Morphological Changes Induced by Bipolar Radiofrequency Ablation in Thyroid Nodules - a Preclinical Ex Vivo Investigation.

Introduction: Recently, radiofrequency ablation (RFA) has been increasingly used for the treatment of thyroid nodules. However, immediate morphological changes associated with bipolar devices are poorly shown. Aims: To present the results of analysis of gross and microscopic alterations in human thyroid tissue induced by RFA delivered through the application of the original patented device. Materials and methods: In total, there were 37 surgically removed thyroid glands in females aged 32-67 at presentation: 16 nodules were follicular adenoma (labelled as 'parenchymal' solid benign nodules) and adenomatous colloid goitre was represented by 21 cases. The thyroid gland was routinely processed and the nodules were sliced into two parts - one was a subject for histological routine processing according to the principles that universally apply in surgical pathology, the other one was used for the RFA procedure. Results: No significant difference in size reduction between parenchymal and colloid nodules was revealed (p>0.1, t-test) straight after the treatment. In addition, RFA equally effectively induced necrosis in follicular adenoma and adenomatous colloid goitre (p>0.1, analysis of variance test). As expected, tumour size correlated with size reduction (the smaller the size of the nodule, the greater percentage of the nodule volume that was ablated): r=-0.48 (p<0.0001). Conclusion: The results make it possible to move from ex vivo experiments to clinical practice.

Introduction and use of video-assisted endoscopic thyroidectomy for patients in Belarus affected by the Chernobyl nuclear disaster.

INTRODUCTION: We developed video-assisted neck surgery (VANS) - a feasible, simple, and safe endoscopic thyroid procedure with cosmetic benefits - in 1998. To date, we have performed this procedure 633 times. We have also introduced the VANS method in Belarus, a country that was left contaminated by the Chernobyl nuclear disaster. METHODS: From a mass screening, nine Belarusian patients, including two with papillary carcinoma of the thyroid, were selected to undergo an operation using the VANS method, performed by a single surgeon (author Shimizu). We compared indicating factors for minimally invasive surgery, specifically the operating time and blood loss, between the Belarusian cases and the 33 most recent cases performed at our institute in Tokyo. RESULTS: The procedures in Belarus were performed under very different working conditions than in Japan. However, operating time and blood loss improved for the Belarusian cases as the surgeon gained experience in this environment; all the cosmetic outcomes were excellent. Subsequently, over a 2-year period, surgeons in Belarus performed the VANS method, with modification, for 29 cases of thyroid tumor. CONCLUSION: The VANS method is easily learned by inexperienced surgeons without major technical problems.

The FOXE1 locus is a major genetic determinant for radiation-related thyroid carcinoma in Chernobyl.

Papillary thyroid cancer (PTC) among individuals exposed to radioactive iodine in their childhood or adolescence is a major internationally recognized health consequence of the Chernobyl accident. To identify genetic determinants affecting individual susceptibility to radiation-related PTC, we conducted a genome-wide association study employing Belarusian patients with PTC aged 0-18 years at the time of accident and age-matched Belarusian control subjects. Two series of genome scans were performed using independent sample sets, and association with radiation-related PTC was evaluated. Meta-analysis by the Mantel-Haenszel method combining the two studies identified four SNPs at chromosome 9q22.33 showing significant associations with the disease (Mantel-Haenszel P: mhp = 1.7 x 10(-9) to 4.9 x 10(-9)). The association was further reinforced by a validation analysis using one of these SNP markers, rs965513, with a new set of samples (overall mhp = 4.8 x 10(-12), OR = 1.65, 95% CI: 1.43-1.91). Rs965513 is located 57-kb upstream to FOXE1, a thyroid-specific transcription factor with pivotal roles in thyroid morphogenesis and was recently reported as the strongest genetic risk marker of sporadic PTC in European populations. Of interest, no association was obtained between radiation-related PTC and rs944289 (mhp = 0.17) at 14p13.3 which showed the second strongest association with sporadic PTC in Europeans. These results show that the complex pathway underlying the pathogenesis may be partly shared by the two etiological forms of PTC, but their genetic components do not completely overlap each other, suggesting the presence of other unknown etiology-specific genetic determinants in radiation-related PTC.