Most thyroid nodules — about 95 percent — are entirely benign. Identifying the occasional thyroid cancer, however, requires careful evaluation of every nodule found, using a combination of clinical assessment, neck palpation, ultrasound imaging, and, in many cases, analysis of a biopsy specimen.
Sometimes, thyroid nodules are noticed by the patient or a family member or are discovered during a routine physical examination. They rarely cause symptoms, unless they are large enough to interfere with swallowing.
Thyroid cancer can invade and damage the recurrent laryngeal nerve, causing hoarseness. Such invasion and damage are infrequent, however. Most nodules are incidental discoveries, and now many more such nodules are discovered because of the increased use of imaging performed for other reasons, including:
Early and prompt diagnosis improves the likelihood that a cancer can be discovered while still contained within the thyroid gland and amenable to surgery. Once soft tissue invasion has occurred or lymph nodes are extensively involved, the chance of surgical cure drops substantially and there is a much higher incidence of metastatic spread of these late-stage cancers. Prompt diagnosis is also important for the patient because the finding of a nodule often raises fears about cancer and a delay in diagnosis fuels the concern and anxiety.
The most recent set of guidelines from the American Thyroid Association specifies that the evaluation of a thyroid nodule should include clinical assessment to determine:
Not every nodule needs to be biopsied, however, so the clinical scenario and ultrasound features are important in selecting the appropriate nodule for biopsy.
Mayo Clinic endocrinologists opened the Thyroid Nodule Clinic in 2009 to streamline this evaluation and provide a coordinated approach that meets the needs of patients with thyroid nodules. The Thyroid Nodule Clinic provides a one-stop thyroid nodule evaluation that includes a focused clinical assessment, ultrasound evaluation, and FNA — all typically performed within a 60-minute appointment.
The ultrasound allows Mayo staff to select both palpable and impalpable nodules for biopsy and target the most suspicious nodule, which is not always the largest nodule. Using ultrasound guidance for those biopsies, Mayo Clinic endocrinologists typically perform more than 600 biopsies per year and expect a clear diagnosis in more than 95 percent of cases at the first attempt.
Because of the coordinated assessment provided through the Thyroid Nodule Clinic, FNA results are typically available within 2 hours, so the patient usually receives a definitive result of the entire assessment within 4 hours. Patients with a benign nodule can be reassured, and those with a malignant or suspicious nodule can be offered an appropriate surgical referral, often within 24 hours.
Mayo Clinic endocrinologists believe that the Thyroid Nodule Clinic improves the care they provide for these patients, while lowering costs, improving efficiency, and providing a better service to referring physicians.