The study of influence factors on 131I treatment of differentiated thyroid carcinoma with lymph node metastases

Abstract

Objective Thyroid carcinoma is the most common malignant endocrine tumor, which comprises 1% in all human tumors. As for differentiated thyroid carcinoma (DTC), lymph nodes are the most common metastatic site for which the major treatment is 131I therapy. This retrospective study aimed to investigate the therapeutic effect and analyze the influence factors on 131I treatment of DTC with lymph node metastases. Methods Collecting clinical data of 66 DTC patients with lymph node metastases at the Department of Nuclear Medicine, Xin Hua Hospital from January 1996 to January 2006. Investigating the therapeutic effect firstly and then dividing 66 patients into an eliminated group and an uneliminated group according to the evaluation criteria of the therapeutic effect. Finally, observing the differences between the two groups. The significant differences in the following 10 influence factors were determined: gender, age, pathological type, the periods from the thyroidectomy to the first 131I therapy, when the metastases were found, the history of resection of the lymph node metastases, the uptake of 18F-FDG in the lymph node metastases, remnant thyroid, multiple metastases, and the cumulative dose of 131I. This retrospective study was analyzed by Student t test, χ 2 test, and Fisher's exact test. Results Of all 66 patients with lymph node metastatic DTC treated by 131I therapy, 31 patients (46.97%) had complete elimination. Twenty-seven patients were improved or controlled, and the overall effective rate reached 87.88%. The elimination rate of lymph node metastases in patients with resection was significantly higher than in those without resection ( χ 2=5.561, P=.018<0.05). The elimination rate of lymph node metastases in patients with 18F-FDG uptake was significantly higher than in those without 18F-FDG uptake ( χ 2=4.014, P=.045<.05). There was no significant difference in the elimination rate among the patients with various values in the other eight factors. Conclusions 131I Therapy is an effective treatment of lymph node metastatic DTC. The history of resection of the lymph node metastases and the uptake of 18F-FDG in the lymph node metastases were the influence factors on the therapeutic effect, whereas the other eight factors were probably not.