Endocrine Abstracts

Thyroid nodules and goitre are a common problem, with a very high prevalence evident from screening studies of the general population. In contrast, thyroid cancer is rare accounting for <1% of all new malignancies diagnosed in England and Wales each year. The challenge to the clinician is therefore to identify, amongst the large number of patients referred because of thyroid enlargement, the small proportion thyroid neoplasia. This differentiation is critical since most with non-neoplastic disease can be managed conservatively, or medically (e.g. with radioiodine), whereas those with neoplastic disease require surgical intervention.

Historically, isotope scanning has been used to investigate thyroid nodules. Numerous studies have, however, demonstrated the poor specificity of results so this test should be abandoned. Ultrasound imaging can also be used to investigate the nature of nodules/goitre; again findings are poorly specific in terms of sonographic findings indicating neoplasia. Future availability of new and improved ultrasonographic technology may change this conclusion but, at present, US scanning adds little to the routine work up of patients presenting with thyroid nodules.

The critical test in the diagnosis of thyroid neoplasia is fine needle aspiration cytology (FNAC) with large series, such as our own, indicating sensitivity and specificity for neoplastic disease of approximately 90%. National guidelines therefore indicate that this is the first line test of choice. Debate surrounds the question of whether improved accuracy can be achieved by using US guided FNAC compared with palpation guided; results of studies comparing these two approaches have failed to provide consistent evidence that US guidance is of significant value.

The syringe and needle are therefore the tools of choice!