Clinical value of ¹²⁵I seeds implantation in treatment of lymph nodes metastases from ¹³¹I refractory differentiated thyroid carcinoma

Objective: To evaluate the clinical value of ¹²⁵I seeds implantation (RSI) for treatment of lymph nodes metastases (LNM) in patients with ¹³¹I refractory differentiated thyroid carcinoma (RAIR-DTC). Methods: A total of 42 RAIR-DTC patients with LNM (14 males, 28 females, median age 49 years) who underwent RSI guided by CT from January 2015 to June 2016 were retrospectively analyzed. All patients underwent CT and their serum thyroglobulin (Tg) levels were measured 2, 4 and 6 months post-treatment. The LNM size and serum Tg levels before and after treatment were compared, and the curative effect of RSI for complications was observed. Paired t test, χ² test, repeated measurement analysis of variance, Spearman correlation analysis were used to analyze the data. Results: Two patients (4.76%) achieved complete remission, 9 (21.43%) achieved partial remission, 29 (69.05%) had no change, 2 (4.76%) were with progressive disease in all 42 patients. The total effective rate was 95.24% (40/42). The LNM diameter post-treatment was (1.39 ± 0.75) cm, significantly lower than that before treatment ((1.99 ± 0.38) cm; t = 5.557, P < 0.01). The Tg level 2, 4 and 6 months posttreatment was (53.24 ± 14.05), (33.17 ± 7.61) and (25.93 ± 10.91) μg/L, respectively, which was significantly lower than that before treatment ((57.72 ± 15.23) μg/L; F = 23.612, all P < 0.05). The age, sex, metastatic site, and the number of seeds implanted in each lesion were not the influencing factors on RSI (χ² values: 0.569-15.884, rs = 0.277, all P > 0.05). The LNM size was the influencing factor on RSI (χ² = 4.524, P < 0.05). Conclusions: ¹²⁵I RSI can significantly alleviate the clinical symptoms of RAIR-DTC patients with LNM, and the LNM size has relevance for the treatment effect. The clinical follow-up time of serum Tg level can be extended to 6 months or even longer. (authors)