Role of frozen section analysis in nodular thyroid pathology

Abstract Introduction Frozen section (FS) analysis used to be the principal examination guiding surgical strategy. The development and recent standardization of fine-needle aspiration cytology (FNAC) challenges it as a systematic attitude. The present study assessed the current contribution of FS, comparing it with FNAC as a diagnostic tool guiding surgery. Material and methods A retrospective diagnostic study analyzed 1515 thyroid samples over a 6-year period. Two hundred and fifty-two of the patients had undergone both FNAC (analyzed in our unit) and FS, revealing 69 cancers. Results The sensitivity and specificity of FS and FNAC were 75.36% and 100% versus 31.88% and 100%, respectively. In case of malignancy on FNAC (22 patients), FS did not influence indications for surgery. In case of non-malignant FNAC findings, FS diagnosed cancer in 13% of cases (30/230). In the subgroup of follicular lesions (Bethesda 3 and 4), FS modified surgical strategy in only 6.2% of cases (6/97), but diagnosed 13 of the 16 cancers (81.25%) in case of Bethesda 5 on FNAC (21 cases) and in 9 of the 13 cancers (69%) associated with non-diagnostic FNAC results (Bethesda 1: 70 cases). Conclusion Although its contribution is small, FS optimizes surgery in certain cases. Systematic implementation may be economically justified, especially in follicular lesions diagnosed on FNAC, improving interpretation of a difficult and operator-dependent test, as is essential in certain FNAC results.