Radiofrequency ablation in patients with interstitial lung disease and lung neoplasm: a retrospective multicenter study.

PURPOSE: To retrospectively investigate the safety and efficacy of percutaneous radiofrequency ablation (RFA) by analyzing results in patients with lung neoplasm accompanied by interstitial lung disease (ILD) on computed tomography (CT) in a multicenter study. MATERIALS & METHODS: Patients with lung neoplasm accompanied by ILD who underwent RFA between April 2002 and October 2017 at seven institutions were investigated. Technical success rate, and local tumor progression (LTP) of ablated tumors were evaluated. Adverse events including acute exacerbation of ILD were also evaluated. Univariate analyses were performed to identify factors associated with acute exacerbation. RESULTS: Forty-nine patients with 64 lung neoplasm (mean diameter, 22.6 mm; range, 4-58 mm) treated in 66 sessions were included. Usual interstitial pneumonia (UIP) pattern on CT was identified in 23 patients (47%). All patients underwent successful RFA. Acute exacerbations were seen in 5 sessions (8%: 7% with UIP pattern, 8% without) in 5 patients, all occurring on or after 8 days (median, 12 days; range, 8-30 days). Three of those 5 patients died of acute exacerbation. Treatment resulted in mortality after 5% of sessions, representing 6% of patients. Pleural effusion and fever ≥38°C after RFA were identified by univariate analysis (p = 0.0012, p = 0.02, respectively) as significant risk factors for acute exacerbation. The cumulative LTP rate was 43% at 1 year. CONCLUSIONS: RFA appears feasible for patients with lung neoplasm complicated by ILD. Acute exacerbation occurred in 8% of patients with symptoms occurring more than 8 days post-ablation and was associated with a 45% mortality rate.

Delineation of the internal iliac vein using MRI with true FISP sequence in patients with locally recurrent rectal cancer: A pilot study using CT/MRI fusion.

PURPOSE: This study assessed the feasibility of using three-dimensional (3D) models of intrapelvic vascular patterns constructed using computed tomography (CT) and magnetic resonance imaging (MRI) fusion data for preoperative planning in patients with locally recurrent rectal cancer. METHODS: Eleven patients scheduled for pelvic exenteration were included. The 3D fusion data of the intrapelvic vessels constructed using CT and MRI with true fast imaging with steady-state precession sequence (True FISP) were evaluated preoperatively. Contrast ratios (CR) between the piriformis muscle and the intrapelvic vessels were calculated to identify a valid modality for 3D modeling and creating CT/MRI fusion-reconstructed volume-rendered images. RESULTS: The CR values of the internal and external iliac arteries were significantly higher on CT images than MR images (CT vs. MRI; 0.63 vs. 0.45, p < 0.01). However, the CR value of the internal iliac vein was significantly higher on MR than CT images (CT vs. MRI; 0.23 vs. 0.55, p < 0.01). CONCLUSIONS: MRI with True FISP yielded high signal-to-noise ratios and aided in delineating the internal iliac vein around the piriformis muscle. More precise 3D models can be constructed using this technique in the future to aid in the resection of locally recurrent rectal cancer.

Risk Factors Causing Hypothyroidism in Patients With Head and Neck Cancer After Radiotherapy Using SIB-VMAT.

BACKGROUND/AIM: We evaluated the incidence of radiation-induced hypothyroidism and its risk factors in patients with head and neck cancer who underwent radiotherapy using simultaneous integrated boost-volumetric-modulated arc therapy (SIB-VMAT). PATIENTS AND METHODS: This retrospective study included 86 patients who received definitive radiotherapy using SIB-VMAT for head and neck cancer. The incidence of ≥ grade 2 hypothyroidism was evaluated. We also evaluated the relationships between hypothyroidism development and clinical factors and thyroid dose-volume parameters. RESULTS: During a median follow-up period of 17 months (range=3-65 months), 31 patients (36.0%, 31/86) developed grade 2 hypothyroidism requiring hormone replacement therapy. No patients experienced ≥ grade 3 hypothyroidism. The cumulative incidences of hypothyroidism at 1 and 2 years after radiation therapy were 24.5% and 38.7%, respectively, with a median onset time of 10.0 months (range=3.0-35.0 months). Thyroid volume (p=0.003), volume of the thyroid spared at 60 Gy (VS60; cut-off value, 5.16 ml; p=0.009), VS70 (cut-off value, 8.0 ml; p=0.007), VS60 equivalent dose in 2 Gy fraction (EQD2; cut-off value, 7.78 ml; p=0.001), and VS70EQD2 (cut-off value, 10.59 ml; p=0.008) were significantly associated with the development of radiation-induced hypothyroidism. CONCLUSION: Radiation-induced hypothyroidism is not rare in patients with head and neck cancer undergoing radiotherapy using SIB-VMAT. Radiation dose-volume parameters detected in this study may be useful indicators to prevent this complication.

Radiofrequency Ablation Combined with Hepatic Artery Embolization Using a Tris-acryl Gelatin Microsphere for Colorectal Liver Metastases-Initial Experience.

Purpose: We aim to evaluate retrospectively the feasibility, safety, and initial therapeutic outcomes of radiofrequency ablation combined with hepatic artery embolization using a tris-acryl gelatin microsphere for colorectal liver metastases. Material and Methods: Six consecutive patients (4 men and 2 women) with median age of 68 years (range 57-78 years) underwent computed tomography fluoroscopy-guided radiofrequency ablation immediately after hepatic artery embolization using microspheres. This study evaluated tumor visibility on noncontrast-enhanced computed tomography immediately after hepatic artery embolization; analyzed local tumor progression; defined technical success as the coverage of the tumor by the ablative zone; and assessed adverse events based on Common Terminology Criteria for Adverse Events v5.0. Results: Ten tumors with median maximum diameter of 9 mm (range 5-52 mm) were treated in nine sessions. Eight tumors (80%, 8/10 tumors) were detected as high-attenuation nodules. One tumor was treated in two sessions because follow-up computed tomography revealed an insufficient ablative margin. Therefore, the primary and secondary technical success was 90% (9/10 tumors) and 100% (10/10 tumors), respectively. Grade 2 pneumothorax was observed in one session (11%, 1/9 sessions). No grade 3 or higher adverse event was observed. The local tumor progression rate was 20% (2/10 tumors) during the median follow-up of 14 months. Conclusions: Radiofrequency ablation following microsphere embolization may be a feasible, safe, and useful therapeutic option for controlling small colorectal liver metastases.

Lenvatinib Mitigates Transarterial Embolization-Induced Polarization of Tumor-Associated Macrophages in a Rat Hepatocellular Carcinoma Model.

PURPOSE: To investigate the effect of transarterial embolization (TAE) on macrophage polarization and the modulatory effect of lenvatinib when used in combination with TAE in a rat hepatocellular carcinoma model. MATERIALS AND METHODS: A N1S1-bearing orthotopic rat model was subjected to TAE and administered 5 mg/kg of lenvatinib. CD8+, CD68+, and CD206+ cells were examined in 4 groups: sham (n = 5), lenvatinib (n = 5), TAE (n = 5), and combination of TAE and lenvatinib (n = 5). Transcriptome analysis was performed to assess gene expression related to macrophage polarization in the sham, TAE, and combination groups. An in vitro coculture experiment with bone marrow-derived macrophages was performed to identify lenvatinib target in macrophage polarization. RESULTS: There were no significant differences in the number of CD8+ and CD68+ cells among the 4 groups. Tumor-associated macrophage positivity for CD206 was significantly higher in the TAE group (58.1 ± 20.9) than in the sham (11.2 ± 14.3; P < .001) and combination (27.1 ± 19.7; P = .003) groups. In the transcriptome analysis, compared with the genes in the sham group, 5 macrophage polarization-related genes, including St6gal1, were upregulated by more than 1.5 fold in the TAE group and downregulated by more than 1.5 fold in the combination group. The coculture experiment showed that lenvatinib did not affect macrophages but affected N1S1 cells, leading to macrophage polarization. CONCLUSIONS: TAE-induced M2 macrophage polarization. Lenvatinib administration with TAE could reprogram macrophage polarization, improving tumor immune microenvironment.

Efficacy of Percutaneous Direct Puncture Biopsy of Malignant Lung Tumors Contacting to the Pleura.

BACKGROUND/AIM: This is a retrospective evaluation of whether percutaneous direct puncture biopsy of lung lesions contacting to the pleura is justified. PATIENTS AND METHODS: Between August 2016 and July 2021, 163 consecutive patients (100 males, 63 females with a median age of 73 years) who had malignant lung tumors measuring 0.6-12.4 cm (median, 2.9 cm) that contacted to the pleura and underwent percutaneous lung biopsy under computed tomography fluoroscopic guidance using an 18-gauge end-cut needle were examined. The trajectory was direct puncture in 80 patients (49.1%, 80/163), and trans-lung in 83 patients (50.9%, 83/163). Diagnostic yield and major adverse event rates of direct and trans-lung puncture biopsies were compared. RESULTS: No difference was found in diagnostic yield between direct puncture and trans-lung biopsies (93.8% vs. 98.8%, p=0.11). Major adverse events were major pneumothorax (n=13/163, 8.0%), pleural dissemination (n=18/163, 11.0%), and hemothorax requiring arterial embolization (n=1/163, 1.0%). Direct puncture caused major pneumothorax significantly less than trans-lung puncture did (0%, 0/80 vs. 15.7%, 13/83, p<0.001). No significant difference was found between the two biopsy methods regarding the incidence of pleural dissemination (11.0%, 11/80 vs. 8.4%, 7/83, p=0.32). CONCLUSION: Direct puncture biopsy of malignant lung tumors contacting to the pleura is justified.

Untangling a Knotted Angiographic Catheter Using a Balloon Catheter: A Case Report.

When a 66-year-old man with hepatocellular carcinoma underwent an angiographic examination, a 4-Fr catheter was inserted from the right femoral artery. It became tightly knotted in the descending aorta. To untangle the knotted catheter, a noncompliant balloon catheter was delivered into the knotted loop from the contralateral femoral artery. After the balloon catheter was inflated from the inside of the knotted loop, the knot became loose. Finally, the knotted catheter was untangled. Subsequently, the remainder of the examination was performed as initially planned.

Clinical Utility of Bland Embolization Using Microspheres for Painful Malignant Musculoskeletal Tumors.

BACKGROUND/AIM: To evaluate retrospectively whether bland embolization using microspheres is safe and useful for relieving pain in patients with painful malignant musculoskeletal (MSK) tumors. PATIENTS AND METHODS: Bland embolization using microspheres was performed for 20 patients (11 women/9 men) with a median age of 69 years (range=40-89 years) who had 22 painful malignant MSK tumors. The maximum tumor diameters were 2.4-13.8 cm (median, 7.5 cm). Pain was evaluated using the visual analog scale. A decrease of this score by 2 or more after embolization was defined as clinically effective pain relief. Adverse events (AEs) were evaluated using CTCAE v5.0. Objective response, disease control rates, and overall survival were also evaluated. RESULTS: Effective pain relief was achieved in 18 patients (90.0%, 18/20). Grade-3 AEs developed in four patients (20.0%, 4/20): skin ulcer (n=2), skin ulcer and pain (n=1), and muscle weakness with dysesthesia (n=1). No grade-4 or grade-5 AEs developed. Objective response and disease control rates were 26.7% (4/15) and 86.7% (13/15), respectively. The 1-year survival rate was 43.8%, with median survival of 9.2 months (range=0.5-41.0 months). CONCLUSION: Although the survival benefit is equivocal, bland embolization is acceptably safe and useful for relieving pain by controlling tumor growth in patients with painful malignant MSK tumors.

Radioprotective Effects of a Semicircular X-ray Shielding Device for Operators During CT Fluoroscopy-Guided Interventional Procedures: Experimental and Clinical Studies.

PURPOSE: To evaluate, experimentally and clinically, the radioprotective effects of a semicircular X-ray shielding device for operators during CT fluoroscopy-guided IR procedures. MATERIALS AND METHODS: During experimentation, the reduction rates of scattered radiation rates from CT fluoroscopy were evaluated using a humanoid phantom. Two shielding device positions were tested: "shielding close to the CT gantry" and "shielding close to the operator". The scattered radiation rate without shielding was also evaluated. The clinical study retrospectively evaluated the operator's radiation exposure during 314 CT-guided IR procedures. With a semicircular X-ray shielding device (with shielding group, n = 119) or without it (no shielding group, n = 195), CT fluoroscopy-guided IR procedures were performed. Radiation dose measurements were taken using a pocket dosimeter placed near the operator's eye. For shielding and no shielding groups, the procedure time, dose length product (DLP), and the operator's radiation exposures were compared. RESULTS: Experimentation revealed the respective mean reduction rates of "shielding close to the CT gantry" and "shielding close to the operator" as 84.3% and 93.5% compared with the no-shielding setting. Although no significant differences were found in the procedure time and the DLP between "no shielding" and "with shielding" groups in the clinical study, the operators' radiation exposure in the "with shielding" group (0.03 ± 0.04 mSv) was significantly lower than in the "no shielding" group (0.14 ± 0.15 mSv; p < .001). CONCLUSION: The semicircular X-ray shielding device provides valuable radioprotective effects for operators during CT fluoroscopy-guided IR.

Liver regeneration after portal vein embolization: comparison between absolute ethanol and N-butyl-cyanoacrylate in an in vivo rat model.

PURPOSE: To compare the effects of absolute ethanol (ethanol) and N-butyl-cyanoacrylate (NBCA) on non-embolized liver lobe regeneration in a rat model. METHODS: Twenty-seven Sprague-Dawley rats underwent portal vein embolization (PVE) using ethanol:lipiodol, 1:1 (ethanol group, n = 11, 40.74%), NBCA:lipiodol, 1:1 (NBCA group, n = 11, 40.74%), or sham treatment (sham group, n = 5, 18.52%). The non-embolized and embolized lobe-to-whole liver weight ratios 14 days after PVE were compared among the groups (n = 5, 18.52%). The expressions of CD68 and Ki-67 and embolized-lobe necrotic area percentages one day after PVE were compared between the ethanol (n = 3, 11.11%) and NBCA (n = 3, 11.11%) groups. RESULTS: The non-embolized lobe-to-whole liver weight ratio after PVE was significantly higher in the NBCA group (n = 5, 33.33%) than in the ethanol group (n = 5, 33.33%) (84.28% ± 1.53% vs. 76.88% ± 4.12%, P = 0.029). The embolized lobe-to-whole liver weight ratio after PVE was significantly lower in the NBCA group than in the ethanol group (15.72% ± 1.53% vs. 23.12% ± 4.12%, P = 0.029). The proportions of CD68- and Ki-67-positive cells in the non-embolized lobe after PVE were significantly higher in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [60 (48-79) vs. 55 (37-70), P = 0.003; 1 (0-2) vs. 1 (0-2), P = 0.004]. The embolized-lobe necrotic area percentage after PVE was significantly larger in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [29.46 (12.56-83.90%) vs. 16.34 (3.22-32.0%), P < 0.001]. CONCLUSION: PVE with NBCA induced a larger necrotic area in the embolized lobe and promoted greater non-embolized liver lobe regeneration compared with PVE with ethanol.

Optimal threshold of a control parameter for tomotherapy respiratory tracking: A phantom study.

BACKGROUND: Radixact Synchrony® , a real-time motion tracking and compensating modality, is used for helical tomotherapy. Control parameters are used for the accurate application of irradiation. Radixact Synchrony® uses the potential difference, which is an index of the accuracy of the prediction model of target motion and is represented by a statistical prediction of the 3D distance error. Although there are several reports on Radixact Synchrony® , few have reported the appropriate settings of the potential difference threshold. PURPOSE: This study aims to determine the optimal threshold of the potential difference of Radixact Synchrony® during respiratory tumor-motion-tracking irradiation. METHODS: The relationship among the dosimetric accuracy, motion tracking accuracy, and control parameter was evaluated using a moving platform, a phantom with a basic respiratory model (the fourth power of a sinusoidal wave), and several irregular respiratory model waveforms. The dosimetric accuracy was evaluated by gamma analysis (3%, 1 mm, 10% dose threshold). The tracking accuracy was measured by the distance error of the difference between the tracked and driven positions of the phantom. The largest potential difference for 95% of treatment time was evaluated, and its correlation with the gamma-pass ratio and distance error was investigated. The optimal threshold of the potential difference was determined by receiver operating characteristic (ROC) analysis. RESULTS: A linear correlation was identified between the potential difference and the gamma-pass ratio (R = -0.704). A linear correlation was also identified between the potential difference and distance error (R = 0.827). However, as the potential difference increased, it tended to underestimate the distance error. The ROC analysis revealed that the appropriate cutoff value of the potential difference was 3.05 mm. CONCLUSION: The irradiation accuracy with motion tracking by Radixact Synchrony® could be predicted from the potential difference, and the threshold of the potential difference should be set to ∼3 mm.

Impact of the Ablative Margin on Local Tumor Progression after Radiofrequency Ablation for Lung Metastases from Colorectal Carcinoma: Supplementary Analysis of a Phase II Trial (MLCSG-0802).

PURPOSE: To explore what extent of ablative margin depicted by computed tomography (CT) immediately after radiofrequency (RF) ablation is required to reduce local tumor progression (LTP) for colorectal cancer (CRC) lung metastases. MATERIALS AND METHODS: This retrospective study was undertaken as a supplementary analysis of a previous prospective trial. Seventy patients (49 men and 21 women; mean age ± standard deviation, 64.9 years ± 10.6 years) underwent RF ablation for CRC lung metastases, and 95 tumors that were treated in the trial and followed up with CT at least 12 months after RF ablation were evaluated. The mean tumor size was 1.0 cm ± 0.5 cm. The ablative margin was estimated as the shortest distance between the outer edge of the tumor and the surrounding ground-glass opacity on CT obtained immediately after RF ablation. The impact of the ablative margin on LTP was evaluated using logistic regression analysis. Multivariate logistic regression analysis was also performed to identify the risk factors for LTP. The result was validated with multivariate logistic regression applying a bootstrap method (1,000 times resampling). RESULTS: The mean ablative margin was 2.7 mm ± 1.3 (range, 0.4-7.3 mm). LTP developed in 6 tumors (6%, 6/95) 6-19 months after RF ablation. The LTP rate was significantly higher when the margin was less than 2 mm (P = .023). A margin of <2 mm was also found to be a significant factor for LTP (P = .048) on multivariate analysis and validated using the bootstrap method (P = .025). CONCLUSIONS: An ablative margin of at least 2 mm is important to reduce LTP after RF ablation for CRC lung metastases.

Clinical Experience of Percutaneous Radiofrequency Ablation Using an arfa RF ABLATION SYSTEMⓇ in Various Organs.

Purpose: To evaluate the feasibility, safety, and efficacy of radiofrequency (RF) ablation using an ablation system (arfa RF ABLATION SYSTEMⓇ; Japan Lifeline Co. Ltd.) for treating solid tumors in various organs. Material and Methods: Between October 2019 and August 2021, 80 patients (29 women, 51 men; median age, 70.0 yr) underwent 107 RF ablation sessions using the ablation system to treat 151 tumors in the liver (n = 86), lung (n = 51), adrenal gland (n = 4), pleura (n = 4), bone (n = 3), lymph node (n = 2), and kidney (n = 1). The maximum tumor diameter was 2-40 mm (median, 11 mm). This study evaluated technical success (defined as the completion of planned RF ablation), technique efficacy (defined as the complete tumor ablation on follow-up images), and adverse events. Local tumor progression in 146 curatively treated malignant tumors was evaluated. Results: The technical success rate was 100% (107/107). Ablation zones in two tumors were insufficient. Therefore, the primary technique efficacy rate was 98.1% (105/107). Grade 3 hepatic infarction (1.6%, 1/64) and grade 4 pleuritis (3.4%, 1/29) occurred respectively after liver and lung RF ablation. During the median follow-up period of 10.2 months (Interquartile range, 4.2 and 16.4 months), local tumor progression developed in two tumors (1.4%, 2/146). Conclusions: The arfa RF ABLATION SYSTEMⓇ is a feasible, safe, and effective RF ablation device for managing solid tumors in various organs.

Differentiation of Angiomyolipoma With Minimal Fat from Clear Cell Renal Cell Carcinoma Using Non-contrast Multiparametric Magnetic Resonance Imaging.

BACKGROUND/AIM: This study was conducted to ascertain the optimal combination of non-contrast magnetic resonance (MR) imaging sequences for the differential diagnosis between small angiomyolipoma (AML) with minimal fat and clear cell renal cell carcinoma (CCRCC). PATIENTS AND METHODS: Thirty-nine patients with pathologically proven AML with minimal fat (n=6) or CCRCC (n=33) measuring 4 cm or less were included. All underwent MR imaging before partial nephrectomy or percutaneous biopsy. Four quantitative parameters of tumors were evaluated: signal intensity (SI) index of T1W- gradient-echo imaging, SI index of T2- fat suppression imaging (T2-SI index), apparent diffusion coefficient (ADC) value, and standard deviation (SD) of ADC. These quantitative parameters were compared using Wilcoxon rank-sum test and receiver operating characteristic (ROC) curve analyses. The optimal combination of quantitative parameters was sought using logistic regression analysis. RESULTS: Comparison of quantitative parameters showed that the T2-SI index (median, AML with minimal fat vs. CCRCC; 0.74 vs. 1.27, p<0.001), ADC value (1.12 vs. 1.75, p=0.005), and SD of ADC (104 vs. 233, p<0.001) were significantly lower in AML with minimal fat than CCRCC. From the ROC curve analysis, the highest area under the curve (1.000; 100% sensitivity; 100% specificity) was obtained using the logistic regression model with the SD of ADC and T2-SI index or ADC value as explanatory variables. CONCLUSION: SD of ADC combined with T2-SI index or ADC value exhibited the highest diagnostic performance for differentiating small AML with minimal fat from CCRCC.

Protective Effect of Polaprezinc and Hyperbaric Oxygen Therapy on Radiation-induced Small Intestinal Damage in Mice.

BACKGROUND/AIM: To investigate the effect of polaprezinc (antioxidant) administration and hyperbaric oxygen therapy on radiation-induced intestinal injury. MATERIALS AND METHODS: Forty-five C57BL/6J mice underwent total body radiation of 2 Gy. Polaprezinc was given in 12 mice, hyperbaric oxygen in 12 mice, and both in 12 mice. The other 9 mice did not undergo any treatment. Mice were sacrificed 2, 4, and 6 h after radiation, and 9 specimens (3 each from the duodenum, jejunum, and ileum) were harvested. Apoptotic intestinal crypt cells were histologically evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. RESULTS: Apoptotic cell number per 1,000 crypt cells was 31.0±6.7 at 2 h, 28.4±5.2 at 4 h, and 32.9±5.1 at 6 h in the mice group treated by radiation alone. Both polaprezinc administration and hyperbaric oxygen therapy significantly suppressed apoptosis. Although the effect of polaprezinc administration on suppressing apoptosis became less over time (4.9±5.7 and 19.4±13.2 at 2 and 6 h, respectively), that of hyperbaric oxygen therapy was stable regardless of time (23.6±4.8 and 25.8±4.1 at 2 and 6 h). Administration of both polaprezinc and hyperbaric oxygen showed a significant synergetic or additive effect on suppressing apoptosis at 6 h (11.4±10.5, p<0.0035 vs. polaprezinc, p<0.0001 vs. hyperbaric oxygen). CONCLUSION: Both polaprezinc administration and hyperbaric oxygen therapy are effective in relieving radiation-induced small intestinal damage, and a synergistic or additive effect is expected when using both.

Lymphangiography as a Treatment for Refractory Congenital Chylothorax Due to RASopathies: A Report of Two Cases.

In this study, we report two cases in which intranodal lymphangiography helped improve congenital chylothorax due to RASopathies. We performed lymphangiography after conservative treatments failed to improve chylothorax in an 8-year-old girl with cardiofaciocutaneous syndrome and a 2-month-old boy with Noonan syndrome. Inguinal lymph nodes were punctured with 25-gauge needles under ultrasonographic guidance, and 4 and 1 mL of iodized oil were injected, respectively, showing a backflow of iodized oil into the lungs. Chylothorax had improved in both patients after nodal lymphangiography. However, the second child experienced worsening of disease-associated extremity edema and died of sepsis 4 months later.

Use of Microballoon Catheter in Transarterial Ethanol Embolization of Renal Angiomyolipoma: A Retrospective Comparative Study with Historical Control?

Purpose: To clarify the utility of microballoon catheter in renal arterial ethanol embolization of renal angiomyolipoma (AML). Material and Methods: A total of 20 patients (15 women, 5 men) with median age of 45 years (39-60 years) underwent embolization to treat 22 AMLs. A mixture of ethanol and iodized oil was injected into the feeding arteries of 13 tumors using balloon occlusion (the balloon embolization group) with a microballoon catheter and 9 tumors without using balloon occlusion (the non-balloon embolization group). Changes in the maximum tumor diameter, tumor volume, and adverse events were evaluated. Result: The median baseline maximum tumor diameters and volumes were 6.3 cm and 61.4 cm3 in the balloon embolization group, and 4.6 cm and 40.1 cm3 in the non-balloon embolization group, respectively. Tumor enhancement disappeared on postembolization angiography in all cases. All tumors shrunk after embolization. There were no statistically significant differences in the percent decrease in the maximum tumor diameter and volume at 10-12 month between balloon occlusion group (31.5% and 67.9%) and control group (34.8% and 62.6%). Fever was significantly more frequent when balloon occlusion was used: 38% vs. 0% (p = 0.03). No major complication was observed in either patient group. Conclusions: Balloon occlusion may not affect tumor shrinkage when embolizing AMLs with a mixture of ethanol and lipiodol.

Error Detectability of Isodose Volumes as ROIs in Prostate Intensity-modulated RT QA.

BACKGROUND/AIM: To evaluate the quality of error detectability with a three-dimensional verification system using isodose volumes as regions of interest (ROIs) in quality assurance (QA) of intensity-modulated radiation therapy. PATIENTS AND METHODS: Treatment plans with four types of intentional errors were created from the data of 20 patients with localized prostate cancer. These plans underwent QA using the three-dimensional verification system. The datasets of another 30 cases without inserted errors were assessed as controls. The ROIs used in the evaluations were those used in our conventional method (planning target volume, rectum, and bladder). The isodose volume method (5%, 50% and 95% isodose volume) and the error detection rates (measurement above the tolerance values, as set from the other 30 cases) were assessed and compared. RESULTS: There was significantly higher multileaf collimator systematic closed error detectability with the isodose volume method compared to the conventional method (A-side 0.2 mm: p=0.005, A-side 0.35 mm: p=0.002, B-side 0.2 mm: p=0.001 and B-side 0.35 mm: p=0.010). There were no error types for which the error detection rate of the isodose volume method was lower than that of the conventional method. CONCLUSION: The isodose volume method was able to evaluate the irradiated ROIs that could be delineated, and improved error detectability. This method has the potential to provide a wider margin of safety in intensity-modulated radiation therapy.

How Compatible Are Immune Checkpoint Inhibitors and Thermal Ablation for Liver Metastases?

Cancer immunotherapy, which reactivates the weakened immune cells of cancer patients, has achieved great success, and several immune checkpoint inhibitors (ICIs) are now available in clinical practice. Despite promising clinical outcomes, favorable responses are only observed in a fraction of patients, and resistance mechanisms, including the absence of tumor antigens, have been reported. Thermal ablation involves the induction of irreversible damage to cancer cells by localized heat and may result in the release of tumor antigens. The combination of immunotherapy and thermal ablation is an emerging therapeutic option with enhanced efficacy. Since thermal ablation-induced inflammation and increases in tumor antigens have been suggested to promote the cancer-immunity cycle, the combination of immuno-oncology (IO) therapy and thermal ablation may be mutually beneficial. In preclinical and clinical studies, the combination of ICI and thermal ablation significantly inhibited tumor growth, and synergistic antitumor effects appeared to prolong the survival of patients with secondary liver cancer. However, evidence for the efficacy of ICI monotherapy combined with thermal ablation is currently insufficient. Therefore, the clinical feasibility of immune response activation by ICI monotherapy combined with thermal ablation may be limited, and thermal ablation may be more compatible with dual ICIs (the IO-IO combination) to induce strong immune responses.

Long-term survival following radiofrequency ablation of lung metastases in an elderly patient with calcaneal osteosarcoma: A case report and review of the literature.

RATIONALE: Recently, the number of osteosarcomas has been increasing in elderly patients due to human longevity. Lung metastases are the primary cause of death from osteosarcomas. Complete resection of lung metastases can prolong the survival. However, complete resection in elderly patients is often difficult due to high risk of operative complications. Computed tomography (CT) guided radiofrequency ablation (RFA) is a minimally invasive technique to destroy tumor nodules using heat. In this report, we present the first case older than 65 years applying RFA for lung metastases due to osteosarcoma. PATIENT CONCERNS: A 74-year-old male presented with 1-year history of heel pain. A conventional high-grade osteosarcoma in his calcaneus was diagnosed. Below-knee amputation was performed. However, lung metastases were found in both lungs 1 year after amputation. CT-guided lung RFA was chosen since surgical intervention for lung metastases was abandoned because of tumor multiplicity and medical comorbidities. A total of 18 lung metastases were treated by CT-guided RFA. The most frequent complication was pneumothoraxes in 4 of 8 (50%) procedures and chest tube drainage was required in 2 of these (2 of 8 (25%) procedures). DIAGNOSES: Six lung metastases of osteosaroma were found in both lungs at 1 year after surgery. INTERVENTIONS: CT-guided lung RFA was performed. A total of 18 lung metastases were treated in 8 lung RF procedures. OUTCOMES: The patient has been alive with disease for 5.5 years after the initial surgery. LESSONS: CT-guided lung RFA is effective for elderly patients with osteosarcoma lung metastases in spite of discouragement of lung metastasectomy due to multiplicity of metastases and medical-comorbidities.