A new test developed by South San Francisco-based diagnostics company Veracyte promises to reduce the number of unnecessary thyroid cancer surgeries by more than half – that’s about 25,000 surgeries a year.
It’s called the Afirma Gene Expression Classifier. And by evaluating the activities of over 100 genes, it can determine whether a thyroid sample is benign or suspect.
Thyroid lumps (or nodules) are common and most are benign, but up to 15% are malignant. So for further examination, doctors usually recommend a minimally invasive procedure for extracting cells called fine needle aspirate (FNA) sampling.
That technique can accurately classify up to 85% as benign – but unfortunately, it produces indeterminate results in 15-30% of the cases, or nearly 100,000 people a year.
Currently, patients with ‘cytologically indeterminate’ thyroid nodules are usually referred for thyroid surgery to ensure that thyroid cancer is not present, says study researcher Erik Alexander of Brigham and Women’s Hospital in a press release.
While the majority will prove to be benign, these patients end up losing some or all of their thyroid in an expensive, invasive surgery. And they have to stay on hormone therapy for the rest of their lives.
With this new test, those thyroid nodule FNA samples that were originally deemed inconclusive can reclassified as ‘benign’ with a high degree of accuracy.
In a 2-year study involving 3,789 patients and 265 indeterminate thyroid FNA samples, the test predicted benign results accurately in about 94% of the samples.
“Nobody wants surgery if they don’t need it,” Alexander says. “This test, when it returns with a benign result, implies there is a very small risk of any cancer.”
Veracyte’s test, which costs about $3,500, is covered for Medicare patients and has become clinically available across the US in the last year. It’s being promoted globally by Sanofi’s Genzyme unit.
The study was published online in the New England Journal of Medicine today.