The New Thyroid Cancer Test
Paul Aoun, DO, PhD, Endocrinologist at Palm Beach Diabetes & Endocrine Specialists, talks about a new genomic test to identify if a questionable thyroid nodule biopsy is benign or suspicious for cancer
What are the reasons that people come to check their thyroid?
Dr. Aoun: There are several reasons for which people come to have their thyroid checked. One is having symptoms and/or laboratory tests suggestive of either under or overproduction of thyroid hormones. Another reason is that people notice something in their neck such as a lump that upon further evaluation is determined to be a thyroid nodule, or growth in the thyroid gland.
How common are those nodules?
Dr. Aoun: Thyroid nodules are very common. In fact, among people over the age of fifty, fifty percent or more will have thyroid nodules. So, it’s more common to have thyroid nodules over that age than to not have thyroid nodules.
But what are they looking for, when you’re at home and you feel a lump? What is it you’re looking for exactly?
Dr. Aoun: The majority of thyroid nodules are not felt at home. They’re usually picked up by the physician during an exam or through something we call an incidental finding. That is when a CT scan or an ultrasound of the neck done for another reason, picks up a thyroid nodule.
So most of the time it’s something that they have no idea about?
Dr. Aoun: Exactly.
How dangerous can it get?
Dr. Aoun: It’s not very dangerous. The majority of nodules are small and benign. If they get too large to the point that they start causing compressive symptoms, such as pushing against the windpipe or the esophagus, then patients might experience changes in their voices or complain of food getting stuck in their throats.
So if it gets picked up by the exam you get a biopsy?
Dr. Aoun: The next step is to get an ultrasound and thyroid blood tests. If the thyroid function tests are okay and the nodule warrants being biopsied, I will then proceed to fine needle aspiration, or FNA.
So how invasive is this?
Dr. Aoun: It’s not very invasive. We clean the neck, spray some numbing medication, use a thin needle to get a few samples from the nodule and we send the collected cells for analysis.
What are usually the findings?
Dr. Aoun: There are four possible outcomes. It could come back as benign, which is the most common finding. A second possibility is malignant or suspicious for cancer. A third option is non-diagnostic, which means, the sample is suboptimal and thus a diagnosis cannot be made. In up to twenty to thirty percent of cases at most, we get inconclusive or indeterminate results, which means that the makeup of the nodule is not clear-cut to help make a definitive diagnosis.
So benign is good, it means that you’re good to go, no surgery.
Dr. Aoun: Correct, if the result is benign, then there is no need for surgery, and we usually continue to monitor those patients with serial ultrasounds, as needed. If a benign nodule gets too large and starts causing problems, then surgery is warranted. If the nodule is cancerous, then the recommended next step is surgery. If the FNA result is, non-diagnostic, we usually repeat the biopsy. For nodules with indeterminate findings, the traditional approach had been to send the patient to surgery. This recommendation, however, has been modified after cytogenetic testings, such as the Afirma test, have become available.
So what are you removing when you go in to surgery?
Dr. Aoun: Surgery has traditionally involved removing all or part of the thyroid.
How often do you perform the FNA, and do you perform it yourself?
Dr. Aoun: I do. I look at the ultrasound sonographic features of the nodule, take in-to consideration the patient’s clinical risk factors, such as radiation exposure or family history of thyroid cancer, and decide accordingly on whether to proceed to FNA.
So how often do you do it here yourself? How many have you done so far?
Dr. Aoun: I’ve done several. I can’t give you an exact number, but I can tell you that about half a million nodules or so get biopsied on a yearly basis in the U.S..
From those half a million how often do they come out inconclusive?
Dr. Aoun: If we consider a twenty percent cut-off, that would be about a hundred thousand indeterminate biopsies per year.
So a hundred thousand people are actually going in to surgery not knowing if they need to or not?
Dr. Aoun: On pathology analysis after surgery, about seventy-five percent of those with indeterminate nodules will end up having a benign disease. Only twenty-five percent or so will turn out to have cancer.
So they’re going through this process of surgery. For patients, what is the recovery time, what do they go through, and how does that change their life?
Dr. Aoun: There is a lifelong requirement for thyroid hormone replacement therapy if the whole thyroid is removed. Also, one must factor in the potential risks of surgery.
How invasive is the surgery?
Dr. Aoun: An incision is done in the neck to remove part of or the whole thyroid. Recovery is fairly good. If the patient is stable and there are no complications, they usually go home the next day.
So now we have this test that’s called the Afirma Gene Expression Classifier?
Dr. Aoun: That is correct.
Can you explain what it does?
Dr. Aoun: The Afirma gene expression classifier comes in-to play when a patient has an indeterminate thyroid nodule FNA. Traditionally, those patients were sent to surgery. Now the Afirma gene expression classifier helps sort out whether the nodule appears benign or not. If benign, the patient can avoid surgery and be monitored instead. If, however, the results of the genetic test are suspicious for cancer, we recommend that those patients still proceed to surgery.
How does it work exactly, how does it know?
Dr. Aoun: The genomic test looks at certain gene expression patterns in the indeterminate FNA sample to reclassify the nodule as benign or suspicious for cancer. When I do the biopsy, I take an extra sample to be analyzed in case the initial results are indeterminate. Thus, the Afirma test will be performed without the patient having to come back for another FNA. The overall goal is to help patients whose inconclusive nodules are actually benign to avoid surgery they would otherwise undergo.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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If you would like more information, please contact:
Dr. Paul Aoun, DO, PhD, Endocrinologist
Palm Beach Diabetes & Endocrine Specialists
To read the full report, Avoiding Unnecessary Surgeries: New Thyroid Cancer Test, click here.