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Fine Needle Aspiration FNA Biopsy of the Thyroid

Questions & Answers


Updated June 02, 2014

Fine Needle Aspiration FNA Biopsy of the Thyroid

Fine needle aspiration biopsy is used to help determine if thyroid nodules are cancerous.

Will It Hurt?

That depends on the skill of the practitioner, your own perceptions of pain. Some practitioners will use lidocaine, a local anesthetic, to numb the injection site. But patients complain that this can hurt more than the actual FNA procedure. Other practitioners don't use anesthetic. At a ThyCa conference, Dr. Oertel explained that she does not use an anesthetic, she prefers to use an ice pack to numb the skin. Her rationale - an anesthetic needle creates a lump - some swelling - around the injection site that can interfere with the ability to get an accurate sample.

How Will it Feel Afterwards?

You might have slight pain with some swelling and bruising at the injection locations, and possibly slight discomfort in swallowing. Ask your doctor about recommendations regarding post-FNA pain medication - many recommend taking acetominophen or ibuprofen as directed to minimize any residual discomfort.

Can You Go Back to Work?

Most people are comfortable enough to go back to work the same day or next day after having an FNA.

But you should avoid vigorous physical activity and sports for approximately 24 hours after the FNA.

What Kind of Results Can You Expect?

A nodule is more likely to be cancerous if it falls into certain risk factors:

  • Larger nodules - over 4 centimeters, are more likely to be cancerous than nodules less than 4 centimeters
  • Men's nodules are more likely to be cancerous than women's nodules, however nodules in pregnant women are more likely to be cancerous than nodules in a non-pregnant woman
  • A solitary nodule is more likely to be cancerous than nodules found in a "multinodular" thyroid
  • Nodules in a person younger than 20 or older than 70
  • History of external neck irradiation during childhood
  • "Cold" characterization on ultrasound - meaning that the nodule does not absorb iodine or make thyroid hormone
Ultimately, however, approximately 5% of all thyroid nodules are cancerous.

What If It's Benign?

If you have a benign nodule, your doctor will likely treat the nodule. For more information, see my article, Thyroid Nodules, Lumps and Goiters as your starting point.

What If It's Malignant/Cancerous?

If you are diagnosed with thyroid cancer, your first stop should be the following article, An Introduction to Thyroid Cancer, which is a good starting point for information about thyroid cancer, including papillary, follicular, medullary and anaplastic cancer, including support groups and followup treatments.

Your next step should be to join the Thyroid Cancer Survivor's Association, and to take advantage of their many patient support services.

What If It's Inconclusive or Indeterminate?

If a nodule is inconclusive, in the past, physicians have recommended surgery to remove all or part of the thyroid. Only 20 to 30% of inconclusive or indeterminate nodules are cancerous, however. This results in many unnecessary surgeries, along with lifelong hypothyroidism for many of those patients post-surgery. A test released in 2011, the Afirma Thyroid FNA Analysis process, developed by Veracyte, prevents inconclusive/indeterminate results for nodules, thereby offering more definitive FNA results, and preventing the need for surgery in the estimated 70 to 80% of patients who have inconclusive/indeterminate nodules, but no cancer.

Can You Have a False Diagnosis?

False results, such as false negatives showing your FNA results are benign when they are actually cancerous, or false positives showing a benign nodule as malignant, are more common than you think. Some experts estimate that an average of approximately 2 to 4% of all FNAs may be false results.

Do You Need a Second Opinion?

If you have a negative result, but have risk factors for or family history of thyroid cancer, in particular, you should consider getting a second opinion on your FNA. And, if you have a positive result indicating cancer, a second opinion is also important. And if you have inconclusive or indeterminate findings and have not had the FNA tested using the Afirma Thyroid FNA Analysis process, you may want to have that test done to assess the nodule definitively before undergoing surgery.

You may feel uncomfortable about mentioning this to your doctor, or feel that it will be perceived negatively by your doctor, but, as Dr. Oertel said in her presentation to the ThyCa conference, "Get a second opinion. My ego will recover, but you might not!"

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