Shinichi Hamamoto

Assessment of early treatment response after CT-guided radiofrequency ablation of unresectable lung tumours by diffusion-weighted MRI: a pilot study

The aim of this study was to evaluate prospectively the early treatment response after CT-guided radiofrequency ablation (RFA) of unresectable lung tumours by MRI including diffusion-weighted imaging (DWI). The study protocol was approved by the ethics committee of our hospital and signed consent was obtained from each patient. We studied 17 patients with 20 lung lesions (13 men and 4 women; mean age, 69+/-9.8 years; mean tumour size, 20.8+/-9.0 mm) who underwent RFA using a LeVeen electrode between November 2006 and January 2008. MRI was performed on a 1.5T unit before and 3 days after ablation. We compared changes in the apparent diffusion coefficient (ADC) on DWI and response evaluation based on subsequent follow-up CT. 14 of the 20 treatment sessions showed no local progression on follow-up CT, whereas 6 treatment sessions showed local progression (range, 3-17 months; mean, 6 months). For the no-progression group, the ADC pre- and post-RFA were 1.15+/-0.31 x 10(-3) mm(2) s(-1) and 1.49+/-0.24 x 10(-3) mm(2) s(-1), respectively, while the respective ADC values for those that showed local progression were 1.05+/-0.27 x 10(-3) mm(2) s(-1) and 1.24+/-0.20 x 10(-3) mm(2) s(-1). The ADC of the ablated lesion was significantly higher than before the procedure (p<0.05). There was a significant difference in the ADC post-RFA between no-progression and local progression groups (p<0.05). Our prospective pilot study showed that the ADC without local progression was significantly higher than with local progression after RFA, suggesting that the ADC can predict the response to RFA for lung tumours.

Radiofrequency Ablation and Immunostimulant OK-432: Combination Therapy Enhances Systemic Antitumor Immunity for Treatment of VX2 Lung Tumors in Rabbits

PURPOSE To evaluate whether antitumor immunity is enhanced systemically by combining radiofrequency ablation (RFA) and local injection of an immunostimulant, OK-432. MATERIALS AND METHODS Experiments were approved by the institutional animal care committee. Experimental Japanese rabbits inoculated with VX2 tumors in the lung and the auricle were randomized into four groups of eight: control (supportive care), RFA (RFA of lung tumor), OK-432 (direct injection of OK-432 into lung tumor), and combination therapy (lung RFA and direct OK-432 injection into lung tumor). All procedures were performed 1 week after implantation of VX2 tumors (week 1). In addition, a VX2 tumor rechallenge test was performed in the RFA and combination therapy groups. Survival time was evaluated by means of the Kaplan-Meier method and by using the log-rank test for intergroup comparison. Mean auricle tumor volumes were calculated every week. Specific growth rates (SGRs) were calculated and compared by using the Mann-Whitney test. RESULTS The median survival times of the control, RFA, OK-432, and combination therapy groups were 23, 36.5, 46.5, and 105 days, respectively. Survival was significantly prolonged in the combination therapy group when compared with the other three groups (P <.05). The mean auricle tumor volume decreased only in the combination therapy group. The mean auricle tumor volumes of the combination therapy group from week 1 to week 7 were 205, 339, 264, 227, 143, 127, and 115 mm(3). SGR in the combination therapy group became significantly smaller than those in the other three groups (P < .05). In the rechallenge test, the volume of all reimplanted tumors decreased. CONCLUSION Combining RFA with local injection of immunostimulant OK-432 may lead to indirectly activation of systemic antitumor immunity.

Percutaneous Computed Tomography–Guided Radiofrequency Ablation of Lung Tumors Complicated With Idiopathic Interstitial Pneumonia

We report 3 patients with lung cancer complicated with interstitial pneumonia who were treated by percutaneous computed tomography-guided radiofrequency ablation. Patient 1 recovered from a pneumothorax without chest drainage. Patient 2 presented with a progressive pneumothorax after discharge from the hospital and required readmission for air drainage. In patient 3, the pneumothorax did not improve by chest drainage and pleurodesis, and the patient died of acute exacerbation of interstitial pneumonia. Radiofrequency ablation of intractable lung cancer with complicating interstitial pneumonia requires careful consideration because a progressive pneumothorax may require surgical intervention or result in acute exacerbation of interstitial pneumonia.

Combination Radiofrequency Ablation and Local Injection of the Immunostimulant Bacillus Calmette–Guérin Induces Antitumor Immunity in the Lung and at a Distant VX2 Tumor in a Rabbit Model

PURPOSE To evaluate whether the combination of radiofrequency (RF) ablation and local injection of the immunostimulant Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces systemic antitumor immunity. MATERIALS AND METHODS Japanese White rabbits with lung and auricle VX2 tumors were randomized into three groups: control (n = 8; no treatment), RF ablation only (n = 8; RF ablation to the lung tumor), and RF ablation with local BCG injection into the lung tumor (n = 8). Treatments were performed 1 week after tumor implantation. Survival was evaluated with Kaplan-Meier method and log-rank test. Weekly mean volume and specific growth rate (SGR) of auricle tumors were calculated, and comparisons were made by Mann-Whitney test. RESULTS Median survival of control, RF-only, and RF/BCG groups were 23, 41.5, and 103.5 days, respectively. Survival was significantly prolonged in the RF-only and RF/BCG groups compared with the control group (P = .034 and P =.003, respectively), but no significant difference was found between the RF-only and RF/BCG groups (P = .279). Only in the RF/BCG group was mean auricle tumor volume decreased 5 weeks after implantation. No significant difference in SGR was found between the control and RF-only groups (P = .959), but SGR in the RF/BCG group was significantly lower than in the control group (P = .005). CONCLUSIONS The combination of RF ablation and local injection of BCG resulted in distant tumor suppression compared with the control group, whereas RF ablation alone did not produce this effect. Therefore, the combination of RF ablation and local injection of BCG may induce systemic antitumor immunity.

Prediction for Improvement of Liver Function after Balloon-Occluded Retrograde Transvenous Obliteration for Gastric Varices to Manage Portosystemic Shunt Syndrome.

PURPOSE To investigate predictive factors and cutoff value of transient elastography (TE) measurements for assessing improvement in liver function after balloon-occluded retrograde transvenous obliteration (BRTO) for gastric varices (GV). MATERIALS AND METHODS Retrospective analysis was performed of 50 consecutive patients followed for > 3 months after BRTO, who had undergone TE before BRTO between January 2011 and February 2015. The correlation between change in liver function (total bilirubin, albumin, and prothrombin time) and baseline liver function values and liver stiffness measurement (LSM) by TE was evaluated by Pearson correlation test. Receiver operating characteristic curves were used to determine cutoff values for discriminating between patients who had improved liver function and patients who did not. The time interval from BRTO to aggravation of esophageal varices (EV) (worsening morphology, development of new varices, or variceal rupture) grouped by cutoff values was also analyzed. RESULTS Serum albumin was significantly improved at 3 months after BRTO (3.57 g/dL vs 3.74 g/dL, P < .001). There was a significant negative correlation between change in albumin and baseline LSM (r = -0.50, P < .001). The best cutoff point for LSM was ≤ 22.9 kPa, with sensitivity and specificity of 78.4% and 69.2%, respectively, for predicting which patients would have improved albumin after BRTO. Among 33 patients, 29 (88%) patients had improved albumin. The 1-year progression rate of EV after BRTO was 13.6% in patients with LSM ≤ 22.9 kPa. CONCLUSIONS The predictive factor for improvement in albumin after BRTO was lower LSM (≤ 22.9 kPa) using TE.

Therapeutic Effects of CT-guided Radiofrequency Ablation with Concurrent Platinum-Doublet Chemotherapy in a Rabbit VX2 Lung Tumor Model.

Purpose To evaluate survival time with concurrent, combined use of radiofrequency ablation (RFA) and one of the commonly used platinum-doublet chemotherapies (cisplatin [CDDP]/paclitaxel [PTX], CDDP/vinorelbine [VNR], CDDP/adriamycin [ADR], or CDDP/pemetrexed [MTA] combinations) by using a rabbit VX2 lung tumor model. Materials and Methods The experiment was approved by the institutional animal care committee. VX2 cells were implanted into the lungs of 60 rabbits randomized into groups treated with supportive care (control group), RFA alone, chemotherapy alone (CDDP/PTX, CDDP/VNR, CDDP/ADR, or CDDP/MTA), or a combination of RFA and chemotherapy (RFA/CDDP/PTX, RFA/CDDP/VNR, RFA/CDDP/ADR, or RFA/CDDP/MTA). RFA was performed and followed by intravenous chemotherapy. Survival time was evaluated by using the Kaplan-Meier method. Results The median survival time of the control, RFA-alone, CDDP/PTX, CDDP/VNR, CDDP/ADR, CDDP/MTA, RFA/CDDP/PTX, RFA/CDDP/VNR, RFA/CDDP/ADR, and RFA/CDDP/MTA groups was 26.5, 40, 39, 26.5, 28, 26, 120, 16.5, 42, and 26.5 days, respectively. Survival of the RFA/CDDP/PTX group was significantly longer than that of the control (P = .0006), CDDP/PTX (P = .0117), and RFA-alone (P = .0495) groups. Survival was also significantly prolonged with combined RFA/CDDP/ADR treatment versus supportive care (P = .026), but not with RFA alone (P = .765) or CDDP/ADR (P = .167). Survival times in the RFA/CDDP/VNR and RFA/CDDP/MTA groups were significantly shorter than that in the RFA-alone group (P = .0282 and P = .0197, respectively). Conclusion The combination of RFA and systemic chemotherapy with CDDP/PTX may benefit survival. However, RFA with systemic CDDP may have a survival disadvantage when combined with VNR or MTA.

A case of postoperative pyopneumothorax following CT-guided radiofrequency ablation for lung cancer with interstitial pneumonia

We report a case of serious complications following computed tomography (CT)-guided radiofrequency ablation (RFA) performed for the treatment of lung cancer with interstitial pneumonia. The patient developed delayed-onset pyopneumothorax, which required 6 months of antibiotic treatment, drainage, and video-assisted thoracoscopic debridement. Although CT-guided RFA is a promising, effective procedure for difficult-to-treat lung cancer, the present case suggests a risk of complications for patients complicated with interstitial pneumonia and warrants caution.

Chest wall temperature during radiofrequency ablation in a normal rabbit lung model

PurposeThe aim of this study was to examine the actual temperature during lung radiofrequency ablation (RFA) and pathological changes due to thermal damage in the pleural tissue of the chest wall in a rabbit model.Material and methodsThe study was conducted on 14 Japanese white rabbits with normal lungs. Under computed tomography guidance, the electrode with a 2-cm expandable tip was inserted into the lower lung lobe and positioned so the tip of the needle touched the thoracic wall upon expansion. A thermometer was inserted 5 mm lateral to the point of electrode insertion. RFA was applied at 30 W (n = 7) or 15 W (n = 7) until maximum impedance (i.e., roll-off) or for 4 min at the longest. Local tissue temperature was recorded. The chest wall was dissected out immediately after RFA for histological examination.ResultsThe mean (± SD) maximum tissue temperature at 30 W (86.7° ± 10.0°C) was not significantly different from that at 15 W (82.1° ± 6.2°C). The mean ablation time to increase tissue temperature to 50°, 60°, and 70°C was faster at 30 W (13, 27, and 49 s, respectively) than at 15 W (13, 56, and 115 s, respectively) (P < 0.05). Histological examination showed pleural sloughing at the point of needle insertion and ring-shaped thermal injury in the chest wall.ConclusionWith rabbit lung RFA near the chest wall, ablation immediately below the pleura resulted in a rise of local tissue temperature to >80°C and thermal injury.

Three-dimensional conformal radiotherapy for locally advanced hepatocellular carcinoma with portal vein tumour thrombosis: evaluating effectiveness of the model for end-stage liver disease (MELD) score compared with the Child–Pugh classification

OBJECTIVE The purpose of this study was to retrospectively evaluate the effectiveness of the model for end-stage liver disease (MELD) score compared with the Child-Pugh classification in patients who received three-dimensional conformal radiotherapy (3D CRT) for hepatocellular carcinoma (HCC) with portal vein tumour thrombosis (PVTT) by analyzing toxicity and prognostic factors. METHODS 56 consecutive patients who had locally advanced HCC with PVTT treated by 3D CRT between September 2007 and April 2013 were retrospectively reviewed. RESULTS The median survival time of all patients was 6.4 months. Receiver-operating characteristic (ROC) analysis identified MELD score = 7.5 [area under the curve (AUC) 0.81] and Child-Pugh score = 6.5 (AUC 0.86) as the best cut-off values for predicting the incidence of complications over Common Terminology Criteria for Adverse Events grade 2. There was no significant difference in the discrimination power between the MELD score and the Child-Pugh score on comparison of the two ROC curves (p = 0.17). On multivariate analysis, age, MELD score and radiotherapy dose were significant prognostic factors for overall survival (p = 0.021, 0.038 and 0.006, respectively). In contrast, the Child-Pugh classification, tumour response, PVTT response and the number of prior interventional radiologic treatments were not significant on multivariate analysis. CONCLUSION This study showed that the best MELD score cut-off value is 7.5 and that the MELD score is a better prognostic factor than the Child-Pugh classification in 3D CRT for HCC with PVTT. ADVANCES IN KNOWLEDGE The MELD score is useful for predicting the risk of severe toxicities and the prognosis of patients treated with 3D CRT for PVTT.