Molecular testing is now recommended as part of the workup for indeterminate thyroid nodules (Bethesda III-IV) and results in fewer unnecessary thyroid surgeries. Thyroseq is a commercially available genomic classifier test that utilises next generation sequencing to analyse DNA and RNA of 112 thyroid-related genes. It is reported to have both high NPV (97%) and PPV (66%), with 84% sensitivity and 82% specificity. Currently, testing is provided by UPMC, Pittsburgh, USA.
Referral of selected cases with indeterminate FNA cytology for ThyroSeq testing was introduced in CUH cytology department in December 2022. 16 patient samples have been tested to date. These include 5 males and 11 females, mean age 56 years.
Of 16 samples submitted; 3 results are pending, insufficient n=4, negative n=1, low risk n=7, high risk n=1. Only the patient with high risk ThyroSeq underwent surgery, which was follicular variant of PTC on histology. All low risk and negative patients (n=8) avoided surgery and are undergoing surveillance.
Testing is funded by the HSE and although the cost per test seems high (approximately 2,000 USD), these initial results suggest a significant overall cost saving, with reduction in morbidity and avoidance of unnecessary surgery.
Julie McCarthy1, H Paul Redmond2, Andrew Dias3, Linda Feeley1,4, Patrick Sheahan3,4
1 Department of Pathology, Cork University Hospital, Cork
2 Department of Surgery, Cork University Hospital, Cork
3 Department of Otolaryngology Head & Neck Surgery, South Infirmary Victoria University Hospital, Cork
4 ENTO Research Unit, College of Medicine and Health, University College Cork, Cork