New Assay May Help Guide Therapy in Papillary Thyroid Cancer

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New Assay May Help Guide Therapy in Papillary Thyroid Cancer
New Assay May Help Guide Therapy in Papillary Thyroid Cancer

A novel blood assay that detects circulating BRAFV600E levels may be helpful in diagnosing and managing papillary thyroid cancer (PTC), new data presented at the 84th Annual Meeting of the American Thyroid Association suggest.

“Knowledge of BRAF status preoperatively could aid in surgical planning, prognosis and potentially as a surveillance tool,” said study investigator Carrie Lubitz, MD, MPH, of Massachusetts General Hospital, Boston, Massachusetts. 

“BRAF inhibitors have been effective in patients with melanoma and are under trial in advanced thyroid cancer. In the melanoma populations, who harbor the same mutation, the assay was able to detect recurrence prior to clinical or radiological recurrence. We believe this assay shows great promise.”

Dr. Lubitz, who presented the study findings at the meeting, said the experimental rapid assay has potential to be a more cost-effective method for diagnosing and monitoring patients with PTC.

Currently, she and her team are assessing its potential applications for lowering morbidity and mortality among patients with PTC. The BRAFV600E mutation is the most common genetic alteration in patients with PTC, and this mutation is associated with a poorer prognosis. BRAFV600E is also associated with resistance to radioiodine therapy.

For this study, Dr. Lubitz and her colleagues measured circulating BRAFV600E levels in blood samples from patients with PTC using the assay and compared the results with conventional BRAFV600E tissue assays.  

The researchers collected blood from patients with PTC before thyroidectomy and from a subset of patients with advanced disease known to be BRAF-positive. Those performing the blood assay were blinded to the patient's diagnosis and to BRAF status (by conventional assay). No patient had a history of colon cancer or melanoma.

The group included patients with stages I through IV disease. BRAF levels from the assay were correlated with tumor burden. In this analysis, there were 46 patients (PTC, 36 patients; other thyroid disorders, 10 patients). 

Data indicated that circulating BRAFV600E levels were detectable in the patients with PTC and that results correlated with conventional assays. The researchers also found that the threshold value for sensitivity was 62% and specificity was 90%.

Dr. Lubitz said the findings suggest that this novel assay may be useful for improving diagnosis, postoperative surveillance and for monitoring treatment response to BRAF inhibitors. 

“The assay is not currently commercially available,” Dr. Lubitz told Endocrinology Advisor. “BRAF mutant circulating tumor cells are detectable and the test has the potential to be a less invasive test.  It is a simple blood draw and can been used serially. That is really the take-home message from the study.”

Reference

  1. Lubitz CC et al. Oral Abstract 122. Presented at: American Thyroid Association (ATA) 84th Annual Meeting; Oct. 29-Nov. 2, 2014; Coronado, Calif.
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