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

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 (131)I therapy. This retrospective study aimed to investigate the therapeutic effect and analyze the influence factors on (131)I treatment of DTC with lymph node metastases.

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 (131)I therapy, when the metastases were found, the history of resection of the lymph node metastases, the uptake of (18)F-FDG in the lymph node metastases, remnant thyroid, multiple metastases, and the cumulative dose of (131)I. This retrospective study was analyzed by Student t test, chi(2) test, and Fisher's exact test.

Of all 66 patients with lymph node metastatic DTC treated by (131)I 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 (chi(2)=5.561, P=.018<0.05). The elimination rate of lymph node metastases in patients with (18)F-FDG uptake was significantly higher than in those without (18)F-FDG uptake (chi(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.

(131)I Therapy is an effective treatment of lymph node metastatic DTC. The history of resection of the lymph node metastases and the uptake of (18)F-FDG in the lymph node metastases were the influence factors on the therapeutic effect, whereas the other eight factors were probably not.