Evaluation the Relationship Between Thyroid Nodule Size with Malignancy and Accuracy of Fine Needle Aspiration Biopsy (FNAB)

Abstract

Introduction: Some studies have shown largest thyroid nodule size, especially ≥4cm that can predict malignancy and reduce fine needle aspiration biopsy (FNAB) accuracy. Therefore, this study is designed to evaluate relationship between thyroid nodule sizes with malignancy and its effect on FNBA accuracy. Materials and Methods: a retrospective analytical study design aims to investigate all patients Positive and negative results of FNAB in all nodules were 3.5% and 6.3%, in <4cm nodules were 5.8% and 6.2% and in ≥4cm nodules were zero and 6.7%, respectively. The sensitivity, specificity, Positive predict value (PPV), negative predict value (NPV) and overall accuracy (OA) of FNAB in all nodules were 76.19%, 96.49%, 88.88%, 91.66% and 91.02%, and in <4cm nodules were 78.57%, 94.11%, 84.61%, 91.42% and 89.58%, and in ≥4cm nodules were 71.4%, 100%, 100%, 92% and 93.33%, respectively.Conclusion: the results of this study revealed that the size of the thyroid nodules is not reliable at predicting malignancy and should not be applied in medical decision making. FNAB showed good specificity but the sensitivity was low in our study. In ≥4cm nodules; FNAB sensitivity was decreased and accompanied by higher false-negative results. Furthermore, FNABs with suspicious results were associated with high probability of malignancy.

Thyroid cancer detection rate and associated risk factors in patients with thyroid nodules classified as Bethesda category III

“… 9 , 13 Conversely, Godazandeh et al . reported that in younger patients the prevalence of thyroid carcinoma is higher 16 , and in another study surgery without rFNA is recommended for younger patients. 14 Latter findings are in concordance with our results that younger age is a significant independent factor for malignancy in this Bethesda diagnostic category.…”

“…Nevertheless, this could be because of a selection bias based on younger patients being referred to surgery more often in our study, though this finding was not statistically significant. Nodule size is reported to have no predictive value of malignancy and it should not be used as a reliable factor for clinical decision making 16 , 17 , although Kamran et al . suggest a threshold of approximately 2 cm in nodule diameter with strong evidence that size > 2 cm is associated with an increased risk of well-differentiated thyroid cancer.…”

A Study to Evaluate the Size of Thyroid Nodules as an Indicator for Malignancy

“…Other study concludes that male gender, age ≥60 years old, microcalcification, cervical lymphadenopathy was risk factor of malignancy. [4,[8][9][10] Based on benign cytology features and low false negative rate of the FNAC patient required regular follow up with annual clinical examination and repeat ultrasound. Repeat cytology was recommend for patient with abnormal feature in ultrasound and changes in the size of the nodule.…”

Use of the TI-RADS scoring system in the evaluation of thyroid nodules

“…Thyroid nodules are very common in the general population and can be found clinically in 4-7% of the general population. However, it seems that the true prevalence of thyroid nodules is higher (the prevalence is from 8 to 65% in autopsy and from 19 to 35% in ultrasound survey) [1,2]. Although most thyroid nodules are benign hyperplastic lesions, past research has determined that thyroid cancer occurs in 5 to 15% of thyroid nodules [3][4][5].…”