Radiofrequency Ablation to Treat Loco-Regional Recurrence of Well-Differentiated Thyroid Carcinoma

OBJECTIVE: To evaluate the efficacy of radiofrequency ablation (RFA) in the treatment of loco-regional, recurrent, and well-differentiated thyroid carcinoma. MATERIALS AND METHODS: Thirty-five recurrent well-differentiated thyroid carcinomas (RTC) in 32 patients were treated with RFA, between March 2008 and October 2011. RTCs were detected by regular follow-up ultrasound and confirmed by biopsy. All patients had fewer than 3 RTCs in the neck and were at high surgical risk or refused to undergo repeated surgery. Average number of RFA sessions were 1.3 (range 1-3). Post-RFA biopsy and ultrasound were performed. The mean follow-up period was 30 months. Pre- and post-RFA serum thyroglobulin values were evaluated. RESULTS: Thirty-one patients with 33 RTCs were treated with RFA only, whereas 1 patient with 2 RTCs was treated with RFA followed by surgery. At the last follow-up ultrasound, 31 (94%) of the 33 RTCs treated with RFA alone completely disappeared and the remaining 2 (6%) RTCs showed decreased volume. The largest diameter and volume of the 33 RTCs were markedly decreased by 93.2% (from 8.1 +/- 3.4 mm to 0.6 +/- 1.8 mm, p < 0.001) and 96.4% (from 173.9 +/- 198.7 mm3 to 6.2 +/- 27.9 mm3, p < 0.001), respectively. Twenty of the 21 RTCs evaluated with post-RFA biopsies (95%) were negative for malignancy. One (5%) showed remaining tumor that was removed surgically. The serum thyroglobulin was decreased in 19 of 26 patients (73%). Voice change developed immediately after RFA in 6 patients (19%) and was spontaneously recovered in 5 patients (83%). CONCLUSION: Radiofrequency ablation can be effective in treating loco-regional, recurrent, and well-differentiated thyroid carcinoma in patients at high surgical risk.

Effects of Extremely Low Frequency Elecromagnetic Fields on Thyroid Carcinogenesis Induced by N-bis(2-hydroxypropyl)nitrosamine and Sulfadimethoxine

PURPOSE: Long-term exposure to extremely low-frequency (60 Hz) electromagnetic fields (ELF-EMF) raises the questions of the induction of biological effects including tumorigenesis. One mechanism through which ELF-MFS could influence neoplastic development is the imbalance of cellular proliferation and cell apoptosis. The present study investigated the effect of ELF-EMF on chemically-induced thyroid carcinogenesis in a rat. METHODS: We examined cellular proliferation index measured by anti-Ki-67 antigen, apoptosis, apoptosis related proteins such as caspase 3 and p53, and cell cycle-related proteins (cyclin D1 and p21(WAF1/Cip1)). Forty Male F344 rats received a subcutaneous N-bis(2-hydroxypropyl)nitrosamine (DHPN, 2,800 mg/kg) injection, and 1 week later were allowed free access to drinking water containing sulfadimethoxine (0.1%) for 12 weeks. Twenty rats were exposed by ELF-EMF. During the carcinogenesis, sequential histological changes from hyperplasia, adenoma, and ultimately to overt carcinomas were noted. RESULTS: The exposure group of ELF-EMF, significantly increases the number size of carcinomas. Also, the proliferative and apoptotic indices were significantly increased in the ELF-EMF exposure group than in the control group. The caspase 3 protein expression did not show any significant changes between ELF-EMF group and control group. The p53 protein was not detected in both ELF-EMF exposure and control group. Among the cell cycle related proteins, cyclin D1, not p21(WAF1/Cip1), was significantly increased in adenomas and carcinomas in ELF-EMF exposure group compared with the control group. CONCLUSION: Exposure of ELF-EMF effects on chemically-induced rat thyroid carcinogenesis as results of altered increase of cellular proliferation, apoptosis, and cyclin D1 expression.