Pulmonary function in thyroid carcinoma metastatic to the lung.

Pulmonary testing was carried out in 12 of 35 consecutive cases of differentiated thyroid carcinoma metastatic to the lung, which were identified in a retrospective analysis covering the 22-yr period from 1962-1984. In 7 of the 12 patients, pulmonary function tests showed abnormalities. Impaired pulmonary function was associated with a poor prognosis. Four of the twelve patients died; each had impaired pulmonary function and their ages (12-65 yr) were similar to those still living (13-65 yr). Specific types of functional abnormalities were not associated with pulmonary metastases, and underlying pulmonary disease contributed to the findings in some patients. Four patterns were defined on chest radiographs: macronodular, micronodular, miliary, and normal, but these patterns did not correlate with outcome. Scintiscan patterns varied from normal to diffuse concentration of 131I. Generally, following therapy with radioiodine, fewer abnormalities on chest x-ray and less uptake of 131I in the lungs was noted. However, therapy with radioiodine did not improve pulmonary function. Pulmonary function testing appears to be a better predictor of outcome in patients with thyroid carcinoma metastatic to lung than chest x-ray appearance or scintigraphic scanning.