Patients with benign thyroid nodules require follow-up because of a 5% rate of false negative FNA results. Although benign nodules may decrease in size, they do so slowly, and size is not an indication of the potential for malignancy. Follow-up should consist of serial ultrasonography.
Explore This IssueDecember 2007
In terms of medical therapy, routine suppression of serum TSH for benign thyroid nodules is not recommended, but such nodules can be excised if they enlarge and if there is reason for clinical concern.
For indeterminate biopsies, surgery is generally recommended, since the rate of malignancy is 15% to 20%. Lobectomy is appropriate for patients who prefer a limited procedure. For a large tumor, total thyroidectomy is indicated to prevent the need for reoperation in the event the tumor is malignant.
Nondiagnostic biopsies need to be repeated, preferably with ultrasound guidance. Cystic nodules that repeatedly yield nondiagnostic aspirates need close observation or surgical excision. For repeatedly nondiagnostic biopsies of solid nodules, surgery or observation are both appropriate.
For a biopsy diagnostic of malignancy, near-total or total thyroidecomy is the procedure of choice, unless (1) the tumor is less than 1 cm in diameter and completely confined to the thyroid, (2) there is no evidence of ipsilateral adenopathy on ultrasound, and (3) there is no family history of thyroid disease or history of head and neck irradiation. In such cases, lobectomy may be appropriate. Some experts, including the American Thyroid Association, recommend routine central neck dissection for patients with biopsy-proven thyroid cancer, but this remains controversial.
Differentiated Thyroid Cancer
Goals of differentiated thyroid cancer therapy include:
- Removal of the primary tumor, disease that has extended beyond the thyroid capsule, and involved cervical lymph nodes.
- Minimization of treatment- and disease-related morbidity.
- Accurate staging.
- Postoperative treatment with radioactive iodine, where appropriate.
- Accurate long-term surveillance for disease recurrence with radioiodine whole-body scanning and measurement of serum thyroglobulin.
- Minimization of the risk of disease recurrence and metastatic spread, most importantly by means of adequate surgery and adjunctive treatment.
Preoperative staging should be done by neck ultrasound, because 20% to 50% of papillary carcinomas spread to cervical lymph nodes. Frequency of micrometastases can be as high as 90%, and preoperative ultrasound can identify suspicious cervical adenopathy in about 25% of cases. Moreover, accurate staging is important in determining prognosis and tailoring individual treatment. However, the presence of metastatic disease does not obviate the need for surgical excision of the primary tumor, because metastatic disease can respond to radioiodine therapy. In such cases, because locoregional disease is an important component, it is important to remove the entire thyroid gland in addition to the primary tumor. The American Thyroid Association guidelines do not recommend routine neck CT or MRI for preoperative evaluation. Iodinated contrast should be avoided, as it will interfere with postoperative radioiodine therapy.