Journal of Cancer Research and Therapeutics Medknow Publications on behalf of the Association of Radiation Oncologists of India (AROI) ISSN: 0973-1482 EISSN: 1998-4138 Vol. 6, Num. 3, 2010, pp. 310-312

Journal of Cancer Research and Therapeutics, Vol. 6, No. 3, July-September, 2010, pp. 310-312

Case Report

Primary papillary thyroid carcinoma previously treated incompletely with radiofrequency ablation

Hoon Yub Kim, Woo Sang Ryu, Sang Uk Woo, Gil Soo Son, Eun Sook Lee, Jae Bok Lee, Jeoung Won Bae

Department of Surgery, Korea University College of Medicine, Seoul, Korea

Correspondence Address:Jeoung Won Bae, Department of Surgery, Korea University College of Medicine, Anam-Dong 5-Ga, Seongbuk-Gu, 136-705, Seoul, Korea, endocrsurg@gmail.com

Code Number: cr10070

PMID: 21119260

DOI: 10.4103/0973-1482.73328

Abstract

Keywords: Papillary thyroid carcinoma, radiofrequency ablation, robotic thyroid surgery

Introduction

Radiofrequency ablation (RFA) is a method of localized hyperthermia resulting in tissue necrosis, which has been increasingly used to treat hepatocellular carcinomas and metastatic liver tumors over the last 10 years, and recent reports have surfaced of the application of RFA to various other sites, including the prostate, kidney, breast, spleen, tongue, and thyroid gland. ^[1] In the thyroid, RFA has been applied to limited cases of local recurrences or focal distant metastases of well-differentiated thyroid cancer in the high-risk reoperative condition or for the palliative purpose, ^[2],[3] and recently to benign nodules mainly for cosmetic reasons. ^[4],[5] But neither the result of prospective trial nor the long-term follow-up data on the effectiveness of RFA treatment for the thyroid lesions is available, and furthermore no report has been made on the RFA for primary thyroid cancer. We report on a patient with primary papillary carcinoma of thyroid gland who had undergone RFA before the cytological diagnosis of malignancy, later referred and treated with robotic surgery successfully.

Case Report

A 44-year-old female patient was referred from the outside private hospital for the treatment of the malignant thyroid nodule, suspicious of papillary carcinoma, diagnosed by the fine fine-needle aspiration cytological examination (FNAC). She had undergone RFA of the nodule, just after the FNAC at the same time, that is, without confirmation of the diagnosis. It was reported that the RFA had been carried out for the 1.2- cm-sized nodule in the right lobe with 20-30 W of power for about 5 minutes under the ultrasonographic (US) guidance, using an internally cooled electrode (17 gauge, with 1-cm active chip) and an RF generator (Cool-tip RF system, Radionics, Valleylab, CO). On the preoperative US, a 1.6-cm-sized, taller than wide, hypoechoic nodule with multiple echogenic spots, suggesting microcalcifications, was detected in the mid mid-lateral aspect of right lobe of thyroid [Figure - 1]. Neither other thyroid lesion nor lymphadenopathy suggesting metastasis was observed on the US and computed tomography.

The patient underwent robotic total thyroidectomy and central node dissection using the bilateral axillo-breast approach, with the da Vinci^; surgical system (Intuitive Surgical, Sunnyville, CA, USA), exactly a month after the RFA. There was no specific intraoperative finding, except the mild adhesion of sternothyroid muscle with the antero-lateral surface of the mid to lower right lobe, which turned out to be the RFA portion [Figure - 2]. The total operative time was 305 minutes, and the console time was 117 minutes. More time was needed for the right lobectomy than for the left lobectomy (73 vs 41 minutes) due to the adhesion. No postoperative complication was observed, and the patient was discharged on the fourth postoperative fourth day. Pathological examination revealed a 0.7 cm× 7-cm-sized viable papillary carcinoma without extrathyroidal extension in the right lobe, back to back with 0.8-cm-sized ablated necrotic tissue [Figure - 3]. Metastases were detected in two out of six retrieved central lymph nodes. On the postoperative 1 month follow-up, the patient expressed satisfaction with her postoperative cosmetic results. Radioactive iodine therapy is planned.

Discussion

Patients with recurrent cervical well-differentiated thyroid cancer represent a difficult problem because of the significant risks associated with scars and adhesions from previous operations. Because this group of patients has undergone total thyroidectomy, neck dissection and radioactive iodine therapy, the anatomical planes are distorted and small lymph node recurrences can be very difficult to find even with the US guidance. Such surgical re-exploration of the neck can be associated with a high rate of morbidity, making US-guided RFA therapies an attractive treatment option for the limited number of patients who are at great risk of developing morbidity during the reoperation.

Recently RFA has been applied to benign thyroid nodules because it can reduce the volume of the nodules by inducing focal coagulative necrosis. Kim et al. ^[4] reported their initial experience of RFA for benign thyroid nodules, and showed that the residual volume after thyroid RFA was approximately 11.8% at the 9- to 18.5-month follow-up. Jeong et al. ^[5] reported that volume reduction ratio after the RFA greater than 50% was observed in 91.06% of nodules, and 27.81% of index nodules were disappeared at the 1- to 41-month follow-up.

Nowadays, RFA therapies for this cosmetic purpose are widely performed in local outpatient clinics in Korea. The Korea Thyroid Association recommends doctors to confirm the diagnosis of benign at least twice by FNAC before performing the RFA for thyroid nodules.

But in this case, RFA was mal-performed with the FNAC at the same time, in other words, without confirmation of the diagnosis. But fortunately histological examination revealed papillary carcinoma later, and the patient could undergo radical thyroid surgery using the da Vinci^; surgical system with acceptable cosmetic results.

To our knowledge, this is the first report showing the direct RFA effect on the primary thyroid carcinoma histologically. As described in the case report, RFA was incomplete for the primary cancer. Moreover, lymph-node metastases, which could not be detected by current preoperative imaging modalities, were present.

So in conclusion, RFA for the operable primary thyroid malignancy should be avoided, because of the possibility of the remnant viable cancer portion and the undetectable nodal metastasis. In addition, robotic or endoscopic thyroid surgery may be a feasible operative method for benign or malignant thyroid nodules previously treated with RFA.

References

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