Radioiodine Therapy of Non-Toxic Goiter

Abstract

Euthyroid sporadic nodular goiter is the diagnosis in the majority of our iodine-replete goitrous adult population. Sporadic nodular goiter is derived from the natural heterogeneity of thyroid follicular cells, which, when amplified by yet unidentified trophic stimuli, results in episodes of proliferating, rapidly dividing micronodules. With time, diffuse goiters develop and evolve into a nodular configuration associated with rapid growth, hemorrhagic necrosis, and reparative fibrosis that accentuate goiter nodularity. Diagnostic evaluation is comprised of history and physical examination, seram thyrotropin and free thyronine, and selected imaging studies assessing goiter size, anatomy and function. If treatment is required, L-thyroxine suppression, surgery, and radioiodine are effective in properly selected patients. L-thyroxine reduces goiter size in 58% of patients with a mean decrease in goiter volume of 25%, but therapy must be continued to prevent regrowth. Surgery promptly reduces goiter volume and relieves compressive symptomatology, but some patients are not surgical candidates or refuse surgical intervention. Radioiodine (1–131) can deliver 10–25 thousand rads to multinodular goiters decreasing goiter volume and relieving compressive symptomatology. In prospective European series delivering 100–125 uCi/gm of goitrous tissue, significant responses have been seen in >90% of patients. Similar patients can be treated effectively in the United States as outpatients.