Abstract 1745P
Background
According to the 2017 bethesda system for reporting thyroid cytopathology (BSRTC), a repeat FNA is recommended for cytologically ND/UNS nodules and some cytologically AUS/FLUS nodules as well. This study would explore correlation between molecular testing upon the first FNA and BSRTC class of repeated FNA (Re-FNA).
Methods
In the previous study, we conducted a prospective analysis of 383 thyroid nodule FNAB specimens evaluated using the BSRTC, and most of FNAB specimens underwent FSZ-Thyroid NGS Panel V1 molecular testing. Among them, 21 patients underwent repeated FNA, and the BSRTC class of Re-FNA and postoperative pathology (if any) were followed up.
Results
Among 21 patients who underwent Re-FNA, the BSRTC class of the first FNA was distributed in I (3, 14.3%), III (14, 66.7%) and IV (4, 19%), which accounted for 7.3% (3/41), 16.7% (14/84) and 25% (4/16) of corresponding BSRTC class, respectively. To be specific, 1 of 3 patients with BSRTC I nodules underwent upgrade to III upon repeated FNA; 11 of 14 BSRTC III nodules upgraded to V (3) and VI (8), respectively. As to BSRTC IV nodules, 1/4 upgraded to V upon repeated FNA. To explore the correlation between the result of molecular testing upon the first FNA and BSRTC class of repeated FNA, we made a contingency table (table) which showed that 90.9% (10/11) of patients with positive molecular testing result underwent upgrade of BSRTC class upon Re-FNA. As a comparation, only 30% (3/10) of patients with negative result underwent upgrade of BSRTC class. Interestingly, the only patient with a positive molecular testing result and non-upgrade of BSRTC class underwent surgery and the postoperative pathology of the patient was PTC. Table: 1745P
The contingency table
| Molecular Testing | Total | |||
| Positive | Negative | |||
| Re-FNA | Upgrade | 10 | 3 | 13 |
| Non-upgrade | 1 | 7 | 8 | |
| Total | 11 | 10 | 21 |
Note: Fisher's exact test p-value equals 0.0075.
Conclusions
Considering most upgrade being from III-IV to V-VI, the positive molecular testing result upon the first FNA might suggest not only the upgrade of BSRTC class upon repeated FNA but also necessity of surgery instead of Re-FNA in this situation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.