Declining role of frozen section in surgical planning for thyroid nodules

Needle biopsy (Bx) is superior to clinical selection of thyroid nodules for surgery. Is it superior to frozen section (FS) for surgical planning? Comparison of accuracy of the two procedures was made for 359 patients who underwent both procedures. Bx diagnoses consistent with a low risk of cancer predict a benign lesion at surgery with 90% accuracy. FS on the same patients was also 90% reliable in identifying benign or malignant nodules. Bx diagnoses consistent with a high risk of cancer predict a malignant lesion at surgery with 91% accuracy. FS on the same patients identified only 70% of the cancers. However, false positive diagnoses of cancer were less by FS. Bx diagnoses on nodules with an intermediate risk of cancer (32% to 43%) were insufficiently sensitive for reliable surgical planning. FS on the same nodules was also unreliable. Only three of 359 FS diagnoses contributed decisively to surgical planning. Reliance on Bx could eliminate as many as 99% of FSs.