Genetic Testing and Screening in Advanced MTC

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Genetic testing and screening is equally important for both early and advanced medullary thyroid cancer (MTC), explains Eric J. Sherman, MD. Testing not only aids the clinical management of patients but also the counseling of family members. In addition to genetic testing, Sherman adds, screening for MEN 2A- and 2B-related syndromes should include catecholamines and catecholamine metabolites. This type of screening is important for medical oncologists to understand, states R. Michael Tuttle, MD, since many patients with MTC are now bypassing endocrinologists.

A potential correlation between genotype and phenotype warrants the early detection of certain hereditary syndromes, explains Lori J. Wirth, MD. Mutations in MEN 2B are generally associated with the development of MTC at a very young age. As such, the detection of this mutation warrants early intervention, including thyroidectomy for children as young as 1-year-old.

Patients with sporadic MTC who harbor mutations in certain genes may have a worse prognosis, explains Wirth, specifically patients with M918T mutations in the RET oncogene. As a result, genetic testing remains important, regardless of the stage at presentation, for determining prognosis and risks.