Koichiro Yamakado

Percutaneous Radiofrequency Ablation of Lung Neoplasms: Initial Therapeutic Response

PURPOSEnTo evaluate the feasibility, safety, and initial therapeutic effect of radiofrequency (RF) ablation in the treatment of unresectable malignant lung tumors.nnnMATERIALS AND METHODSnFifty-four lung neoplasms in 31 patients were treated with RF ablation. Thirteen tumors were primary lung cancers and 41 were pulmonary metastases. Tumor sizes ranged from 0.7 to 6.0 cm, with a mean size of 2.7 +/- 1.3 cm. After the RF electrode was placed in the tumor with computed tomographic (CT) fluoroscopic guidance, RF energy was applied. Initial therapeutic response was evaluated by (18) F fluorodeoxyglucose positron emission tomography (FDG-PET) and contrast-enhanced CT. The disappearance of FDG uptake on PET images and tumor enhancement on CT images were considered to indicate complete tumor necrosis. Complete necrosis rates were evaluated according to tumor size and type (primary or secondary lung neoplasm).nnnRESULTSnRF ablation was technically successful in all lesions. Complete necrosis was achieved in 32 of the 54 tumors (59%) after initial RF session. There was a significant difference in the rate of complete tumor necrosis between tumors 3 cm or less and tumors larger than 3 cm (69% vs. 39%; P <.05). Tumor type did not influence complete necrosis rates. Lung abscesses developed in two patients with large tumors.nnnCONCLUSIONnLung RF ablation is a feasible, relatively safe, and promising treatment for unresectable lung neoplasms. Tumor size is an important factor in achieving complete tumor necrosis.

Lung Radiofrequency Ablation with and without Bronchial Occlusion: Experimental Study in Porcine Lungs

PURPOSEnThis study was undertaken to compare the thermal lesion volumes in normal pig lungs when radiofrequency (RF) ablation is performed with and without airway occlusion.nnnMATERIALS AND METHODSnRF ablation was performed in six pigs. A straight 17-gauge internally cooled-tip electrode with a 2-cm exposed tip was inserted into the center of the lower lobe of the lung under biplane fluoroscopic guidance. In each animal, RF ablation was performed for 12 minutes with balloon occlusion of the main bronchus in one lung and without balloon occlusion in the contralateral lung. The tissue temperature around the electrode tip was measured immediately after RF application. The volumes of the thermal lesions were compared by histologic examination of the groups of lungs ablated with and without airway occlusion.nnnRESULTSnTissue temperature was significantly higher in the bronchial occlusion group than in the group with normal ventilation (51 degrees C +/- 7 vs. 44 degrees C +/- 2; P < .05). RF ablation with bronchial occlusion resulted in the creation of a significantly greater thermal lesion volume compared with RF ablation with normal ventilation (6,535 mm(3) +/- 1,114 vs 3,368 mm(3) +/- 676; P < .03).nnnCONCLUSIONnPrevention of ventilation in the normal swine lung via bronchial balloon occlusion during RF ablation increases the thermal ablation lesion volume, suggesting that active ventilation is a significant cause of in vivo heat loss.

Radiofrequency Ablation Combined with Renal Arterial Embolization for the Treatment of Unresectable Renal Cell Carcinoma Larger Than 3.5 cm: Initial Experience

The purpose of the study was to evaluate the feasibility, safety, and therapeutic effects of the combination of renal arterial embolization and radiofrequency (RF) ablation to reinforce the anticancer effect on renal cell carcinomas (RCCs) measuring 3.5 cm or larger. This study was undertaken to evaluate this combined therapy on large RCCs-based tumor geometry. Eleven patients with 12 RCCs 3.5 cm or larger in diameter (3.5–9.0 cm) underwent combined therapy. Two were exophytic tumors, and the remaining 10 tumors had components extending into the renal sinus fat. Tumor vessels were selectively embolized in nine patients and the renal artery was completely embolized in two patients with polyvinyl alcohol or ethanol mixed with iodized oil. RF ablation was percutaneously done under the computed tomographic (CT)–fluoroscopic guidance. Response to treatment was evaluated by dynamic contrast-enhanced CT and magnetic resonance (MR) imaging. Tumor enhancement was eliminated after a single RF session in nine tumors (75%), after two sessions in two tumors (17%), and after four sessions in one tumor (8%). Both exophytic tumors (100%) and 7 of 10 tumors having components in the renal sinus fat (70%) were completely ablated with a single RF session. All tumors remained controlled during a mean follow-up period of 13 months and showed significant reduction in tumor sizes (5.2 ± 1.7 cm to 3.6 ± 1.4 cm, p < 0.001). A delayed abscess developed in the ablated lesion in a patient, which was percutaneously drainaged. Combined therapy as described in this report is a feasible, relatively safe, and promising treatment method for large RCCs regardless of tumor geometry.

Prospective Study of Arterial Infusion Chemotherapy Followed by Radiofrequency Ablation for the Treatment of Liver Metastasis of Gastric Cancer

This prospective study was conducted to evaluate the efficacy of hepatic arterial infusion chemotherapy (HAIC) with use of an implanted port followed by radiofrequency (RF) ablation for the treatment of liver metastasis of gastric cancer. Seven patients without extrahepatic metastasis were enrolled. The maximum tumor size was less than 3 cm in one patient and 3.2-6.0 cm in the other six patients (mean, 4.4 cm +/- 1.5). Two patients had single lesions and the other five patients had two to six lesions each. The maximum tumor size was reduced to 3 cm or less (mean, 2.4 cm +/- 0.4; P < .03) after HAIC in all patients. The total number of tumors was reduced from 25 to 16. RF ablation was performed for all residual liver tumors, resulting in complete tumor necrosis. All but one patient are still living without intrahepatic recurrence, with a median survival time of 16.5 months.

Tumor Seeding Following Lung Radiofrequency Ablation: A Case Report

Lung radiofrequency (RF) ablation was performed for the treatment of a primary lung cancer measuring 2.5 cm in maximum diameter in a 78-year-old man. A contrast-enhanced computed tomography (CT) study performed 3 months after RF ablation showed incomplete ablation of the lung tumor and the appearance of a chest wall tumor 4.0 cm in maximum diameter that was considered to be the result of needle-tract seeding. RF ablation was performed for the treatment of both the lung and the chest wall tumors. Although tumor enhancement was eradicated in both of the treated tumors, follow-up CT studies revealed diffuse intra-pulmonary metastases in both lungs 2 months after the second RF session. He is currently receiving systemic chemotherapy.

Percutaneous Radiofrequency Ablation for the Treatment of Liver Neoplasms in the Caudate Lobe Left of the Vena Cava: Electrode Placement Through the Left Lobe of the Liver Under CT-Fluoroscopic Guidance

Five hepatocellular carcinomas and one liver metastasis located in the caudate lobe left of the inferior vena cava were successfully treated by radiofrequency (RF) ablation by placing the RF electrode into each tumor through the left lobe of the liver under the CT-fluoroscopic guidance. All tumors were free of enhancement on dynamic contrast-enhanced CT during the mean follow-up period of 6.3 months. There were no major complications related to the procedures.

Radiofrequency ablation for the treatment of hemorrhagic vaginal cancer.

Editor: Radiofrequency (RF) ablation has attracted a great deal of interest as a method for the treatment of various malignancies (1–3). In this report, we present a case of hemorrhagic vaginal cancer that was successfully treated by RF ablation. A 74-year-old woman visited our hospital with vaginal bleeding and severe anemia in April 2002. She had vaginal prolapse and a prominent hemorrhagic vaginal tumor with a maximum diameter of 15 cm. The vaginal tumor had invaded the urinary bladder and caused vesicovaginal fistula (Figure, part a). The vaginal tumor was proven by biopsy to be vaginal cancer of clinical stage IVA. The patient was judged to not be a candidate for surgical intervention because of her poor general condition. Although systemic chemotherapy and transarterial embolization of the internal iliac arteries were performed, the tumor became larger and tumor bleeding continued. Then, vaginal RF ablation was performed with epidural anesthesia five times during a 4-month period. The urinary bladder was continuously irrigated with cold saline solution via a three-channel urinary catheter to protect the bladder wall. A straight 17-gauge cooled-tip RF electrode (Radionics, Burlington, MA) was placed at three to six different sites during each RF session under computed tomographic fluoroscopic or ultrasound guidance. The first two RF procedures were performed in the supine position, but skin burns developed in the femoral region at the time of the second RF ablation session. The next three RF sessions were performed in the lithotomy position. To separate the vaginal tumor from the femoral skin, surgical gloves stuffed with gauze were placed between the tumor and the skin. Tumor bleeding ceased and the maximum tumor size was reduced from 15 cm to 4 cm after the fifth RF session (Figure, part b). The skin burns resolved with symptomatic treatment. The vesicovaginal fistula had become apparent as a result of shrinkage of the vaginal tumor, but the patient did not develop any complications such as uriDOI: 10.1097/01.RVI.0000188777.69563.AA