Atsuhiro Nakatsuka

Percutaneous Radiofrequency Ablation of Lung Neoplasms: Initial Therapeutic Response

PURPOSE To evaluate the feasibility, safety, and initial therapeutic effect of radiofrequency (RF) ablation in the treatment of unresectable malignant lung tumors. MATERIALS AND METHODS Fifty-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). RESULTS RF 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. CONCLUSION Lung 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.

Transcatheter arterial embolization of ruptured pseudoaneurysms with coils and n-butyl cyanoacrylate.

PURPOSE To evaluate the clinical efficacy of transcatheter arterial embolization with n-butyl cyanoacrylate (NBCA) for ruptured pseudoaneurysms, which are difficult to control by coil embolization alone. MATERIALS AND METHODS Ruptured pseudoaneurysms developed at the celiac trunk (n = 1), gastroduodenal artery (n = 2), pancreatic arcade (n = 1), hepatic artery (n = 3), renal artery (n = 1), and intercostal artery (n = 1) in nine patients. NBCA was mixed with iodized-oil (1:2) and injected via the 3-F microcatheter under fluoroscopic guidance, after the catheter was advanced close to the pseudoaneurysm. Coil embolization was performed to control blood flow before administration of NBCA in seven patients. NBCA was injected immediately after coil embolization in four patients. Embolization with NBCA was performed for recurrent bleeding that occurred within 1-21 days (mean, 10.7 days) after initial coil embolization in three patients. Two patients with peripheral pseudoaneurysms underwent embolization with NBCA alone. RESULTS The NBCA mixture was visible under fluoroscopy, and was useful in monitoring the embolization process and deciding the endpoint. Embolization was technically successful without major complications in all patients. Pseudoaneurysms and afferent and efferent arteries were eliminated immediately after embolization. Bleeding was stopped after embolization in all cases. Rebleeding did not occur in any patient during their follow-up periods of 0.7-69.5 months (mean, 17.9 months). CONCLUSION Embolization with NBCA is a feasible and useful treatment for ruptured pseudoaneurysms, which are difficult to control by coil embolization alone.

Radiofrequency ablation combined with chemoembolization in hepatocellular carcinoma: treatment response based on tumor size and morphology.

PURPOSE To evaluate local therapeutic efficacy of radiofrequency (RF) ablation after chemoembolization for hepatocellular carcinoma (HCC) based on tumor size and morphology. MATERIALS AND METHODS Sixty-four patients underwent RF ablation under ultrasonographic or real-time computed tomographic (CT) fluoroscopic guidance within 2 weeks after chemoembolization. One hundred eight lesions were treated. Sixty-five lesions were small (<or=3 cm), 32 were intermediate in size (3.1-5 cm), and 11 were large (5.1-12 cm). Seventy-four of the HCCs were nodular lesions and the other 34 were nonnodular (multinodular and infiltrative) lesions. Response to treatment was evaluated by dynamic enhanced CT and magnetic resonance imaging. Tumor necrosis was considered to be complete when no foci of enhancement were seen within the tumor and at its periphery. RESULTS Complete necrosis was achieved in all lesions regardless of tumor size or morphology. There have been no local recurrences in small and intermediate-sized lesions regardless of tumor morphology during a mean follow-up of 12.5 months. In large HCCs, nodular lesions showed no recurrence, but two of six of nonnodular lesions recurred beyond the thermal lesions created around the tumor. The estimated 1-year survival rate was 98.0% in all patients. CONCLUSIONS This combined therapy has a therapeutic effect on small and intermediate-sized HCCs regardless of tumor morphology and is a promising treatment option for large nodular lesions. Control of large nonnodular lesions is still a challenging problem.

Early-stage hepatocellular carcinoma: radiofrequency ablation combined with chemoembolization versus hepatectomy.

PURPOSE To retrospectively evaluate the long-term results of radiofrequency (RF) ablation combined with chemoembolization (combination therapy) as compared with hepatectomy for the treatment of early-stage hepatocellular carcinoma (HCC). MATERIALS AND METHODS The study was approved by the institutional review board, and informed consent was waived. Patients with early-stage HCC were included if they underwent either combination therapy or hepatectomy and met the following inclusion criteria: no previous treatment for HCC, three or fewer tumors with a maximum diameter of 3 cm or less each or a single tumor with a maximum diameter of 5 cm or less, Child-Pugh class A liver profile, no vascular invasion, and no extrahepatic metastases. The primary endpoint was overall survival, and the secondary endpoint was recurrence-free survival. RESULTS One hundred four patients (mean age, 66.5 years +/- 8.7 [standard deviation]; 79 men, 25 women) underwent combination therapy, and 62 patients (mean age, 64.5 years +/- 9.6; 51 men, 11 women) underwent hepatectomy. The 1-, 3-, and 5-year overall survival rates following combination therapy (98%, 94%, and 75%, respectively) were similar (P = .87) to those following hepatectomy (97%, 93%, and 81%, respectively). The 1-, 3-, and 5-year recurrence-free survival rates were also comparable (P = .70) for combination therapy (92%, 64%, and 27%, respectively) and hepatectomy (89%, 69%, and 26%, respectively). CONCLUSION RF ablation combined with chemoembolization in patients with early-stage HCC provides overall and disease-free survival rates similar to those achieved by hepatectomy.

Radiofrequency Ablation Combined with Bone Cement Injection for the Treatment of Bone Malignancies

PURPOSE To evaluate the feasibility, safety, and effectiveness of combined treatment with radiofrequency (RF) ablation followed by bone cement injection in patients with malignant bone neoplasms. MATERIALS AND METHODS Seventeen patients with 23 bone tumors were treated. The tumors, measuring 1.2-15 cm (mean, 4.9 +/- 3.5 cm), were located in the spine (n = 17), iliac bone (n = 3), sacrum (n = 2), and ischial bone (n = 1). All procedures were performed with computed tomographic (CT) fluoroscopic guidance. An electrode with an internally cooled tip was placed in the bone tumor through a biopsy needle and RF energy was applied, followed by cement injection. Pain relief was evaluated with use of the visual analogue scale score (VAS score). Local therapeutic effects were evaluated by contrast-enhanced MR imaging. Lack of tumor enhancement was considered to indicate necrosis. RESULTS The procedures were technically successful in all patients except for one patient with an osteoblastic ischial lesion (22 of 23 patients; 96%). Pain was relieved within 1 week in all 13 patients who reported pain (13 of 13 patients; 100%), with a significant decrease in the VAS score from 8.4 to 1.1 (P <.001). Tumor necrosis was observed in 71% +/- 24% of the tumor volume (range, 14%-100%). Neural damage occurred in four patients in whom the tumor had invaded the posterior cortex of the vertebral body and pedicle. CONCLUSION The combined therapy described here is both feasible and useful for the treatment of malignant bone neoplasms. The safety of the procedure depends on the tumor location. When the tumor is adjacent to the spinal cord, there is a risk of nerve injury.

Complications After 1000 Lung Radiofrequency Ablation Sessions in 420 Patients: A Single Center’s Experiences

OBJECTIVE This study retrospectively evaluates complications after lung radiofrequency ablation (RFA). MATERIALS AND METHODS Complications were assessed for each RFA session in 420 consecutive patients with 1403 lung tumors who underwent 1000 RFA sessions with a cool-tip RFA system. A major complication was defined as a grade 3 or 4 adverse event. Risk factors affecting frequent major complications that occurred with an incidence of 1% or more were detected using multivariate analysis. RESULTS Four deaths (0.4% [4/1000]) related to RFA procedures occurred. Three patients died of interstitial pneumonia. The other patient died of hemothorax. The major complication rate was 9.8% (98/1000). Frequent major complications were aseptic pleuritis (2.3% [23/1000]), pneumonia (1.8% [18/1000]), lung abscess (1.6% [16/1000]), bleeding requiring blood transfusion (1.6% [16/1000]), pneumothorax requiring pleural sclerosis (1.6% [16/1000]), followed by bronchopleural fistula (0.4% [4/1000]), brachial nerve injury (0.3% [3/1000]), tumor seeding (0.1% [1/1000]), and diaphragm injury (0.1% [1/1000]). Puncture number (p < 0.02) and previous systemic chemotherapy (p < 0.05) were significant risk factors for aseptic pleuritis. Previous external beam radiotherapy (p < 0.001) and age (p < 0.02) were significant risk factors for pneumonia, as were emphysema (p < 0.02) for lung abscess, and serum platelet count (p < 0.002) and tumor size (p < 0.02) for bleeding. Emphysema (p < 0.02) was a significant risk factor for pneumothorax requiring pleural sclerosis. CONCLUSION Lung RFA is a relatively safe procedure, but it can be fatal. Risk factors found in this study will help to stratify high-risk patients.

Percutaneous radiofrequency ablation of liver neoplasms adjacent to the gastrointestinal tract after balloon catheter interposition.

A hepatocellular carcinoma compressing the duodenum and a metastatic liver tumor adherent to the stomach were treated by radiofrequency ablation after a balloon was percutaneously placed between the tumor and the gastrointestinal tract to avoid bowel perforation. Neither tumor showed enhancement on dynamic contrast material-enhanced CT after radiofrequency ablation. There were no complications related to the procedures.

Regeneration of the un-embolized liver parenchyma following portal vein embolization

BACKGROUND/AIMS Portal vein embolization (PVE) induces atrophy of the embolized hepatic parenchyma and hypertrophy of the un-embolized liver. It is important to predict hypertrophy of un-embolized liver following PVE to decide a subsequent tactics in patients with liver tumors. The hypertrophy following PVE was evaluated in reference to embolized liver volume and a preceding use of transcatheter hepatic arterial chemoembolization (HACE) in this study. METHODS Thirty patients with liver tumors were studied. PVE was performed transhepatically. Ethanol (15-65 ml) was injected into portal veins, which perfused the liver segment bearing the tumor until occlusion. Embolization was performed at subsegmental portal branches in five patients, segmental branches in 11 patients and right portal veins in 14 patients. Twenty-three patients with underlying chronic liver disease and hepatocellular carcinoma (HCC) underwent PVE 2-6 weeks after HACE. The remaining seven patients without underlying chronic liver disease had bile duct cancer (6) or liver metastasis (1), and underwent PVE alone. Segmental volume in the liver was measured with computed tomography before and 4 weeks after PVE. RESULTS The degree of hypertrophy showed a significant correlation with embolized liver volume (r=0.685, p<0.001). Increase in un-embolized liver volume was 2.4+/-5.8% with subsegmental embolization (NS), 15.2+/-6.4% with segmental embolization (p<0.01) and 46.5+/-18.8% with right PVE (p<0.001). In 14 patients with right PVE, degree of hypertrophy in seven patients with HACE was greater than that in seven patients without HACE (56.7+/-21.6% vs 36.4+/-7.4%; p<0.03). CONCLUSIONS Hypertrophy of the un-embolized liver parenchyma following PVE was correlated with embolized liver volume and was augmented with combined use of HACE.

Midterm results of radiofrequency ablation versus nephrectomy for T1a renal cell carcinoma.

PurposeThe aim of this study was to retrospectively evaluate midterm results of renal radiofrequency (RF) ablation compared to the results after nephrectomy in patients with T1a renal cell carcinoma (RCC).Materials and methodsA total of 115 patients with a single RCC measuring ≤4 cm (T1a) were included; 51 patients underwent RF ablation, 54 patients radical nephrectomy, and 10 patients partial nephrectomy. The survival and the percent decreases in glomerular filtration rate (GFR) were compared among the three treatments.ResultsAlthough overall survival after RF ablation (75.0% at 5 years) was lower than those after radical and partial nephrectomy, the RCC-related survival (100% at 5 years) was comparable to those following radical nephrectomy (100% at 5 years) and partial nephrectomy (100% at 3 years). The disease-free survival (DFS) after RF ablation (98.0% at 5 years) was also comparable to those after radical nephrectomy (95.0% at 5 years) (P = 0.72) and partial nephrectomy (75.0% at 3 years) (P = 0.13). The percent decrease in the GFR at last follow-up in the RF ablation group (median 7.9%) was significantly lower than that in the radical nephrectomy group (median 29.0%) (P < 0.001) and comparable to that in the partial nephrectomy group (median 11.5%) (P = 0.73).ConclusionRF ablation provides RCC-related and DFS comparable to that found after nephrectomy with little loss of renal function.

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

PURPOSE This study was undertaken to compare the thermal lesion volumes in normal pig lungs when radiofrequency (RF) ablation is performed with and without airway occlusion. MATERIALS AND METHODS RF 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. RESULTS Tissue 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). CONCLUSION Prevention 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.