Yuchen Jin1, Maomei Ruan1,2, Lingxiao Cheng1,3, Hao Fu1, Min Liu1, Shiwei Sheng1, Libo Chen1. 1. 1 Department of Nuclear Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, P.R. China. 2. 2 Department of Nuclear Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, P.R. China. 3. 3 Department of Nuclear Medicine, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Zhejiang, P.R. China.
Abstract
BACKGROUND:Radioiodine (131I) remnant ablation (RRA) has become a key step in the postoperative treatment of differentiated thyroid cancer (DTC). However, inadequate or excessive 131I is common using fixed activities. This study was designed to explore the feasibility of radioiodine uptake and thyroglobulin (RAIU-Tg)-guided RRA. METHODS:A total of 277 patients were randomized to the RAIU-Tg-based activity group or a fixed activity of 3.7 GBq group at a ratio of 4:1. The RAIU-Tg-based activity was established based on four levels of RAIU (≤2%, 2-5%, 5-15%, and >15%) and Tg levels (≤2, 2-5, 5-10, and >10 ng/mL). Based on this, 131I activities of 1.1, 1.85, 3.7, and 5.55 GBq were administered. If the levels for RAIU and Tg were not in the same category, the higher activity determined by either RAIU or Tg was administered. Successful RRA was defined as negative diagnostic whole-body scan and Tg <1 ng/mL (anti-Tg antibody negative) or negative diagnostic whole-body scan (anti-Tg antibody positive) under thyrotropin stimulation six months or more post RRA. RESULTS: There was no statistically significant difference in baseline characteristics between the RAIU-Tg-based activity group (n = 207) and the fixed activity group (n = 58). The activity of 131I used in the RAIU-Tg-based activity group (3.26 ± 1.54 GBq) was significantly lower than that used in the fixed activity group (p < 0.0001), whereas the rate of successful RRA in the RAIU-Tg-based activity group was significantly higher than the rate in the fixed activity group (94.2% vs. 70.7%; p < 0.0001). The rates of successful RRA in the four subgroups of the RAIU-Tg-based activity group were comparable (p = 0.543). Although there was no statistically significant difference in the incidence of total/short-term adverse effects between the RAIU-Tg-based activity group and the fixed activity group, a significantly lower incidence of intermediate adverse effects, which predominantly consisted of xerostomia, was reported in the RAIU-Tg-based activity group. CONCLUSIONS: Compared to a fixed activity of 3.7 GBq, RAIU-Tg-guided dosimetry can improve the success rate and decrease the incidence of intermediate side effects of RRA in postoperative patients with DTC.
RCT Entities:
BACKGROUND:Radioiodine (131I) remnant ablation (RRA) has become a key step in the postoperative treatment of differentiated thyroid cancer (DTC). However, inadequate or excessive 131I is common using fixed activities. This study was designed to explore the feasibility of radioiodine uptake and thyroglobulin (RAIU-Tg)-guided RRA. METHODS: A total of 277 patients were randomized to the RAIU-Tg-based activity group or a fixed activity of 3.7 GBq group at a ratio of 4:1. The RAIU-Tg-based activity was established based on four levels of RAIU (≤2%, 2-5%, 5-15%, and >15%) and Tg levels (≤2, 2-5, 5-10, and >10 ng/mL). Based on this, 131I activities of 1.1, 1.85, 3.7, and 5.55 GBq were administered. If the levels for RAIU and Tg were not in the same category, the higher activity determined by either RAIU or Tg was administered. Successful RRA was defined as negative diagnostic whole-body scan and Tg <1 ng/mL (anti-Tg antibody negative) or negative diagnostic whole-body scan (anti-Tg antibody positive) under thyrotropin stimulation six months or more post RRA. RESULTS: There was no statistically significant difference in baseline characteristics between the RAIU-Tg-based activity group (n = 207) and the fixed activity group (n = 58). The activity of 131I used in the RAIU-Tg-based activity group (3.26 ± 1.54 GBq) was significantly lower than that used in the fixed activity group (p < 0.0001), whereas the rate of successful RRA in the RAIU-Tg-based activity group was significantly higher than the rate in the fixed activity group (94.2% vs. 70.7%; p < 0.0001). The rates of successful RRA in the four subgroups of the RAIU-Tg-based activity group were comparable (p = 0.543). Although there was no statistically significant difference in the incidence of total/short-term adverse effects between the RAIU-Tg-based activity group and the fixed activity group, a significantly lower incidence of intermediate adverse effects, which predominantly consisted of xerostomia, was reported in the RAIU-Tg-based activity group. CONCLUSIONS: Compared to a fixed activity of 3.7 GBq, RAIU-Tg-guided dosimetry can improve the success rate and decrease the incidence of intermediate side effects of RRA in postoperative patients with DTC.