Abstract
Background: Strain and shear wave elastography (SWE) which is commonly used with concurrent real-time imaging known as real time ultrasound shear/strain wave elastography (USE) are new diagnostic techniques that have been reported to be useful in the diagnosis of nodules in several organs. There is conflicting evidence regarding its benefit over US-FNAC alone in thyroid nodules.
Objectives: To determine if ultrasound Strain and shear wave elastography (USE) in conjunction with fine needle aspiration cytology (FNAC) will reduce the number of patients who have a non-diagnostic first FNAC results as compared to conventional ultrasound (US) only guided FNAC.
Design: A pragmatic, unblinded, multi-centre randomised controlled trial.
Setting: 18 centres with a radiology department across England.
Participants: Adults who had not undergone previous FNAC with single or multiple nodules undergoing investigation.
Interventions: USE-US guided FNAC (Intervention arm) – Strain or shear wave elastography (USE)-guided FNAC.
US-only guided FNAC (Control arm) – Routine US-only guided FNAC (the current standard recommended by the British Thyroid Association guidelines).
Main outcome measure: The proportion of patients who have a non-diagnostic cytology (Thy 1) result following the first FNAC.
Randomisation: Patients were randomised at a 1:1 ratio to the interventional or control arms.
Results: A total of 982 participants (80% female) were randomised: 493 were randomised to USE-US guided FNAC and 489 were randomised to US-only guided FNAC. There was no evidence of a difference between USE and US in non-diagnostic cytology (Thy 1) rate following the first FNAC (19% vs 16% respectively; risk difference (RD): 0.030; 95% C.I: -0.007 to 0.066; p=0.11), the number of FNACs needed (Odds Ratio (OR): 1.10; 95% C.I: 0.82 to 1.49; p=0.53) or in the time to reach a definitive diagnosis (Hazard Ratio (HR): 0.94; 95% C.I: 0.81 to 1.10; p=0.45). There was a small, non-significant reduction in number of thyroid operations undertaken when USE was used (37% vs 40% respectively; RD: -0.02; 95% C.I: -0.06 to 0.009; p= 0.15), but no difference in the number of operations yielding benign histology - 23% vs 24% respectively, p = 0.70 (i.e. no increase in identification of malignant cases) - or in the number of serious adverse events (SAEs) (2 vs 1%). There was no difference in anxiety and depression, pain or quality of life between the two arms.
Limitations: Study was not powered to detect differences in malignancy.
Future work: The findings of the Elation trial suggest that further research into the use of shear wave elastography in the diagnostic setting of thyroid nodules is unlikely to be warranted, unless there are improvements in the technology. The diagnostic difficulty in distinguishing between benign and malignant lesions, still persist. Future studies might examine the role of genomic testing on FNA samples. There is growing use of targeted panels of molecular markers, particularly aimed at improving the diagnostic accuracy of indeterminate (i.e. Thy3) cytology results. The application of these tests is not uniform, and their cost effectiveness has not been assessed in large scale trials.
Objectives: To determine if ultrasound Strain and shear wave elastography (USE) in conjunction with fine needle aspiration cytology (FNAC) will reduce the number of patients who have a non-diagnostic first FNAC results as compared to conventional ultrasound (US) only guided FNAC.
Design: A pragmatic, unblinded, multi-centre randomised controlled trial.
Setting: 18 centres with a radiology department across England.
Participants: Adults who had not undergone previous FNAC with single or multiple nodules undergoing investigation.
Interventions: USE-US guided FNAC (Intervention arm) – Strain or shear wave elastography (USE)-guided FNAC.
US-only guided FNAC (Control arm) – Routine US-only guided FNAC (the current standard recommended by the British Thyroid Association guidelines).
Main outcome measure: The proportion of patients who have a non-diagnostic cytology (Thy 1) result following the first FNAC.
Randomisation: Patients were randomised at a 1:1 ratio to the interventional or control arms.
Results: A total of 982 participants (80% female) were randomised: 493 were randomised to USE-US guided FNAC and 489 were randomised to US-only guided FNAC. There was no evidence of a difference between USE and US in non-diagnostic cytology (Thy 1) rate following the first FNAC (19% vs 16% respectively; risk difference (RD): 0.030; 95% C.I: -0.007 to 0.066; p=0.11), the number of FNACs needed (Odds Ratio (OR): 1.10; 95% C.I: 0.82 to 1.49; p=0.53) or in the time to reach a definitive diagnosis (Hazard Ratio (HR): 0.94; 95% C.I: 0.81 to 1.10; p=0.45). There was a small, non-significant reduction in number of thyroid operations undertaken when USE was used (37% vs 40% respectively; RD: -0.02; 95% C.I: -0.06 to 0.009; p= 0.15), but no difference in the number of operations yielding benign histology - 23% vs 24% respectively, p = 0.70 (i.e. no increase in identification of malignant cases) - or in the number of serious adverse events (SAEs) (2 vs 1%). There was no difference in anxiety and depression, pain or quality of life between the two arms.
Limitations: Study was not powered to detect differences in malignancy.
Future work: The findings of the Elation trial suggest that further research into the use of shear wave elastography in the diagnostic setting of thyroid nodules is unlikely to be warranted, unless there are improvements in the technology. The diagnostic difficulty in distinguishing between benign and malignant lesions, still persist. Future studies might examine the role of genomic testing on FNA samples. There is growing use of targeted panels of molecular markers, particularly aimed at improving the diagnostic accuracy of indeterminate (i.e. Thy3) cytology results. The application of these tests is not uniform, and their cost effectiveness has not been assessed in large scale trials.
| Original language | English |
|---|---|
| Journal | Health Technology Assessment |
| Publication status | Accepted/In press - 4 May 2023 |
