Superselective particle embolization enhances efficacy of radiofrequency ablation: effects of particle size and sequence of action. Cardiovasc Intervent Radiol. 2013;36:773-782. [PMID: 23070107 DOI: 10.1007/s00270-012-0497-7]

A case report of sarcoma recurrence treated with a balloon-occluded combined approach (b-MWA + b-TAE)

Sarcomas present challenges in management due to their aggressive nature. Interventional radiology, utilizing ablation and embolization, offer promising alternatives for recurrent cases. In recent years, combined techniques (ablation + embolization) and the use of balloon-microcatheter have been introduced to enhance the necrotic effect in HCC treatment. This paper presents the case of a 47-year-old female with recurrent abdominal sarcoma treated with balloon-occluded microwave ablation (b-MWA) and balloon-occluded transarterial embolization (b-TAE). Post-treatment imaging revealed a significant reduction in lesion size and absence of pathological contrast enhancement. This study highlights the potential of balloon-catheter-assisted combined therapies (b-MWA + b-TAE) in managing sarcomas, expanding the applicability of interventional radiology for inoperable cases that are too large for ablative therapy alone or requiring multiple antennas. Further research is warranted to refine protocols and enhance patient outcomes in sarcoma management.

Evidence-based medical oncology and interventional radiology paradigms for liver-dominant colorectal cancer metastases

Colorectal cancer metastasizes predictably, with liver predominance in most cases. Because liver involvement has been shown to be a major determinant of survival in this population, liver-directed therapies are increasingly considered even in cases where there is (limited) extrahepatic disease. Unfortunately, these patients carry a known risk of recurrence in the liver regardless of initial therapy choice. Therefore, there is a demand for minimally invasive, non-surgical, personalized cancer treatments to preserve quality of life in the induction, consolidation, and maintenance phases of cancer therapy. This report aims to review evidence-based conceptual, pharmacological, and technological paradigm shifts in parenteral and percutaneous treatment strategies as well as forthcoming evidence regarding next-generation systemic, locoregional, and local treatment approaches for this patient population.

Ex Vivo Liver Experiment of Hydrochloric Acid-Infused and Saline-Infused Monopolar Radiofrequency Ablation: Better Outcomes in Temperature, Energy, and Coagulation

OBJECTIVE

To compare temperature, energy, and coagulation between hydrochloric acid-infused radiofrequency ablation (HAIRFA) and normal saline-infused radiofrequency ablation (NSIRFA) in ex vivo porcine liver model.

MATERIALS AND METHODS

30 fresh porcine livers were excised in 60 lesions, 30 with HAIRFA and the other 30 with NSIRFA. Both modalities used monopolar perfusion electrode connected to a RF generator set at 103 °C and 30 W. In each group, ablation time was set at 10, 20, or 30 min (10 lesions from each group at each time). We compared tissue temperatures (at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 cm away from the electrode tip), average power, deposited energy, deposited energy per coagulation volume (DEV), coagulation diameters, coagulative volume, and spherical ratio between the two groups.

RESULTS

Temperature-time curves showed that HAIRFA provided progressively greater heating than that of NSIRFA. At 30 min, mean average power, deposited energy, coagulation volumes (113.67 vs. 12.28 cm(3)) and diameters, and increasing in tissue temperature were much greater with HAIRFA (P < 0.001 for all), except DEV was lower (456 vs. 1396 J/cm(3), P < 0.001). The spherical ratio was closer to 1 with HAIRFA (1.23 vs. 1.46). Coagulation diameters, volume, and average power of HAIRFA increased significantly with longer ablation times. While with NSIRFA, these characteristics were stable till later 20 min, except the power decreased with longer ablation times.

CONCLUSIONS

HAIRFA creates much larger and more spherical lesions by increasing overall energy deposition, modulating thermal conductivity, and transferring heat during ablation.

Radiofrequency ablation combined with transcatheter therapy in rabbit VX2 liver tumors: effects and histopathological characteristics

BACKGROUND

Transarterial chemoembolization (TACE) combined with radiofrequency ablation (RFA) treatment (TACE-RFA) has been confirmed superior to TACE or RFA alone in animal liver tumors. TACE before RFA was shown to increase hepatocellular damage. Further optimization of the combination strategy for transcatheter arterial embolization (TAE) or TACE combined with RFA is warranted.

PURPOSE

To determine the optimal strategy for radiofrequency ablation combined with transcatheter therapies in VX2 liver tumors in a rabbit model.

MATERIAL AND METHODS

Twenty-four Japanese White rabbits with VX2 liver tumors were randomly divided into four groups: TACE-RFA (TACE-RFA group), transcatheter arterial embolization (TAE) combined with RFA treatment (TAE-RFA group), RFA only group, and TACE only group. Blood samples were collected 1 day before the operation and at 3 and 7 days postoperatively. Seven days after the operation, maximal diameters of coagulation or infarcted zones in the gross specimens, CT images, histopathological characteristics, tumor necrotic rate, and growth rate were compared.

RESULTS

Significantly larger mean long-axis (P < 0.05) and short-axis (P < 0.05) diameters of coagulation and infarction were observed in the TACE-RFA group compared with the TAE-RFA, RFA, and TACE groups on day 7; and the TAE-RFA group showed a significant (P < 0.05) increase versus the RFA and TACE groups on day 7. There were no significant differences in tumor growth rate (109.3 ± 37.5 vs. 119.0 ± 43.1%, P = 0.45) and necrotic rate (89.5 ± 12.0 vs. 83.5 ± 9.3%, P = 0.73) between the TACE-RFA and TAE-RFA groups. TACE-RFA was more effective for achieving tumor destruction than the other treatment strategies, but led to increased rabbits discomfort and more severe liver dysfunction compared with TAE-RFA.

CONCLUSION

TAE-RFA appears to be a beneficial therapeutic modality for treating VX2 liver tumors in a rabbit model.

Enhancement of radiofrequency ablation of the liver combined with transarterial embolization using various embolic agents

PURPOSE

Reducing blood flow in the liver during radiofrequency ablation causes enlargement of the ablation area. In this animal study, we evaluated the extended effects of radiofrequency ablation combined with transarterial embolization using various embolic agents.

METHODS

We treated 38 radiofrequency ablation lesions after embolization in 13 pigs using the following embolic agents: gelatin sponge (Group A); iodized oil followed by gelatin sponge (Group B); 700-900 µm calibrated microspheres (Group C); and 100-300 µm calibrated microspheres (Group D). Lesion size and pathological evaluations of these ablation lesions were compared with those receiving radiofrequency ablation alone (control).

RESULTS

Both the long- and short-axis diameters of the ablation lesions for Groups A, B, C, and D were significantly longer than those of controls (long axis/short axis for Groups A, B, C, D, and controls were 27.2/23.2, 30.2/26.0, 28.2/22.2, 32.0/24.4, and 23.2 mm/18.5 mm, respectively) (P < 0.05). The long-axis of the ablation lesion for Group D was significantly longer than those for both Groups A and C (P < 0.05). At pathological examination, the central ablation lesions showed coagulative necrosis with a surrounding hemorrhagic rim, and the microspheres were fitted to occlude the small arteries in peripheral liver parenchyma in Groups C and D.

CONCLUSIONS

The extended effects of embolization with small microspheres may be stronger than those with large microspheres and were equal to those with iodized oil followed by gelatin sponge.

Role of combined embolization and ablation in management of renal masses

Combination of minimally invasive treatment modalities is being increasingly utilized to improve local tumor control and overall survival. In the liver, the combination of embolization and ablation results in equivalent overall survival and intrahepatic disease progression as surgical resection for lesions smaller than 7 cm. Ablation alone for small renal masses up to 4 cm results in excellent local tumor control and lack of residual enhancement to suggest viable tumor. A small number of studies have been performed combining embolization and ablation, which result in high rates of local tumor control for tumors smaller than 5 cm. Based on this small cohort, combined embolization and ablation may be most indicated for central or mixed tumors where ablation alone suffers from the greatest degree of "heat sink" effect. This article reviews the theory, methods, and outcomes of combining percutaneous ablative and embolic modalities in the treatment of renal masses.

Repeated bland-TAE using small microspheres injected via an implantable port-catheter system for liver metastases: an initial experience

PURPOSE

The purpose of this pilot study was to assess the effectiveness of repeated bland-TAE using small-size microspheres for liver metastases. To date, there have been no publications as to whether bland-TAE could be effective for nonhypervascular liver tumors.

METHODS

Bland-TAE with 100-μm, calibrated microspheres was performed in two chemoresistant patients: one with colorectal metastases and the other with gastric metastases. Both patients had multiple tumors in the entire liver. An implantable port-catheter system was placed in the hepatic artery to conduct repeated embolizations, thereby achieving enough efficacies. Microspheres were injected via the port until the disappearance of the tumor stains. Angiographies via the port were conducted 1, 3, 7, and 14 days after bland-TAE to evaluate the patency of the hepatic artery.

RESULTS

The hepatic artery started to recanalize 1 day after TAE and tumor stains appeared again during the 14 days. In both patients, bland-TAE was repeated four times in intervals of 14-21 days. The enhanced CTs showed necrotic changes and the decrease in size of the tumors. The serum CEA level decreased from 2,989 to 70 ng/ml and from 174 to 48 ng/ml, respectively. Bilomas and a liver abscess developed as complications.

CONCLUSIONS

Repeated bland-TAE using 100-μm microspheres injected via an implantable port-catheter system could be effective for liver metastases, although the caution of biliary injury is needed.