CONTROVERSIES IN THE MANAGEMENT OF COLD, HOT, AND OCCULT THYROID-NODULES

Some aspects of thyroid nodule evaluation and management remain contro versial. Radionuclide scanning provides functional information about n odules and differentiates cold from hot: nodules. Although thyroid can cers are cold on scan, most cold nodules are benign. Ultrasonography v isualizes the thyroid gland and nodules with remarkable clarity and pr ovides structural information about location, number, size, and consis tency of nodules. Widespread application of ultrasonography has result ed in the frequent discovery of incidental (occult) nodules in the gen eral population. The clinical significance of these nodules remains un known, and their management has created a dilemma for physicians. Curr ent cost-effective evaluation of nodules does not include scanning or ultrasonography as routine frontline tests. In most centers, fine-need le aspiration biopsy has supplanted imaging studies as the routine ini tial procedure for differentiating benign from malignant nodules. Cyto logic diagnosis is reliable and inexpensive, and it results in a bette r selection of patients for surgery. Limitations include false-negativ e diagnoses, nondiagnostic results, and indeterminate ''suspicious'' r esults. Laboratory test results are usually normal, but determination of serum thyrotropin may identify a hot nodule, and plasma calcitonin may help diagnose medullary thyroid carcinoma. Treatment of thyroid no dules is controversial. In some practices, benign colloid nodules are treated with suppressive doses of levothyroxine. Recent reports cast d oubt: on the efficacy of this approach, and it is no longer acceptable to select patients for surgical treatment on the basis of suppressive therapy. Furthermore, suppressive levothyroxine therapy may be associ ated with significant bone and cardiac side effects, especially in eld erly patients and postmenopausal women. Our approach is observation fo r most patients, and we suggest a careful risk-benefit analysis when s uppression is considered. Hot (autonomous) nodules can be treated with radioiodine, surgery, or ethanol injection. The use of sensitive thyr otropin assays has revealed that the ''euthyroid'' hot nodule is often associated with subclinical hyperthyroidism, warranting treatment a r isks of osteoporosis are significant. Small (less than or equal to 1.5 cm) occult nodules can be observed. Larger (> 1.5 cm) nodules can be selectively evaluated by ultrasonographically guided fine-needle aspir ation. It is prudent to consider cost of care, risk-benefit analysis, and the low incidence of malignancy in thyroid nodules when diagnostic tests are selected and the treatment plan is outlined.