An Increasing Clinical Problem
The importance of thyroid nodules rests in the malignant potential, according to Hatem El Halabi, MD, FACS, Director of Surgical Oncology at Virginia Hospital Center.
As defined by the American Thyroid Association (ATA), a thyroid nodule is a discrete lesion within the thyroid gland that is radiologically distinct from the surrounding thyroid parenchyma. Although a patient may see an enlargement or have other symptoms, more likely a nodule is discovered in a routine physical exam or when the patient has imaging for an unrelated condition.
A nodule >1 cm needs further evaluation. As per the ATA, a TSH and a neck ultrasound are the first two assessments. If the TSH is low, a radionuclide thyroid scan could be performed. A hot nodule is rarely malignant.
For patients with thyroid nodules >1 cm and with normal or elevated TSH; with nodules less than 1 cm but with suspicious features; or at high risk for thyroid cancer (see box on page 4), an ultrasound-guided fine needle aspiration (FNA), an office-based procedure, is the gold standard, said Dr. El Halabi.
Keep in Mind
- Five to 15% of the U.S. population has nodules in their thyroid.
- Of nodules that are 1 cm or larger, 8 to 15% prove to be malignant.
- An ultrasound and TSH are the first steps in evaluating a nodule.
- With tissue collected from a Fine Needle Aspiration, the Bethesda Criteria help the specialist recommend a course of action.
The Bethesda Criteria
In evaluating FNA results, specialists refer to the Bethesda Criteria:
- Nondiagnostic or unsatisfactory (in which case, the FNA is usually re-done)
- Benign (0–3% malignant)
- Atypia of undetermined significance or follicular lesion of undetermined significance (5–15% malignant)
- Follicular neoplasm or suspicions for a follicular neoplasm (15–30% malignant)
- Suspicious for malignancy (60–75% malignant)
- Malignant (97–99% malignant)
Mutational analysis and/or gene expression testing are now used with categories III–V to further delineate the malignant potential and sometimes alter the treatment plan.
The endocrinologist may refer the patient for a thyroidectomy after the initial evaluation. The surgeon could recommend a thyroid lobectomy or total thyroidectomy, depending on such factors as the clinical suspicion for malignancy, size of the nodule, and patient’s acceptance of the risk and benefit for either option.
Removing the thyroid carries the normal risks of surgery, a small chance of damaging the vocal cords and permanent hypocalcemia, and a lifetime of medication. New diagnostics mean more knowledge, so surgery is only performed when necessary.
According to Dr. El Halabi, these risk factors merit scrutinizing a thyroid nodule to rule out malignancy: (1) younger age, (2) male, (3) family history of thyroid cancer, (4) history of radiation exposure, (5) rapid growth or hoarseness, (6) thyroid cancer syndrome, like Cowden syndrome, multiple endocrine neoplasia, or familial polyposis.
Hatem El Halabi, MD, FACS, is the Director of Surgical Oncology at Virginia Hospital Center. He received his medical education from the American University of Beirut and completed his internship and residency at the Medical College of Virginia. He had fellowships at Mercy Health Services in Baltimore and the Medical Informatics and Telemedicine Applications Consortium in Richmond. He is board-certified and active in many professional societies as a presenter and author.