Risk factors associated with malignancy and with triage to surgery in thyroid nodules classified as Bethesda category III (AUS/FLUS).
BACKGROUND
Selection of nodules for surgery diagnosed as Bethesda category III [atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category] is very important. We aimed at to define the predictive factors for malignancy and factors associated with triage to surgery.


METHODS
The records of all patients with nodules who underwent fine needle aspiration biopsy (FNAB) and classified by Bethesda reporting system as AUS/FLUS between 2011 and 2015 at our institution were reviewed. Univariate and multivariate analysis were performed to select independent factors associated with thyroid cancer and with triage to surgery. Using independent risk factors for malignancy predictive index categories were created.


RESULTS
Of the 485 patients who were classified as AUS/FLUS on initial FNAB, 153 underwent surgery with the associated malignancy rate of 22.8%. The malignancy rates for AUS/FLUS patients with and without repeat FNAB were 37.5% and 16.2%, respectively. Multivariate logistic regression analysis revealed that solid structure, microcalcification, hypoechogenicity, increased vascularization, and irregular margin were found to be significant and independent risk factors associated for malignancy, and solid structure, microcalcifications, increased nodule size (≥2 cm) and younger patient age (<65 years) were associated with triage to surgery.


CONCLUSIONS
Our findings showed that using predictive factors for malignancy in AUS/FLUS category as risk indices, an important proportion of patients (35%) who had nodules without any risk factors could be spared unnecessary surgery. We suggest that predictive indices should be considered for selection of the patients to triage to surgery.
['Kuru|B|B|', 'Atmaca|A|A|', 'Tarim|I A|IA|', 'Kefeli|M|M|', 'Topgul|K|K|', 'Yoruker|S|S|', 'Elmali|M|M|', 'Danaci|M|M|']
D018263:Adenocarcinoma, Follicular D000328:Adult D000368:Aged D044963:Biopsy, Fine-Needle D002471:Cell Transformation, Neoplastic D015331:Cohort Studies D016001:Confidence Intervals D005260:Female D005500:Follow-Up Studies D006801:Humans D008297:Male D008875:Middle Aged D009361:Neoplasm Invasiveness D009367:Neoplasm Staging D016017:Odds Ratio D011237:Predictive Value of Tests D012189:Retrospective Studies D018570:Risk Assessment D013964:Thyroid Neoplasms D016606:Thyroid Nodule D013965:Thyroidectomy D016896:Treatment Outcome D014218:Triage D057832:Watchful Waiting
Atypia of undetermined significance Bethesda III category Factors to triage to thyroid surgery Predictive factors for thyroid malignancy Selection of nodules for thyroid surgery