Radioiodine Strategies in the Management of Well Differentiated Thyroid Cancer

The initial treatment of well differentiated thyroid cancer (papillary and follicular thyroid cancer) is surgical and depending upon the extent of surgery, there is often residual tumor or normal thyroid remnants remaining in the thyroid bed. Radioiodine ablation of such tissue is an essential first step in preparation for further treatment of metastases or long-term monitoring. The prognosis for most such patients with appropriate management is excellent, with mortality under 10% even in those 40% of patients found to have cervical node metastases. Risk factors affecting life expectancy include tumor type, size of primary tumor, tumor capsular and vascular invasion, distant (non-cervical) metastases and age at diagnosis. In the presence of significant risk factors, an aggressive approach is indicated in selected patients, starting with near total or total thyroidectomy. Radioiodine is the major adjunctive agent and its use must be individualized, but experience has established that optimum prognosis and effectiveness of therapy is enhanced by recognition of the basic principles of this type of radiation therapy. Issues and techniques in radioiodine management of post-surgical thyroid cancer will be discussed.