Endocrine Abstracts

Introduction: Fine needle aspiration cytology(FNAC) is the mainstay for evaluation of nodular thyroid disease. Internationally reported prevalence for Bethesda I(unsatisfactory sample) category is 5-60%. Several factors may determine this result, including patient and nodules’ features as well as both FNAC performer and pathologists’ skills. Few studies have evaluated pre-procedure factors associated with unsatisfactory cytology results. If present, recognizing these factors, before performing FNAC, could help to adapt technique performance and sampling.

Objectives: Our aim was to determine clinical predictors of FNAC Bethesda I category.

Materials and Methods: Retrospective study of nodules submitted to FNAC, between January 2016 and December 2021. Clinical data from patients with FNAC Bethesda I category was retrieved and compared to Bethesda II to VI categories regarding gender, age, history of cervical radiation and malignancy, family history of thyroid disease, multinodular goitre, nodule’s side, location and largest diameter, EU-TIRADS ultrasound classification, TSH and anti-thyroid peroxidase and anti-thyroglobulin antibodies. A multivariate logistic regression was used to evaluate putative predictors of unsatisfactory results, including variables with different distribution between groups.

Results e conclusions: Included 1617 nodules in 1525 patients, 625(38.6%) with Bethesda I results after FNAC. Among these, in 140(22.4%) nodules, patients were male, their median age was 60(50-69) years old, previous cervical radiation and family history of benign thyroid disease’s prevalence was 27(4.3%) and 217(34.7%), respectively; most nodules[296(47.4%)] were located on the right lobe and in the middle third of the lobe[299(47.8%)]. Median TSH was 1.30(0.80-2.06)mUI/l. Nodules were classified, on ultrasound, as EU-TIRADS 2, 3, 4 and 5 in 62(9.9%),211(33.8%),265(42.4%) and 87(13.9%), respectively. The median largest diameter was 21.0(16.00-29.25)mm. Male gender, older age, nodule location and EU-TIRADS were significantly associated with unsatisfactory results in the univariate analysis. Variables included in the multivariate logistic regression were male gender, age, EU-TIRADS and nodule location. Male gender(OR 1.53 CI 95% 1.17-1.99, P = 0.002), age(OR 1.01 CI 95% 1.00-1.02, P = 0.008, per year), EU-TIRADS 3 to 5(OR 1.66 CI 95% 1.19-2.34, P = 0.003, OR 2.69 CI 95% 1.92-3.78, P < 0.001 and OR 2.37 CI 95% 1.56-3.59, P < 0.001, respectively), in comparison with 2, and location in the lower and upper thirds of the lobe(OR 1.409 CI 95%1.098-1.809, P = 0.007 and OR 1.718 CI 95% 1.131-2.610, P = 0.011, respectively), in comparison with the middle third, were independently associated with unsatisfactory results. In this highly Bethesda I prevalent cohort, older age, male gender, EU-TIRADS 3 to 5 nodules located at upper/lower thyroid poles were associated with higher risk of unsatisfactory FNAC.