VI from routine FS, ~1/3 of total). The integrated new diagnostic model of FNA plus selective FS (FNA+sFS) achieved accuracy of 96.9%, sensitivity of 97.3%, specificity of 92%, PPV of 99.4%, and NPV of 71.6% (NRI=0.135, 95% CI 0.103-0.167, P <0.001) and was successfully applied to an external cohort (N=554).

CONCLUSION

Compared with the FNA diagnostic system, FS has an increased ability to distinguish benign and malignant thyroid nodules. The newly proposed integrated diagnostic model of FNA + selective FS can optimize the accuracy of diagnosis.

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.

Management of Thyroid Nodules in Deceased Donors With Comparison Between Fine Needle Aspiration and Intraoperative Frozen Section in the Setting of Transplantation

Introduction:

Newly discovered thyroid nodules in deceased donors are investigated to rule out cancer that can be transmitted, but there are no established protocols. The aim of the study was to compare fine needle aspiration versus intraoperative frozen section in the donor management with limited time.

Methods:

Data were extracted only from the records of Italian second opinion consultation service in the years 2016 to 2017 and included donor details, pathology diagnoses, complications, transmission risk profile, and impact on transplantation.

Results:

Among 31 deceased donors with thyroid nodules, we documented 4 with a clinical history of cancer and 27 with a newly discovered nodule. The latter was evaluated by thyroidectomy with frozen section in 22 and fine needle aspiration in 5. Among all donors, 7 had papillary thyroid carcinoma with negligible transmission risk, whereas 8 with unacceptable risk. Two donors presented major bleeding after thyroidectomy, with organ discard in 1 case. Transplantation was delayed in 4 cases that were evaluated with frozen section.

Discussion:

There was no uniform approach for the investigation of thyroid nodules. Our results showed that fine needle aspiration was more accurate and useful than frozen section. Fine needle aspiration had minor economic impact and a far less rate of bleeding/hemodynamic complications, potentially delaying and compromising organ recovery. Our results suggested considering fine needle aspiration as a first step in the evaluation of thyroid nodules in donors.