Screening for differentiated thyroid cancer in selected populations.

The main purpose of cancer screening programmes should not be to detect all cancers, but to discover potentially fatal or clinically relevant cancers. The US Preventive Services Task Force recommends against screening for thyroid cancer in the general, asymptomatic adult population, as such screening would result in harms that outweigh any potential benefits. This recommendation does not apply to patients with symptoms or to individuals at increased risk of thyroid cancer because of a history of exposure to ionising radiation (in childhood, as radioactive fallout, or in medical treatment as low-dose radiotherapy for benign conditions or high-dose radiation for malignancy), inherited genetic syndromes associated with thyroid cancer (eg, familial adenomatous polyposis), or one or more first-degree relatives with a history of thyroid cancer. We discuss the evidence for and against screening individuals who are at high risk, and consider the different screening tools available.