The Assessment of Thyroid Nodules

The assessment of a thyroid nodule serves several purposes. The patient may experience symptoms from a functional or sizable lesion, or may be at risk of cancer. A thorough history and blood test for TSH, eventually combined with a technetium (Tc) scan, will promptly identify a hyperfunctioning nodule. Symptoms related to the size of a nodule are usually indicated by the patient, and may be crucial in the treatment-making process. Determining the risk of cancer in a nodule can be a more difficult concept, and the approach involves medical, rational, economic, and cultural considerations. It should be remembered that in dealing with a thyroid nodule, the evidence with regard to outcome, including the prevention of death, and morbidity, from thyroid cancer, is sparse. The natural course of a microcancer or small cancer is not known. They are both frequent findings in postmortem examinations that seem to have caused no morbidity to those who died from natural or other causes. Therefore neither common sense nor evidence supports the assumption that the health of a population or of an individual benefits from an overly aggressive approach to early or small cancers. For example; in the commonest cancer, papillary thyroid cancer (PTC), there is no evidence that treatment in the earliest stage offers a significant benefit compared with treatment at a slightly later point, when the increase in size of a suspicious nodule has provided evidence that the lesion is dynamically growing. In other words, while the patient may have a risk of cancer, indeed even in the presence of cancer, it is important to avoid causing undue fear to patients, and harm from invasive or unnecessary investigations. The appropriate timing of the assessment for a suspect follicular thyroid cancer (FTC) is equally unclear but is complicated by the fact that undue delay may lead to a scenario where distant metastases have become established from early haematogenous spread. For the less common medullary thyroid cancer (MTC) there is overwhelming evidence that early detection and treatment results in an improved outcome. For anaplastic thyroid cancer (ATC) only early treatment provides a chance of survival. Based on the enormous variety of biological behaviors and clinical significance of the different forms of thyroid cancer we should question, what we hope to achieve, in assessing a thyroid nodule. Do we want to exclude all risk of cancer? (i.e., histologically classify every lesion).Or do we want to reduce the actual risks of cancer by detecting and treating those cancers, which have a likely or proven propensity to damage the patient? These questions are of both academic, and more importantly, practical relevance. The attempt to exclude all risk of cancer would require an algorithm that enables the fail-safe