Thyroid Cancer Diagnostic Testing

What is a Thyroid Gland?

The thyroid is a gland located in the neck and influences the body’s metabolic processes. Without a thyroid gland, a patient must take supplemental hormone therapy indefinitely to prevent hypothyroidism. As many as 54,500 new cases of thyroid cancer will be diagnosed in the United States in 2012.

Diagnosing Thyroid Cancer 

Quest Diagnostics, the world’s leading provider of diagnostic testing, information and services, offers a new molecular test panel designed to help physicians determine if a thyroid gland is cancerous and requires surgical removal. The test is believed to be the most comprehensive panel clinically available to identify mutations associated with four gene markers indicated by the American Thyroid Association’s guidelines for clinical management of indeterminate thyroid biopsies.

The Quest Diagnostics Thyroid Cancer Mutation Panel aids in assessing the likelihood of cancer in thyroid biopsies which are found to be indeterminate for cancer by current cytology test methods. Approximately 15% to 20% of these biopsies, which are collected by fine needle aspiration (FNA), produce indeterminate results. An unclear result may increase the risk that a physician, as a matter of caution, will biopsy additional tissue using a larger needle or surgically remove part or all of a thyroid suspected of being cancerous, that is later diagnosed as a healthy gland. About 300,000 thyroid FNA biopsy procedures are performed annually in the United States.

The new panel identifies mutations of the molecular markers BRAF V600E, RAS, RET/PTC, and PAX8/PPAR gamma, which are associated with papillary and follicular thyroid cancer, two common forms of the disease. Practice guidelines from the American Thyroid Association recommend that physicians consider these markers as aids in clinical management of patients with indeterminate biopsy test results.

Monitoring Recurrence 

In addition, Quest Diagnostics has introduced the Thyroglobulin (Tg) Post-treatment Monitoring Test to aid in monitoring for recurrence of cancer following surgery. Thyroid cancers can cause blood levels of Tg to rise, providing a marker for recurrence. However, these cancers can also cause auto-antibodies (anti-TG) to rise, hindering reliable Tg measurement in 20% to 30% of cases. The new Quest Diagnostics test is the first for clinical use to use liquid chromatography tandem mass spectrometry (LC/MS/MS), a highly sensitive analytical technique, to confirm and measure Tg in anti-TG positive specimens tested by immunoassays.