A systematic review of the effect of radioiodine-^131 in treatment of pulmonary metastases from differentiated thyroid carcinoma and the main prognostic factors

Objective To assess the effect of radioiodine-131 （^131 I ） on treatment of pulmonary metastases from differentiated thyroid carcinoma and the main prognostic factors. Methods Five databases were retrieved and all published studies which analyzed the effect of ^131I on pulmonary metastases from differentiated thyroid carcinoma and the main prognostic factors were systematically reviewed. The data about the impact of ^131I treatment and the main prognostic factors on the 5-yr and 10-yr survival rates of the patients were abstracted. RevMan 4.2 software was used to statistically analyze. Results Eleven retrospective cohort studies were included. The pooled results suggested that the 5-yr survival rates of the patients who received ^131 I therapy and who did not received ^131I therapy were 74.9% and 27.1% ,respectively;The 10-yr survival rates（ P〈0.01 ） of the two groups were 60.8% 和 12.2% , respectively;The difference between them had statistical significance （P〈0.01）. The 5-yr and 10-yr survival rates of the patients only with pulmonary metastases were higher than those of the patients with multiple metastases （ P〈0. 01 ）. The 5-yr （ P = 0. 01 ） and 10-yr （ P = 0. 002） surviv10al rates of the patients only with papillary thyroid carcinoma were higher than those of the patients with follicular thyroid carcinoma. The 5-yr and 10-yr survival rates of male and female patients were similar （ P 〉 0.05）. Conclusions ^131 I treatment increases the 5-yr and 10-yr survival rates of patients with pulmonary metastases from differentiated thyroid carcinoma. The extent of metastases and the histologic type of differentiated thyroid carcinoma are two main predicting factors of prognosis. The 5-yr and 10-yr survival rates of patients are not influenced by gender. Key words: Differentiated thyroid carcinoma;  Pulmonary metastases;  Radioiodine treatment;  Prognostic factor