Supervised sonographer thyroid biopsies: non-diagnostic rate fell to 8.6%

Design

Retrospective single-centre quality-improvement study with contemporaneous comparison

Population

14,127 thyroid nodules biopsied in radiology, 2008–2022

Primary outcome

Non-diagnostic rate and malignant yield (Bethesda)

Effect

Non-diagnostic 34% → 8.6% (P<.001); late period sonographer 8.6% vs other clinicians 29%

A retrospective quality-improvement study at one academic centre reviewed 14,127 thyroid nodules biopsied by radiology between 2008 and 2022. A structured training programme for sonographers to perform fine-needle aspiration under radiologist supervision began in 2011.

Non-diagnostic results fell from 34% before the programme to 21% in its early years and 8.6% from 2014 to 2022. Malignant cytology rose from 4.9% to 7.7%, and combined Bethesda V/VI results from 8.9% to 12.1%. In the later period, sonographer biopsies had far fewer non-diagnostic results than those done by other clinicians in the same centre (8.6% vs 29%) and a higher malignant yield (7.6% vs 4.5%).

This is a before-and-after study at one centre, with a contemporaneous but not randomised comparison, so case mix and other changes over 14 years could contribute. The size and consistency of the effect still make a strong case that concentrating thyroid biopsies in a small group of trained, high-volume operators improves adequacy, whatever their professional background.

• Consider concentrating thyroid FNA in a small group of trained, high-volume operators.
• Track non-diagnostic and malignant yield by operator as quality measures.
• Build structured training and radiologist supervision into any delegation of biopsies.
• Expect adequacy to improve over years, not months; the rate kept falling after the early period.

Why it matters

Non-diagnostic thyroid biopsies are common, and this shows how much of the problem is operator volume and training.

Don't overread it

A single-centre before-and-after study — case mix and other changes over 14 years may contribute.

The statistics, in plain English

A fall from 34% to 8.6% means about one in four nodules was spared a repeat biopsy. The comparison with other clinicians in the same years helps rule out a simple time trend, but it was not randomised.

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