Although the generally accepted therapies of toxic goitres are very effective in alleviating hyperthyroidism and/or thyroid ablation, there still remain some difficult cases that are not amenable to current therapeutic options. In 2002, Xiao et al.  proposed arterial embolization as a novel approach to thyroid ablative therapy. The authors performed selective arteriography, using Seldinger's technique , followed by embolization of thyroid arteries in 22 patients with Graves' disease. From that group, 14 patients remained euthyroid after SETA, 6 were operated on because of goitre and the other two needed a maintenance dose of antithyroid drug therapy . A similar study was performed by Zhao et al.  on 28 patients with Graves' disease. From that group of patients, 22 became euthyroid, five improved and one demonstrated temporary improvement, followed by recurrence of the disease. Both groups of investigators did not observe any serious complications in any of those patients and, after a follow-up period, ranging from 12 to 24 months, they considered the procedure to be effective, minimally invasive and safe [3, 4]. Interestingly enough, Zhao et al.  noted an increase of thyroid hormones together with a drop in TSH concentration on the third day after the embolization procedure. This is consistent with our observations in patients with differentiated thyroid cancer . Moreover, we observed a massive increase of thyroglobulin concentrations and a moderate increase of free thyroid hormones, together with a fall of TSH concentration after 48 hours from SETA. In our opinion, it resulted from ischemic necrosis of the thyroid gland. Although, SETA reduces thyroid blood supply, the veins are not closed, and blood outflow remains unconstrained. In consequence, colloid from dying thyrocytes (comprising Tg, T3, T4 and, probably, other biochemical compounds) gets into circulation. This creates a potential risk of thyrotoxicosis aggravation, which may be particularly important in elderly people with ischemic heart disease and/or serious arrhythmia. Moreover, the review of the literature did not help us elucidate any potential consequences of increased serum Tg concentration. However, in one earlier study, its authors described embolization of DTC metastases to have caused massive Tg increase, which – probably – resulted in adult respiratory distress syndrome . Considering the above observation, we suggested thyroidectomy to be performed till the 36th hour after preresective SETA, as till that time, we did not observe in our study any significant increase in concentrations of the parameters in question .
Tartaglia et al.  also observed the increased thyroid hormones concentrations after embolization of cervicomediastinal hyperfunctioning goitre, 7 days after SETA. The goal of preresective embolization in their case was thyroid volume reduction. The authors succeeded, observing shrinkage of the thyroid gland by half of its initial volume . A similar reduction of thyroid volume (from one third to one half of initial volume) was observed by Xiao et al. . Neither we, nor Ramos et al., observed any significant reduction of thyroid volume after SETA [7, 8]. However, as mentioned above, thyroidectomy was performed in the reported study up to the 36th hour after SETA, and up to the sixth day after SETA in our previous study and in the study and the study described by Ramos et al. . In the present group, the patient with retrosternal goitre was successfully operated through cervical incision after SETA. Comparing with retrospectively analysed patients, operated because of similar goitre, the patient was expected to require sternotomy. Although, after SETA, no important changes in thyroid volume were observed, we noted structural changes in the gland, which may have been responsible for the differences in its consistency, facilitating tumour removal. On the other hand, neither major nor even minor bleeding allowed performing radical manoeuvres, which could have accelerated the operation, and may have resulted in resection of the gland through cervical incision only.
The goal of SETA application in the present study was to decrease blood flow through a significant volume of thyroid tissue. Thus, decreased vascularization of thyroid tissue facilitated the removal of tumour, reducing blood loss and shortening the operation time. From the technical point of view, all the procedures were successful, effectively suppressing blood flow through the gland and resulting in a much smaller blood loss during thyroidectomy, decreased drainage and shortened operation time, although there was no difference in the rate of complications. On the other hand, the above mentioned differences were too small to justify routine applications of SETA as a pre-treatment method, even in cases of large toxic goitres. Preoperative SETA may potentially limit the risk of damaging the surrounding tissues, including the oesophagus, the parathyroid gland and recurrent laryngeal nerve. However, Tarttiglia et al.  reported, 30 days after SETA, a tight lesion and fibrous reaction and infiltration of giant multinucleate cells, probably caused by postembolization thyroiditis, that may have resulted in difficult recurrent laryngeal nerve preparation. Similar histological observations were described in the series by Xiao et al. .
The course of the treatment, applied to patient number ten, indicates potential values of SETA in quick preparation to surgery of patients with large toxic goitre and intolerance to anti-thyroid drugs (ATD) treatment. The patient was operated on in state of overt thyrotoxicosis. However, it should be underlined that the applied preresective SETA was followed by immediate thyroidectomy because of worsening respiratory insufficiency. Although the results of the treatment were excellent, the application of SETA as a pre-treatment to surgery in thyrotoxic patients with large goitres may only be recommended as the "last resort' treatment. On the other hand, recently Zhao et al.  published a case report of the patient with thyrotoxic crisis successfully cured with SETA. Unfortunately, considering the fact that similar patients are rarely seen in the day-to-day practice, no larger series of similar patients are likely to be investigated.