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Erschienen in:
01.08.2015 | Original Scientific Report
The Implementation of the Bethesda System for Reporting Thyroid Cytopathology Improves Malignancy Detection Despite Lower Rate of Thyroidectomy in Indeterminate Nodules
Erschienen in: World Journal of Surgery | Ausgabe 8/2015
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Background
The Bethesda system for reporting thyroid cytopathology (TBSRTC) was developed in 2009 to standardize the terminology for interpreting fine-needle aspiration (FNA) specimens.
Methods
A historical prospective case series design was employed. The study group included patients with a thyroid nodule classified as TBSRTC AUS/FLUS (B3) or FN/SFN (B4) in 2011–2012 in a tertiary university-affiliated medical center. Rates of surgery and malignancy detection were compared to our pre-TBSRTC (1999–2000) study.
Results
Of 3927 nodules aspirated, 575 (14.6 %) were categorized as B3/B4. Complete data were available for 322. Thyroidectomy was performed in 123 (38.2 %) cases: 66/250 (26.4 %) B3 and 57/72 (79.2 %) B4. Differentiated thyroid cancer was found in 66 (53.7 %) patients: 30/66 (45.5 %) B3 and 36/57 (63.2 %) B4 (p = 0.075). Operated patients were younger than the non-operated (B3: 52.4 ± 16 vs. 59.7 ± 13 years, p = 0.009; B4: 51.7 ± 15 vs. 60.5 ± 14 years, p = 0.042), and operated B3 nodules were larger than the non-operated (27.2 vs. 22.2 mm, p = 0.014). Additional FNA was done in 160 patients (49.7 %): 137/250 (54.8 %) B3 and 23/72 (31.9 %) B4 (p = 0.002). The additional B3 nodules aspirations yielded a diagnosis of B2 in 84 patients (61.3 %), B3 in 48 (35 %), and B4 in 5 (3.6 %). Of the 23 repeated B4 aspirations, B2 was reported in 5 (21.7 %), B3 in 12 (52.2 %), B4 in 4 (17.4 %), and B6 in 2 (8.7 %). The number of aspirated nodules was twice that reported in 1999–2000. The rate of indeterminate nodules increased from 6 to 14.6 %, the surgery rate decreased from 52.3 to 38.2 %, and the accuracy of malignancy diagnosis increased from 25.9 to 53.7 %.
Conclusions
The application of TBSRTC significantly improves diagnostic accuracy for indeterminate thyroid nodules, leading to higher rates of malignancy detection despite lower rates of thyroidectomies.