Effect of radioiodine therapy on pulmonary metastases from well-differentiated thyroid cancer

Objective: To investigate effect of radioiodine therapy on pulmonary metastases from well-differentiated thyroid cancer. Methods: Fifty-eight cases of pulmonary metastases were studied utilizing chest X-ray, pulmonary function test and 99Tcm-DTPA aerosol clearance examination. Results: The data of pulmonary function test were of no difference between groups of various radiation doses cumulation (P > 0.05). The differences of vital capacity (VC), fast vital capacity (FVC) and forced expiratory volume in one second (FEV1) were not remarkable between the two groups of male or female patients (P > 0.05), but the difference of maximal volume ventilation (MVV) was P < 0.01. 99Tcm-DTPA aerosol clearance rates between various groups were of no difference (P > 0.05). Only for one female, 43 years old who had received an accumulative dose of 51.8 GBq radioiodine over an 8-yr period, her pulmonary function test showed evidence of restrictive lung disease, chest X-ray showed haziness and DTPA half-time clearance was 26.4 min, which is suggestive of interstitial fibrosis. Conclusion: The cumulative dose of radioiodine and gender of the patients had not statistically significant effects on the pulmonary function. Interstitial fibrosis must be carefully watched when the cumulative radioiodine dose is over 37 GBq