ACR TI-RADS and ATA US scores are helpful for the management of thyroid nodules with indeterminate cytology

Abstract

BackgroundCytologically indeterminate thyroid nodules currently present a challenge for clinical decision-making. The main aim of our study was to determine whether the classifications, American College of Radiology (ACR) TI-RADS and 2015 American Thyroid Association (ATA) guidelines, in association with The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), could be used to stratify the malignancy risk of indeterminate thyroid nodules and guide their clinical management.MethodsThe institutional review board approved this retrospective study of a cohort of 140 thyroid nodules in 139 patients who were referred to ultrasound-guided fine-needle aspiration cytology (FNAC) from January 2012 to June 2016 with indeterminate cytological results (44 Bethesda III, 52 Bethesda IV and 44 Bethesda V) and in whom pre-FNAC thyroid US images and histological results after surgery were available. Each included nodule was classified by one radiologist blinded to the cytological and histological diagnoses according to the ACR TIRADS scores and the US patterns as recommended in the 2015 ATA guidelines. The risk of malignancy was estimated for Bethesda, TI-RADS scores, ATA US patterns and their combination.ResultsOf the 140 indeterminate thyroid nodules examined, 74 (52.9%) were histologically benign. A different rate of malignancy (p < 0.001) among Bethesda III, IV and V was observed. The rate of malignancy increased according to the US suspicion categories (p < 0.001) in both US classifications (TI-RADS and ATA). Thyroid nodules classified as Bethesda III and the lowest risk US categories (very low, low and intermediate suspicion by ATA and 2, 3 and 4a by TI-RADS) displayed a sensitivity of 95.3% for both classifications and a negative predictive value of 94.3 and 94.1%, respectively. The highest risk US categories (high suspicion by ATA and 4b,4c and 5 by TI-RADS) were significantly associated with cancer (odds ratios [ORs] 14.7 and 9.8, respectively).ConclusionsUltrasound classifications, ACR TI-RADS and ATA guidelines, may help guide the management of indeterminate thyroid nodules, suggesting a conservative approach to nodules with low-risk US suspicion and Bethesda III, while molecular testing and surgery should be considered for nodules with high-risk US suspicion and Bethesda IV or V.

The Diagnostic Role of Computed Tomography for ACR TI-RADS 4–5 Thyroid Nodules With Coarse Calcifications

“…In the present study, the malignancy rates is ∼11.7 and 45.2% for ACR-TIRADS 4 and 5 respectively, which were lower than some previous studies reported (the malignancy rates of 14.5-49.6% and 81.4-92.9% for ACR-TIRADS 4 and 5, respectively) (7,39,40). We considered this was related to the fact that the nodules we included were all coarse calcified nodules characterized as ACR-TIRADS 4 and 5 by ultrasound.…”

Risk Factors of Malignancy in Patients With Fine Needle Aspiration Biopsy Results Interpreted as “Suspicious for Follicular Neoplasm”

“…Amerykańskie Towarzystwo Radiologiczne zaproponowało system punktowy oparty na 5 cechach. Zmiany ogniskowe zostają zaklasyfikowane do odpowied niej kategorii na podstawie liczby punktów otrzymywanych za określone cechy: TR2 (2 pkt); TR3 (3 pkt); TR4 (4-6 pkt, TR4a − 4 pkt, TR4b − 5 pkt, TR 4c − 6 pkt) i TR5 (≥7 pkt) [41,42]. Oba modele ( według ATA oraz ACR) zostały porównane w pracach Middletona i wsp.…”

“…Autorzy konkludują, że zmiany ogniskowe zweryfikowane jako podejrzenie nowotworu pęcherzykowego z wysokim ryzykiem złośliwości na podstawie kryteriów ATA 2015 lub wynikiem 4b/4c/5 według ACR TI-RADS wiążą się z gorszym rokowaniem i stanowią wskazanie do leczenia operacyjnego. W przypadku mniejszego ryzyka złośliwości można rozważyć badania molekularne (jednak metody te są drogie i w Polsce nierefundowane) [41,42].…”

Systems of Risk Stratification of Malignancy by Ultrasound of Thyroid Nodules

“…In subjects with undetermined cytology (especially in the B-III and B-IV categories), a correlation between RSS with cytological category has been proposed, to further define on whom to perform follow-up, molecular tests, or surgery. In a retrospective study with 140 definitive pathology, US, and FNA results, a correlation between low-risk US categories (according to ATA and ACR-TIRADS) and low risk for malignancy in cases with a B-III cytology [23]. Barbosa et al reported that in cases with B-III cytology that also had a TIRADS category 2, 3, and/or 4, or a very low-risk/low risk/intermediate ATA category, the NPV to rule out malignancy was 94.1% and 94.3%, respectively, favoring a conservative approach in this scenario.…”

“…Nonetheless, in cases with B-III cytology and higher US risk categories (TI-RADS 4b, 4c, and 5; high-risk ATA), the NPV was 68 and 45,5%. The malignancy risk is higher in these cases, and it isn't possible to rule out malignancy with US alone [23].…”