Iodine-131(131I) treatment for recurrent and metastatic thyroid cancer has been performed for over 50 years. In Japan, total thyroidectomy followed by 131I therapy is indicated in selected patients with distant metastases or at a high risk of local recurrence, and 131I is not used routinely for thyroid remnant ablation. 131I is concentrated in 60-70 % of metastases. Radioiodine uptake in metastatic lesions is more in younger patients than that in older patients. Hypothyroidism is often mild or
... ven absent in patients with large amount of tumor tissues, indicating that thyroid hormones produced by highly differentiated tumors compensate partially or even completely for hypothyroidism following total thyroidectomy. Adequate uptake of 131I is associated with reduction in the size and the number of metastases. However, our patients with positive 131I scan results did not show a decreased mortality rate as compared with those without 131I uptake. We assume that the scan positive group included more patients with advanced disease. We found adequate uptake was significantly associated with more favorable prognosis in patients with lung metastases alone and in those with a similar range of serum thyroglobulin concentrations. Old patients with extensive metastases and/or bulky tumor masses in the bone have a poor prognosis irrespectively of the scan results. Thus, favorable factors for longer prognosis are younger age, adequate uptake of 131I in metastases, small extent of the disease and early discovery of metastases. Consequently, it is important to discover metastases as early as possible when patients are young. Long-term periodical thyroglobulin determination and imaging studies are strongly recommended. 76 12th International Thyroid Congress FOLLOW-UP STUDIES OF PAPILLARY CANCER OF THE THYROID. Aim: To look for the changes of papillary cancer of the thyroid in the last 5 decades in clinical features and results of treatment. Patients and Methods: Of 6756 patients with thyroid malignancies seen in our institution, 5126 had papillary cancer. The following patients were excluded: patients who were not treated with curative intent, and whose primary tumor was less than 10 mm in maximum diameter. Remaining 3698 were studied. The patients were divided into 3 groups based on the period of initial surgery. Patients operated on before 1970 (early group), between 1970 and 1983 (middle group), and between 1984 and 1996 (recent group). Results: The types of thyroidectomy became more extensive with time. Modified radical neck dissection was most frequently performed in middle group. Median diameter of the primary tumor decreased with time and median age at operation increased. Cause specific 10-year survival rates were improved with time. Risk factors calculated with Cox's model revealed that in early group sex, age, diameter of the primary tumor, extrathyroidal invasion and presence of gross nodal metastasis were risk factors. In the middle group risk factors were age, diameter and gross nodal metastasis. In the recent group, only age and gross nodal metastasis were risk factors. Conclusion: Age is one of the most important risk factors of papillary cancer as well as the size of the primary tumor. Patients in recent group were in average older than that of other groups; however, their 10-year survival rate was favorable than the other groups. This may be explained by the fact that the recent group was consisted with patients with smaller tumor, and favorable effect of the size overwhelmed the harmful effect of age.