Pulmonary metastases in differentiated thyroid carcinoma. Study of 58 cases with implications for the primary tumor treatment.

Fifty-eight cases of pulmonary metastases (PM) from 831 cases of differentiated thyroid carcinoma (DTC) were studied. PM were found in about 10% of follicular and 5% of papillary tumors. 131I uptake was found in 55% of the cases, irrespective of histology. Twenty-one patients were treated by 131I only and 12 were cured. Micronodular metastases, 92% papillary, with 86% positive 131I uptake and 77% 8-year survival rate, are the most favorable forms. In others the influence of PM size/age, uptake, delay of appearance, presence of cervical or mediastinal lymph nodes is discussed. Occurrence of late PM according to treatment of the primary tumor was 1.3% thyroidectomy + 131I; 3% thyroidectomy; 5% partial thyroidectomy + 131I; 11% partial thyroidectomy only. Thus prevention in DTC of severe PM (28% 8-year survival rate) can best be achieved by complete thyroidectomy + 131I ablation dose.