Dr. R. Mack Harrell is co-founder of the Memorial Center for Integrative Endocrine Surgery in Hollywood, Weston and Boca Raton, Florida. He is a past President of the American Association of Clinical Endocrinologists and President-Elect of the American College of Endocrinology. His practice has been using the Afirma® Gene Expression Classifier (GEC) for its thyroid nodule patients since January 2011 – shortly after the genomic test became clinically available. He spoke with us about a study that evaluated the long-term impact of the test’s use on patient care.
Q: Why was it important to look at Afirma GEC results over the last six years?
Dr. Harrell: We wanted to assess the Afirma GEC’s rates of benign and suspicious results on indeterminate thyroid nodules and gauge how many surgeries the test has prevented over that time frame. We thought it was especially important to establish this baseline as Veracyte is developing a new version of the test – with higher specificity.
Q: How did you do this and what did you find?
Dr. Harrell: Veracyte pulled results for all Afirma GEC tests run between January 1, 2011 and September 30, 2016. We also did a literature search for articles from the same period, which reported surgical rates for the Afirma GEC benign and suspicious nodules. We found that the genomic test called 45 percent of the indeterminate samples benign. Based on reported subsequent surgical rates, we estimated that over 90 percent of those Afirma GEC benign cases avoided surgery.
Q: What is most noteworthy to you about these findings?
Dr. Harrell: They tell us that physicians are respecting the determination of the Afirma GEC and that, in general, long-term follow-up of GEC benign patients does not lead to surgical events. If the GEC result is benign, then in more than 90 percent of these cases, physicians are not sending the patient to surgery. So, the test is reducing surgeries and costs as it was designed to do.
Q: What about the 10 percent who still undergo surgery?
Dr. Harrell: This rate is similar to the rate of patients with cytopathology-benign results who eventually undergo thyroid surgery. In either case, the reason is usually due to large or increasing nodule size, compression symptoms or other clinical factors. The fact that 10% are still undergoing surgery is reassuring to me because it shows doctors are still taking care of the whole patient. They’re not blindly following the Afirma GEC results. Rather, they’re still tracking these Afirma GEC benign patients with ultrasound, as they should be doing according to protocols created by sub-specialty societies like AACE with the input of professional thyroid experts.
Q: What is the key takeaway from these findings for your peers?
Dr. Harrell: The Afirma GEC is having the desired impact on patient care. Increasing the test’s specificity will be an important advance because it should help to reduce surgeries for benign disease and thereby decrease unnecessary costs even further.