ECE2015 Eposter Presentations Thyroid cancer (90 abstracts)
In PTC, radioiodine required dose for thyroid remnant ablation is uncertain. Recent works show that low doses may be sufficient for low risk patients.
Aim: To evaluate the efficacy and safety of thyroid remnant ablation in patients with low-risk PTC by using 1100 MBq (30 mCi) outpatient doses.
Materials and methods: Twenty-five patients (24 women, 55 years-old mean age, range 3477) referred for ablation of postsurgical thyroid remnants diagnosed with low-risk PTC (pT1-T2, N0, M0) were studied. After total thyroidectomy, an outpatient ablation was performed with 1100 MBq of 131I under rhTSH stimulation with strict radiation protection measurements and dosimetry control at home environment. Whole body scan (WBS) and SPECT-CT were performed on the fifth day. Control of therapeutic efficacy was performed at 6 months, using WBS and SPECT-CT with 123I after stimulation with rhTSH. Basal and post-stimulated thyroglobulin levels were determined in both studies. Ablation was considered successful when no abnormal activity was observed in WBS and SPECT-CTs and when basal/stimulated thyroglobulin levels were under 1 and 2 ng/ml, respectively.
Results: All 25 patients showed thyroid uptake without uptaking adenopathies in the WBS and SPECT-CTs performed on the fifth day after administration of 131I. In 23/25 patients (92%) a successful ablation at 6-month efficacy control was achieved. One patient (5.1 ng/ml stimulated Tg) was re-treated with a new dose of 30 mCi and a second patient (2.3 ng/ml stimulated Tg) spontaneously normalised her basal and stimulated Tg levels at the 18-month control. Dosimetry on family members showed exposure levels of <0.2 mSv.
Conclusion: The postsurgical outpatient treatment with an activity of 1100 MBq is safe for the family environment and cost-effective in a great majority of patients with low-risk PTC.