Screening for differentiated thyroid cancer in selected populations

Cancer screening programes should aim to discover potentially fatal or clinically relevant cancers, their main

endpoint being the reduction of cancer-specific mortality  since other derivative or surrogate endpoints can be misleading. Although some programes might seem beneficial because they increase the length of life, this increase can appear because of potentially deceptive effects, such as the lead time bias and length time bias.

All screening programes  have potential benefits

and risks. According to WHO, early detection activities are justified if: the candidate cancers are frequently occurring ;a high proportion of patients present in advanced stages; cost-effective, early detection methods are available and easily accessible for the group at risk; diagnosis, treatment follow-up, and quality assurance procedures can be implemented; and the benefits of early detection outweigh the risks, in terms of complications and negative effects.

Medullary thyroid cancer

Among the thyroid cancers, medullary thyroid cancer offers a unique model of a targeted and effective screening strategy, since a genetic test with direct clinical application is available

The American Thyroid

Association guidelines recommend that all patients with

medullary thyroid cancer undergo genetic testing to

detect a possible germline RET mutation. In fact, 1–7%

of patients with medullary thyroid cancer that is believed

to be sporadic have a hereditary disease.

If a RET

mutation is found, genetic counselling and genetic

testing for RET germline mutations should be offered to

first-degree relatives of the patient, and only those with

the mutation will undergo further investigations. The

specific mutation that is found can also direct the timing

of therapy or the intensity of surveillance, or both