Performance of Italian Consensus for the Classification and Reporting of Thyroid Cytology (ICCRTC) in discriminating indeterminate lesions at low and high risk of malignancy. A systematic review and meta-analysis

Background: Italian consensus for the classification and reporting of thyroid cytology was published in 2014 and it has been used in almost all Italian institutions. To date, there are not solid data on the reliability of Italian consensus for the classification and reporting of thyroid cytology in classifying low and high risk indeterminate nodules (Tir 3A and Tir 3B, respectively). Here, we reviewed and meta-analyzed the results of published articles to obtain evidence-based information on this topic. Research design and methods: A comprehensive literature exploration of online databases was conducted by searching all published papers citing Italian consensus for the classification and reporting of thyroid cytology. The search was updated until June 2017, and references of the retrieved articles were also screened. Only original articles reporting histologic follow-up of nodules cytologically classified as Tir 3A and Tir 3B were eligible for inclusion. Results: The literature search revealed 62 articles and six of these were eligible for the study. All papers were retrospective and published very recently. Overall, 423 indeterminate lesions, of which 180 Tir 3A and 243 Tir 3B, were found. Of these, 29 cancers were recorded in Tir 3A and 127 in Tir 3B. The pooled rate of malignancy was 17% (95% CI = 12 to 22%) in Tir 3A and 52% (95% CI = 46 to 58%) in Tir 3B. No significant publication bias was evident. Conclusions: Italian consensus for the classification and reporting of thyroid cytology 2014 shows high reliability in discriminating indeterminate lesions at low risk of malignancy from those at high risk.