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Risk of Malignancy (ROM) in the various categories of the UK Royal College of Pathologists thy terminology for thyroid FNAC cytology: a systematic review and meta-analysis

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Background - The UK Royal College of Pathologists Thy terminology for reporting thyroid FNAC cytology was first published in 2009, used throughout the United Kingdom and Ireland, in some parts of Italy and Switzerland, and elsewhere. There is no review of the literature or meta-analysis of the risk of malignancy (ROM) in the various categories of the UK Thy terminology. The study goal was to establish the published ROM for each Thy category and compare results with other existing terminology systems where similar meta-analyses were available.

Methods - A comprehensive literature search of online databases was conducted in May 2019 examining the ROM for histologically proven nodules with preoperative FNAC classified according to the UK Thy terminology.

Results - 25 articles were identified showing results of both cytology and histology. 12 of these were excluded to prevent selection bias as they showed data in just one Thy category. In the remaining 13 articles the pooled ROM was as follows; Thy 1: 12% (± 5-22%;95% CI); Thy 2: 5% (± 3-9%;95% CI); Thy 3: 22% (± 18-26%;95% CI); Thy 3a: 25% (± 20-31%;95% CI); Thy 3f: 31% (± 24-39%;95% CI); Thy 4: 79% (± 70-87%;95% CI); and Thy 5: 98% (± 97-99%; 95% CI) .

- This meta-analysis shows comparable results to meta-analyses of other internationally recognised reporting terminologies for pooled risk of malignancy for surgically excised nodules in the various Thy reporting categories. There is comparatively little difference (6% only) between the pooled ROM of Thy 3a and Thy 3f surgically excised nodules.
Original languageEnglish
Pages (from-to)36-42
Number of pages7
JournalCancer Cytopathology
Issue number1
Early online date13 Nov 2019
Publication statusPublished - 1 Jan 2020


  • Risk of Malignancy

    Rights statement: This is the peer reviewed version of the following article: Poller, D.N., Bongiovanni, M. and Trimboli, P. (2020), Risk of malignancy in the various categories of the UK Royal College of Pathologists Thy terminology for thyroid FNA cytology: A systematic review and meta‐analysis. Cancer Cytopathology, 128: 36-42, which has been published in final form at doi:10.1002/cncy.22201. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

    Accepted author manuscript (Post-print), 643 KB, PDF document

    Due to publisher’s copyright restrictions, this document is not freely available to download from this website until: 13/11/20

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