Background: Fine-needle aspiration biopsy (FNAB) and frozen-section analysis of managing solitary thyroid nodules continue to generate considerable controversy.
Methods: This study was a retrospective review of 619 patients with solitary thyroid nodules who underwent thyroidectomy.
Results: Of 540 FNABs, 35 (6.5%) were positive for malignancy, 276 (51.1%) were benign, and 229 (42.4%) were suspicious. Only 5.1% were false negative, and 11.4% were false positive. Diagnostic FNAB sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for malignancy were 86.1%, 59.7%, 33.0%, 94.9%, and 64.6%, respectively. Of 569 patients analyzed by frozen section, diagnosis was deferred in 86 (15.1%) patients, and results were positive for malignancy in 92 (16.2%) and benign in 391 (68.7%). No false-positive results were noted, but 2.3% (391) were false negative. Of 86 deferred frozen sections, 11 (12.8%) patients had malignant tumors confirmed by permanent section. Diagnostic frozen-section sensitivity, specificity, PPV, NPV, and accuracy for carcinoma were 82.1%, 100%, 100%, 95.8%, and 96.5%, respectively. Sensitivity, specificity, PPV, NPV, and accuracy for frozen-section analysis for diagnosis of carcinoma in patients with suspicious FNAB were 83.9%, 100%, 100%, 94.9%, and 96.0%, respectively.
Conclusions: FNAB is a sensitive diagnostic modality in selecting patients who require surgery. Routine use of frozen-section analysis is unwarranted for benign FNAB results. Frozen section is specific and cost-effective in determining the extent of surgery in patients with suspicious or malignant FNABs.