Combination of ultrasound guided percutaneous microwave ablation and radioiodine therapy in benign thyroid diseases A suitable method to reduce the 1311 activity and hospitalization time?

Aim: Goiters and thyroid nodules are an ongoing problem in healthcare. There has not been any treatment of goiters and thyroid nodules based on the combined therapy of microwave ablation (MWA) and radioiodine therapy (RIT) until now. In this study the potential benefit of a combined therapy versus single RIT is evaluated in order to achieve improvements concerning I-131-dose and hospitalization time. Patients, material, methods: Ten patients with goiter and benign thyroid nodules or Graves' disease were included. Pre-ablation assessments included sonographical imaging, functional imaging with Tc-99m and FNAB to collect data of nodules and total thyroid volume and to exclude malignancy. Prior to treatment, radioiodine uptake test was performed. MWA was operated under local anesthesia with a system working in a wavelength field 902-928 MHz. Post-MWA, thyroid volume was recalculated ultrasonically. Due to reduced vital volume, changes of I-131-dose and hospitalization time could be monitored. Results: Mean absolute thyroid volume reduction by MWA before applying RIT was 22 +/- 11 ml, meaning a relative reduction of 24 +/- 6% (p < 0.05). Thereby, administered activity could be reduced by 393 +/- 188 MBq using the combined therapy, reflecting a relative reduction of 24 +/- 6% (p < 0.05). Additionally, mean hospitalization time was decreased by 2.1 +/- 0.8 days using MWA prior to RIT, implying a relative reduction of 28 +/- 6% (p < 0.05). Conclusion: Depending on ablated volume by MWA, RIT-monotherapy requires on average 31.2% more I-131-activity than the combined therapy. The combined therapy remarkably decreases I-131-dose and hospitalization time. The combined MWA and RIT therapy is a considerable, effective and safer alternative to surgery for the treatment of very large benign nodular goiters.