^131I imaging and Tg levels： values of 1311 therapy in patients with lung metastases from differentiated thyroid carcinoma

Abstract

Objective To explore the value of ^131I imaging and serum Tg levels for assessment and monitoring of 131I therapy in patients with lung metastases from DTC. Methods From 2007 to 2011, 50 patients with DTC lung metastases were investigated. Diagnostic 131I imaging, Tg levels and 131I imaging ＋ Tg levels were used to monitor and assess the outcomes of 131I treatment, respectively. The effective rates between patient lesions with diffuse configuration and focus configuration in PET/CT images, patients with and without extra lung metastases, and among patients with different Tg levels （ 〈 100 μg/L, 100 - 10130 μg/L, 〉 1000 μg/L） were compared. Statistical analyses by X2 test, Fisher exact test and Wilcoxon rank sum test were performed using SPSS 11.5. Results Forty-eight DTC patients with pulmonary metastases were ob- served by positive findings based on 131I imaging. Eleven cases were negative and 24 cases got better after J31I treatment. The effective rate was 73% （35/48）. No difference was found between diffuse configuration or focus configuration （69% （ 11/16 ） vs 75 % （24/32）, X2 = 0. 211, P 〉 0.05 ）. Patients without extra lung metastases had better prognosis than those with extra lung metastases （70% （28/40） vs 3/10, X2 = 3. 868, P 〈 0. 05）. The Tg levels decreased to 78.3μg/L from 108.7 μg/L after 1311 treatment （Z = - 0. 698, P 〉 0. 05）. Tg levels decreased in 66% （33/50） patients and increased in 17 cases. Patients with Tg levels 〈100 μg/L had better efficiency than those with Tg levels 〉 1000 μg/L （80% （20/25） vs 3/10, P = 0. 015）. However, the effective rate was 67% （10/15） in the 100 - 1000 μg/L group, which was not sig- nificantly different from those in the other 2 groups （X2 = 0. 320, P 〉 0.05 ; P = 0.111 ）. Considering the combined results of 131I imaging and Tg levels determination, the effective ratio was 62% （31/50） with 6 clinically cured patients and 25 partially responsive patients. Conclusions 1311 imaging and Tg level analy- sis are both important procedures for lung metastases of DTC patients. A significant increase of Tg levels and extra distant lung metastases imply poor prognosis. Key words: Thyroid neoplasms ; Neoplasm metastasis ; Lung; Radionuclide imaging; Iodine radioisotopes ; Thyroglobulin