Is FNAC (fine needle aspiration cytology) a useful tool in detection of malignancy in thyroid surgery? A single...

To evaluate if FNAC (Fine Needle Aspiration Cytology) is a useful tool in the detection of malignancy in thyroid surgery. FNAC is used routinely as a preoperative diagnostic technique and surgical strategy is often adapted. But is FNAC such a good technique in defining surgical strategy?

We retrospectively reviewed all files of 703 patients operated from 1997 till today. We obtained the results of the FNAC, the final pathological diagnosis and these data were analyzed.

There were 161 male and 542 female patients. 72 out 703 patients had a malignancy. 241 patients (34.3%) had a preoperative FNAC-procedure. Male patients had significantly more malignancies (p = 0.006). In 183 patients (75.9%) the FNAC was benign, 28 patients (11.6%) showed malignancy, in 15 patients (6.2%) only blood was found and 15 patients (6.2%) showed an inconclusive result. 70.1% of the patients were true negative, 5.8% were true positive, 5.8% false positive, 5.8% false negatives, 5.8% of inconclusive results were malignant on pathology. This gives a sensitivity of 50% and specificity of 92.4%.

The specificity of FNAC in malignancy is high (92.4%) but a sensitivity of 50% is low. With these results adaptation of surgical strategy (hemithyroidectomy or total thyroidectomy) secondary to the results of the FNAC is not recommended. Free hand FNAC might be a reason for the relatively high percentage of inconclusive results. Ultrasound guided FNAC can improve the yield of the puncture. On top of that pathological interpretation of the cytology is not always straight forward.