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Thyroid nodule ultrasound accuracy in predicting thyroid malignancy based on TIRADS system.

BACKGROUND
A frequent prevalence of thyroid nodules in patients prioritizes the need for an accurate method that characterizes them as benign or malignant. Fine-needle aspiration biopsy (FNAB) and thyroid ultrasonography (USG) are currently used for this purpose. However, since FNAB is complicated, time-consuming and expensive, thyroid USG, a fast and highly sensitive method, is preferably used. Although USG is reported as a suitable method for characterization of thyroid nodules, there are some contrasting studies available which report its limited use in the differentiation of benign and malignant thyroid nodules.


OBJECTIVES
This meta-analysis aims to assess the accuracy of ultrasound in predicting thyroid cancer in terms of sensitivity, specificity and diagnostic odds ratios (ORs) for positive and negative results.


MATERIAL AND METHODS
Systematic and extensive literature search on the use of ultrasound (US) to predict thyroid cancer was conducted in the databases of Scopus, CINAHL (via EBSCO), MEDLINE (via PubMed), and Web of Science, covering the period from 2010 till 2021. The morphological features of thyroid nodules observed during the USG were analyzed based on Thyroid Imaging Reporting And Data System (TIRADS) guidelines. The accuracy of thyroid US was determined using parameters such as sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic ORs. Moreover, the respective forest plot and hierarchical summary receiver operating characteristics (HSROC) curve were plotted.


RESULTS
A total of 2765 reference studies were examined, and among them, 15 relevant references were selected. The selected studies were heterogeneous and included retrospective and prospective studies. The risk of publication bias is low as the p-value for both Egger's and Begg's tests is >0.05. The overall sensitivity of 92.53% (95% confidence interval (95% CI): [84.55%; 96.33%]), specificity of 33.88% (95% CI: [23.16%; 45.53%]) and diagnostic OR of 12.36 (95% CI: [3.90%; 54.11%]) are achieved. These results were statistically significant with a p-value < 0.001 and are predictive of US accuracy in detecting cancer.


CONCLUSION
The present meta-analysis, on the basis of statistically significant results, demonstrated the high accuracy of thyroid ultrasound in detection of malignant nature of nodules in patients suspected with a worrisome thyroid nodule.