Purpose: This study aims to determine the utility of the Bethesda category and its association with BRAF mutation in prediction of the papillary thyroid cancer (PTC) stage.
Methods: A prospective study analyzed patients who had ultrasound-suspicious thyroid nodules, underwent FNA and cytological examination, and were classified according to the Bethesda system. Patients from Undetermined Significance Or Follicular Lesion Of Undetermined Significance (AUS/FLUS), Follicular Neoplasm or Suspicious for a Follicular Neoplasm (FN/SFN), Suspicious for Malignant Cells (SMC), and Positive for Malignant Cells (PMC) groups were examined for the BRAF mutation and had a thyroid surgery. Demographical and histological features and stage of the disease were evaluated for PTC patients in accordance with the Bethesda category and its association with BRAF mutation.
Results: Three hundred eight of all patients underwent operation. One hundred forty-three (46.4%) of them were diagnosed with PTC. In 14 (9.8%) PTC cases, FNA biopsies were classified as AUS/FLUS, 23 (16.1%) as FN/SFN, 41 (28.7%) as SMC, and 65 (45.5%) as PMC. I-II stages of PTC were diagnosed for 88 (61.5%) patients and III-IVA for 55 (38.5%). Patients from the SMC and PMC groups had larger tumors, higher incidence of lymph node metastases, classical PTC type, B-type Raf (BRAF) positive, and III-IVA stage cancer, than patients from the AUS/FLUS and FN/SFN groups. When comparing 27 (18.9%) BRAF-negative patients from the AUS/FLUS and FN/SFN groups with 116 (81.1%) BRAF-negative patients from the SMC and PMC groups and all BRAF-positive patients, the prediction of more aggressive histological features and stage was slightly improved.
Conclusions: Higher Bethesda categories are associated with higher stages of PTC. Association of the Bethesda category with BRAF mutation can slightly improve the value of stage prediction.
Keywords: BRAF mutation; Bethesda system; Fine-needle aspiration; Papillary thyroid cancer; Thyroid.