Investigating the value of fine needle aspiration cytology in thyroid cancer

Background: Current guidance recommends the use of fine needle aspiration cytology (FNAC) as an essential investigation in patients presenting with a thyroid lump. Current literature suggests that the sensitivity of FNAC in thyroid nodules ranges between 80-90%. However, only very few studies have looked specifically at the sensitivity of FNAC in solely thyroid cancer patients. Aims: The aim of our study was to investigate the value of FNAC as a first-line investigation in patients with thyroid cancer. We aimed specifically to assess the sensitivity of FNAC within this group. Materials and Methods: Patients diagnosed with thyroid cancer between 2000-08 were identified from a local histopathology database. Sixty-seven case notes were retrieved, retrospectively reviewed and analyzed. Analysis included results of FNAC, ultrasound scanning and final histopathological diagnosis. Results: Analysis of the 56 patients who underwent FNAC revealed that a cytological grading of thy3 or greater was only given to 31 cases (55.3%). Conclusion: In this study, FNAC findings of thy3 or greater were reported only in 55.3% of proven thyroid cancer cases. This study highlights the greater diagnostic difficulties of thyroid cancer compared to other thyroid nodules. Our findings suggest that clinicians must interpret the results of this initial investigation with caution and consider the routine use of ultrasound scanning to help guide FNAC.