Early diagnosis by FNA cytology should not influence the outcome of differentiated thyroid cancer.

ABSTRACT

In oncology, the early cancer detection is recognized as associated with good patient's prognosis. Then, one could expect that differentiated thyroid carcinoma (DTC) undergone fine-needle aspiration cytology (FNA) early have better outcome. Aim of this study was to investigate if DTC prognosis is improved by early FNA diagnosis. DTCs followed-up at our institution were included. Information about initial management of thyroid lesion, FNA, surgery, and postoperative follow-up was collected. Cytologies were classified according to British Thyroid Association (BTA). The final series comprised 219 DTCs, of which 22 (10%) recurred. The length of time between nodule appearance and cancer treatment was significantly (p<0.0001) shorter in patients who had undergone FNA than those who had not. In the FNA group, 73 patients underwent biopsy within six months, 25 at 7-12 months, and 43 after at least one year. Regardless of this highly significant (p<0.0001) difference, the results of TNM staging and cancer recurrence rate were no different between these three subgroups. This result was confirmed in DTCs larger than 1 cm submitted to FNA within 12 months or later. When we evaluated the impact of nodule's presentation on DTC outcome, clinically discovered cancers were significantly associated with relapse (OR 2.81) and advanced TNM stages (p=0.03). These data show a lack of clinical impact of the delayed diagnosis of DTC. Also, the postoperative outcome of these patients should not be influenced by the timing of FNA. Instead, DTC patients with preoperative clinical nodule appearance should be considered at higher risk of relapse.