Extension of radiofrequency ablation of the liver by transcatheter arterial embolization with iodized oil and gelatin sponge: results in a pig model

Combined transarterial chemoembolization and radiofrequency ablation for subphrenic versus nonsubphrenic hepatocellular carcinoma: a propensity score matched study

PURPOSE

To compare therapeutic outcomes of combined transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) treatment for small hepatocellular carcinoma (HCC) in subphrenic versus nonsubphrenic locations by propensity score matching.

METHODS

This retrospective study included 293 patients with single HCC (≤ 3 cm) ineligible for ultrasound-guided RFA who received iodized oil TACE and subsequent RFA between June 2010 and January 2017. The patients were divided into two groups according to the tumor location: subphrenic (n = 99) and nonsubphrenic (n = 194). Subphrenic HCC was defined as a tumor abutting the diaphragm. Local tumor progression (LTP) and overall survival (OS) rates were compared by propensity score matching. Procedure-related complications were also assessed.

RESULTS

Matching yielded 93 matched pairs of patients. In the matched cohorts, cumulative 1-, 3-, and 5-year LTP rates were 5.4%, 12.1%, and 12.1% in the subphrenic group and 1.1%, 7.5%, and 8.6% in the nonsubphrenic group, respectively, with no significant differences (p = 0.278). Corresponding OS rates were 100%, 80.2%, and 71.3% in the subphrenic group and 97.9%, 88.1%, and 75.6% in the nonsubphrenic group, respectively, with no significant differences (p = 0.308). The subphrenic location was not a significant risk factor for LTP and OS in multivariate analysis. There were no significant differences in complication rates between the two groups (p > 0.05).

CONCLUSION

The therapeutic outcomes of combined TACE and RFA for small subphrenic HCC were similar to those for nonsubphrenic HCC. The combination therapy seems to be an effective and safe method in treating small subphrenic HCC.

Therapy of Intermediate-Stage Hepatocellular Carcinoma: Current Evidence and Clinical Practice

Intermediate-stage Hepatocellular Carcinoma (HCC) represents a wide range of disease burden. Patients with different levels of liver function, tumor size, and number of lesions may all have intermediate-stage disease according to the Barcelona Clinic Liver Cancer (BCLC) staging system. Several minimally invasive image-guided locoregional therapies are available for the treatment of intermediate-stage HCC, including conventional transarterial chemoembolization (cTACE), drug-eluting bead TACE (DEB-TACE), yttrium-90 radioembolization (Y-90 RE), thermal ablation, bland embolization, and combination therapy. Available clinical evidence points to cTACE as the current gold standard for the locoregional treatment of intermediate-stage HCC. DEB-TACE is at best non-inferior to cTACE in terms of survival benefit. Y-90 RE is a maturing therapy, and some institutions have adopted it as first-line therapy for intermediate-stage HCC. Thermal ablation combined with TACE may be used in select patients, while bland embolization has only limited evidence for its use. The combination of locoregional therapy with VEGF inhibitors or immune checkpoint inhibitors has also been explored. This article will examine in detail the clinical evidence supporting available locoregional treatment options for intermediate-stage HCC.

Radiofrequency Ablation Combined With Transarterial Chemoembolization for Specially Located Small Hepatocellular Carcinoma

OBJECTIVE

To investigate the safety and efficacy of radiofrequency ablation combined with transarterial chemoembolization in patients with specially located small hepatocellular carcinoma.

MATERIALS AND METHODS

Between March 2014 and March 2017, a total of 26 patients with 26 lesions (10 perivascular, 6 subdiaphragmatic, 5 subcapsular, 5 perivascular, and subdiaphragmatic location; mean diameter 2.12 (0.62) cm), who received radiofrequency ablation-transarterial chemoembolization treatment, were retrospectively analyzed. Local tumor response was assessed by computed tomography/magnetic resonance imaging 1 month after the procedure. Tumor-free survival was also assessed according to the modified Response Evaluation Criteria in Solid Tumors. Complications were evaluated according to the National Cancer Institute's Common Terminology Criteria for Adverse Events (version 4.0).

RESULTS

Complete response was achieved in all patients 1 month after the procedure. During a median follow-up duration of 16.76 months (95% confidence interval: 7.78-25.73 months), local tumor recurrence occurred in 2 patients and new intrahepatic lesions developed in 7 patients. The 1-, 2-, and 3-year cumulative local tumor progression rates were 3.84%, 7.69%, and 7.69%, respectively. The median tumor-free survival duration was 21.96 months (95% confidence interval: 17.58-26.34 months). The 1-, 2-, and 3-year tumor-free survival rates were 67.4%, 46.1%, and 39.3%, respectively.

CONCLUSION

The radiofrequency ablation-transarterial chemoembolization combination therapy appears to be safe and effective and might be a treatment option for specially located small hepatocellular carcinoma lesions that have a risk of incomplete ablation or major complications.

Iodized Oil Transarterial Chemoembolization and Radiofrequency Ablation for Small Periportal Hepatocellular Carcinoma: Comparison with Nonperiportal Hepatocellular Carcinoma

PURPOSE

This study aims to evaluate the treatment outcomes of iodized oil transarterial chemoembolization (TACE) and subsequent radiofrequency ablation (RFA) for small (≤3 cm) periportal hepatocellular carcinoma (HCC) compared with nonperiportal HCC.

METHODS

Twenty-three patients [periportal group (PG); mean age, 59.8 years; 22 men, 1 woman] with periportal HCC (in contact with the portal vein >3 mm in diameter) and 279 patients [nonperiportal group (NPG); mean age, 59.1 years; 234 men, 45 women] with nonperiportal HCC were treated between March 2010 and January 2014. All cases were contraindicated for ultrasound-guided RFA or resection. Mean tumor size was 1.2 cm in each group. The baseline characteristics were not different between the groups, except for alpha-fetoprotein level (41.0 ng/dL in NPG vs. 8.8 ng/dL in PG, p = 0.001). Local tumor progression (LTP), disease-free survival (DFS), overall survival (OS), intrasegmental recurrence, and complications were analyzed using the Kaplan-Meier method and Fisher's exact test.

RESULTS

TACE and RFA were successfully performed in all patients. Mean follow-up period of PG and NPG was 33.8 and 42.8 months, respectively. LTP (p = 0.701), DFS (p = 0.718), and OS (p = 0.359) were not different between the two groups. Intrasegmental recurrence occurred in two patients (one in each group), and its incidence was not different (p = 0.212). Complications requiring further treatment occurred in 1/23 (4.3%) in PG and 5/279 (1.8%) in NPG. No procedure-related mortality occurred.

CONCLUSIONS

Iodized oil TACE and subsequent RFA are effective alternative treatments for small periportal HCC (≤3 cm) when percutaneous ultrasound- or CT-guided RFA or resection is not feasible.

Enhanced efficacy of radiofrequency ablation for hepatocellular carcinoma using a novel vascular disrupting agent, CKD-516

BACKGROUND

CKD-516 is a novel vascular disrupting agent that shuts down intratumoral blood flow. We therefore hypothesized that concomitant administration of CKD-516 would enhance the therapeutic efficacy of radiofrequency ablation (RFA) by reducing heat sink effects. We assessed the effects of the combination of CKD-516 and RFA in a rat orthotopic hepatocellular carcinoma (HCC) model.

METHODS

Rat HCC cells (N1-S1) were engrafted into the hepatic lobe of Sprague-Dawley (SD) rats. Mice were randomly divided into two groups: RFA-only and CKD-RFA. In the CKD-RFA group, CKD-516 was administered by intraperitoneal injection 2 h before RFA. Ablation zone size was measured on triphenyltetrazolium chloride-stained specimens. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed to evaluate the area of apoptosis/necrosis in the ablation zone. Immunohistochemistry with anti-CD31 antibody was performed to evaluate the effect of CKD-516 on tumor vessels.

RESULTS

Ablation zone size was significantly larger in the CKD-RFA group than in the RFA-only group (243.10 ± 74.39 versus 123.30 ± 28.17 mm², p < 0.001). On TUNEL staining, the area of apoptosis/necrosis was also significantly larger in the CKD-RFA group than in the RFA-only group (274.44 ± 140.78 versus 143.74 ± 90.13 mm²; p = 0.006). Immunohistochemistry with anti-CD31 antibody revealed patent tumor vessels in the RFA-only group, while collapsed vessels were seen in the CKD-RFA group, indicating a vascular shutdown effect of CKD-516.

CONCLUSION

Concomitant administration of CKD-516 during RFA can increase the ablation zone of tumors due to its vascular disrupting effect.

Predisposing factors for hepatocellular carcinoma recurrence following initial remission after transcatheter arterial chemoembolization

Hepatocellular carcinoma (HCC) is prone to recurrence following curative treatment. The purpose of the present study was to identify the predisposing factors of HCC recurrence following complete remission achieved by transarterial chemoembolization (TACE). A retrospective cohort study of 70 consecutive patients with HCC who underwent TACE as the initial treatment was conducted. The patients were divided into two groups according to their 1-year disease-free survival (DFS) status; the early recurrence group (ER group; n=32), with HCC recurring within 1 year of initial TACE; and the non-early recurrence group (NER group; n=38), who did not experience recurrence within 1 year. The parameters identified as significantly associated with DFS time on univariate analysis were aspartate aminotransferase (AST), alanine aminotransferase and α-fetoprotein levels, as well as the tumor number (P=0.003, P=0.027, P=0.002 and P=0.005, respectively). Multivariate analysis revealed that AST levels and tumor number were significantly associated with a shorter DFS period (P=0.009 and P=0.038, respectively). The Mantel-Haenszel test revealed a significant trend of decreasing DFS with increasing tumor number. Among the patients with HCC in the ER group, locoregional recurrence occurred more frequently in those who received TACE alone compared with those treated with TACE combined with radiofrequency ablation treatment. In summary, multinodularity of HCC is the most potent predictive factor for the recurrence of HCC within 1 year of initial TACE.

Clinical utility of radiofrequency ablation following transarterial injection of miriplatin-iodized oil suspension in small hepatocellular carcinoma

PURPOSE

To retrospectively evaluate the clinical utility of radiofrequency ablation (RFA) following transarterial injection of miriplatin-iodized oil suspension (MPT-RFA) for hepatocellular carcinoma treatment.

MATERIALS AND METHODS

We evaluated clinical outcomes of MPT-RFA for three or fewer hepatocellular carcinomas. Twenty-one patients with 30 tumors (maximum diameter: mean 1.4 ± 0.4 cm, range 0.7-2.2 cm) received MPT-RFA.

RESULTS

Nineteen patients (90.5 %, 19/21) achieved complete ablation at the first RFA session. Two patients (9.5 %, 2/21) required a second RFA session but achieved complete ablation. Primary and secondary technical success rates were 90.5 and 100 %. There were no deaths related to the procedures performed. Grade 3 or 4 increases in the serum aspartate aminotransferase, alanine aminotransferase, and bilirubin levels were found in six patients (38.1 %, 8/21). There were no liver infarctions. During the median follow-up period of 24.1 months (mean ± SD 24.7 ± 6.9 months, range 13.8-38.9 months), the local tumor progression rate and overall survival rate at 2 years was 5.0 % (95 % confidence interval 0.3-20.6 %) and 86.7 % (95 % confidence interval 56.3-96.5 %), respectively. The mean hospital stay was 8.4 ± 3.1 days (range 5-18 days).

CONCLUSION

MPT-RFA is a safe therapeutic option that initially provides therapeutic results.

Treatment of Small Hepatocellular Carcinoma (≤2 cm) in the Caudate Lobe with Sequential Transcatheter Arterial Chemoembolization and Radiofrequency Ablation

PURPOSE

To evaluate technical feasibility and treatment results of sequential transcatheter arterial chemoembolization (TACE) and cone-beam computed tomography-guided percutaneous radiofrequency ablation (CBCT-RFA) for small hepatocellular carcinoma (HCC) in the caudate lobe.

MATERIALS AND METHODS

Institutional review board approved this retrospective study. Radiologic database was searched for the patients referred to perform TACE and CBCT-RFA for small caudate HCCs (≤2 cm) between February 2009 and February 2014. A total of 14 patients (12 men and 2 women, mean age; 61.3 years) were included. Percutaneous ultrasonography-guided RFA (pUS-RFA) and surgery were infeasible due to poor conspicuity, inconspicuity or no safe electrode pathway, and poor hepatic reserve. Procedural success (completion of both TACE and CBCT-RFA), technique efficacy (absence of tumor enhancement at 1 month after treatment), and complication were evaluated. Treatment results including local tumor progression (LTP), intrahepatic distant recurrence (IDR), overall survival (OS), and progression-free survival (PFS) were analyzed.

RESULTS

Procedural success and technique efficacy rates were 78.6 % (11/14) and 90.9 % (10/11), respectively. Average follow-up period was 45.3 months (range, 13.4-64.6 months). The 1-, 3-, and 5-year LTP probabilities were 0, 12.5, and 12.5 %, respectively. IDR occurred in seven patients (63.6 %, 7/11). The 1-, 3-, and 5-year PFS probabilities were 81.8, 51.9, and 26 %, respectively. The 1-, 3-, and 5-year OS probabilities were 100, 80.8, and 80.8 %, respectively.

CONCLUSION

Combination of TACE and CBCT-RFA seems feasible for small HCC in the caudate lobe not amenable to pUS-RFA and effective in local tumor control.

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.

Combination of percutaneous radiofrequency ablation with transarterial chemoembolization for hepatocellular carcinoma: observation of clinical effects

OBJECTIVE

To observe the clinical effect of radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) for advanced hepatocellular carcinoma (HCC).

METHODS

A total of 92 cases of advanced primary liver cancer underwent TACE and RFA treatment from June 2005 to 2011 at the Department of Hepatobiliary Surgery, the First Affiliated Hospital of Bengbu Medical College. A total of 88 cases with complete clinical treatment and follow-up data were divided into two groups: 43 patients treated with TACE (TACE group) and 45 patients that received TACE combined with RFA treatment (TACE + RFA group). After clinical data assessment, tumor size and survival status were not significantly different between the groups as determined by stratified analysis.

RESULTS

Before and after surgery, spiral CT radiography and color comparison observed ablation conditions. The tumor necrosis rates after treatment (CR + PR) were 67.4% (29/43) and 91.1% (41/45) for the TACE and combined treatment groups, respectively, and the difference was statistically significant (P<0.05). The quality of life was significantly improved for patients undergoing TACE + RFA compared with the control group. Survival duration was not significantly different in patients undergoing TACE + RFA compared with the control group.

CONCLUSIONS

In this study, the effect of RFA combined with TACE treatment was better than TACE alone in treating advanced HCC.

CT-guided irreversible electroporation in an acute porcine liver model: effect of previous transarterial iodized oil tissue marking on technical parameters, 3D computed tomographic rendering of the electroporation zone, and histopathology

PURPOSE

To evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.

METHODS

After Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann-Whitney test. Histopathological differences were assessed.

RESULTS

Mean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm(3), and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm(3), and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.

CONCLUSION

There is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

Colorectal cancer metastasis: the DNA repair inhibitor Dbait increases sensitivity to hyperthermia and improves efficacy of radiofrequency ablation

PURPOSE

To assess the usefulness of combining hyperthermia with a DNA repair inhibitor (double-strand break bait [Dbait]) and its potential application to radiofrequency ablation (RFA) in a preclinical model of human colorectal cancer.

MATERIALS AND METHODS

The local ethics committee of animal experimentation approved all investigations. First, the relevance was assessed by studying the survival of four human colorectal adenocarcinoma cell cultures after 1 hour of hyperthermia at 41°C or 43°C with or without Dbait. Human colon adenocarcinoma cells (HT-29) were grafted subcutaneously into nude mice (n = 111). When tumors reached approximately 500 mm(3), mice were treated with Dbait alone (n = 20), sublethal RFA (n = 21), three different Dbait schemes and sublethal RFA (n = 52), or a sham treatment (n = 18). RFA was performed to ablate the tumor center alone. To elucidate antitumor mechanisms, 39 mice were sacrificed for blinded pathologic analysis, including assessment of DNA damage, cell proliferation, and tumor necrosis. Others were monitored for tumor growth and survival. Analyses of variance and log-rank tests were used to evaluate differences.

RESULTS

When associated with mild hyperthermia, Dbait induced cytotoxicity in all tested colon cancer cell lines. Sublethal RFA or Dbait treatment alone moderately improved survival (median, 40 days vs 28 days for control; P = .0005) but combination treatment significantly improved survival (median, 84 days vs 40 days for RFA alone, P = .0004), with approximately half of the animals showing complete tumor responses. Pathologic studies showed that the Dbait and RFA combination strongly enhances DNA damage and coagulation areas in tumors.

CONCLUSION

Combining Dbait with RFA sensitizes the tumor periphery to mild hyperthermia and increases RFA antitumor efficacy.

Heat shock protein 70 expression and effect of combined transcatheter arterial embolization and radiofrequency ablation in the rabbit VX2 liver tumour model

AIM

To evaluate the effects of a combined therapy using transcatheter arterial embolization (TAE) and radiofrequency ablation (RFA) on heat shock protein 70 (HSP70) expression and treatment effects in a rabbit model of VX2 liver tumours.

MATERIALS AND METHODS

Tumour growth and necrosis rates were evaluated on day 7. Five rabbits were assigned to each group and were killed on days 1, 3, and 7 after treatment. HSP70 expression was detected and quantified by immunohistochemistry, Western blot, and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Tumour growth rate was significantly decreased and the necrosis rate increased in the TAE + RFA group on day 7 compared with the other groups. HSP70 expression in the TAE group peaked on day 1 and bottomed on days 3 and 7. HSP70 expression in the TAE group was significantly greater than in the control group on days 1, 3, and 7. HSP70 expression was increased on day 1, peaked on day 3, and dropped on day 7 in the RFA and TAE + RFA groups. In the TAE + RFA group, HSP70 expression was significantly greater than in the other groups on days 1, 3, and 7. HSP70 expression in Western blot analysis and HSP70 mRNA peaked on day 3 and dropped on day 7 in the TAE, RFA, and TAE + RFA groups.

CONCLUSIONS

HSP70 over-expression in residual tumours after TAE + RFA could be attributed to the additive effects of hypoxia and hyperpyrexia generated by TAE combined with RFA.

Comparison of internally cooled wet electrode and hepatic vascular inflow occlusion method for hepatic radiofrequency ablation

Background/Aims

Various strategies to expand the ablation zone have been attempted using hepatic radiofrequency ablation (RFA). The optimal strategy, however, is unknown. We compared hepatic RFA with an internally cooled wet (ICW) electrode and vascular inflow occlusion.

Methods

Eight dogs were assigned to one of three groups: only RFA using an internally cooled electrode (group A), RFA using an ICW electrode (group B), and RFA using an internally cooled electrode with the Pringle maneuver (group C). The ablation zone diameters were measured on the gross specimens, and the volume of the ablation zone was calculated.

Results

The ablation zone volume was greatest in group B (1.82±1.23 cm³), followed by group C (1.22±0.47 cm³), and then group A (0.48±0.33 cm³). The volumes for group B were significantly larger than the volumes for group A (p=0.030). There was no significant difference in the volumes between groups A and C (p=0.079) and between groups B and C (p=0.827).

Conclusions

Both the usage of an ICW electrode and hepatic vascular occlusion effectively expanded the ablation zone. The use of an ICW electrode induced a larger ablation zone with easy handling compared with using hepatic vascular occlusion, although this difference was not statistically significant.

Superselective particle embolization enhances efficacy of radiofrequency ablation: effects of particle size and sequence of action

PURPOSE

To evaluate the effects of particle size and course of action of superselective bland transcatheter arterial embolization (TAE) on the efficacy of radiofrequency ablation (RFA).

METHODS

Twenty pigs were divided into five groups: group 1a, 40-μm bland TAE before RFA; group 1b, 40-μm bland TAE after RFA; group 2a, 250-μm bland TAE before RFA; group 2b, 250-μm bland TAE after RFA and group 3, RFA alone. A total of 40 treatments were performed with a combined CT and angiography system. The sizes of the treated zones were measured from contrast-enhanced CTs on days 1 and 28. Animals were humanely killed, and the treated zones were examined pathologically.

RESULTS

There were no complications during procedures and follow-up. The short-axis diameter of the ablation zone in group 1a (mean ± standard deviation, 3.19 ± 0.39 cm) was significantly larger than in group 1b (2.44 ± 0.52 cm; P = 0.021), group 2a (2.51 ± 0.32 cm; P = 0.048), group 2b (2.19 ± 0.44 cm; P = 0.02), and group 3 (1.91 ± 0.55 cm; P < 0.001). The greatest volume of ablation was achieved by performing embolization with 40-μm particles before RFA (group 1a; 20.97 ± 9.65 cm(3)). At histology, 40-μm microspheres were observed to occlude smaller and more distal arteries than 250-μm microspheres.

CONCLUSION

Bland TAE is more effective before RFA than postablation embolization. The use of very small 40-μm microspheres enhances the efficacy of RFA more than the use of larger particles.

Ablative zone size created by radiofrequency ablation with and without chemoembolization in small hepatocellular carcinomas

PURPOSE

We retrospectively evaluated whether combined use of chemoembolization expands ablative zone sizes created by radiofrequency (RF) ablation in patients with small hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

Fifty-seven patients treated with single RF ablation for solitary HCC measuring ≤2 cm were assessed. RF ablation alone was done in nine patients and in 48 patients following chemoembolization, with an interval of 0 days in 6, 1-14 days in 27, 15-28 days in 6, and ≥4 weeks in 9. Ablative zone sizes, disappearance of tumor enhancement, and creation of sufficient ablative margins (>5 mm) were evaluated on contrast-enhanced computed tomography (CT) images.

RESULTS

Both mean long-axis (4.2-4.7 vs. 3.6 ± 0.4 cm, p < 0.04) and short-axis (3.3-3.8 vs. 2.3 ± 0.5 cm, p < 0.03) diameters were expanded significantly when RF ablation was done until 4 weeks after chemoembolization than with RF ablation alone. Tumor enhancement disappeared in all patients. Frequency of achieving sufficient ablative margins was significantly higher when RF ablation was done until 4 weeks after chemoembolization than with RF ablation alone (74.0-83.3 vs. 22.2 %, p < 0.05).

CONCLUSION

Ablative zones created by RF ablation with chemoembolization become larger than RF ablation alone, leading to secure ablative margins.

Microwave coagulation using a perfusion microwave electrode: Preliminary experimental study using ex vivo and in vivo liver

To assess the coagulation capability of a perfusion microwave electrode (PME) as a key component of microwave coagulation therapy, a preliminary experimental study was performed using ex vivo and in vivo livers. For a microwave electrode, a PME was employed. Using a PME, saline was passed through the electrode and injected continuously into the target tissue. Using an ex vivo bovine liver, the range of tissue coagulation was measured for various volumes of infused saline and microwave outputs. Using an in vivo porcine liver, the efficiency of coagulation by a PME was compared with that of radiofrequency ablation (RFA) using a cool-tip needle. In an ex vivo bovine liver, the range of tissue coagulation increased as the flow rate of saline increased. In the in vivo porcine liver, the range of coagulation was similar to that found in the ex vivo bovine liver. With a PME under conditions of a microwave output of 80 W, a flow rate of 3 ml/min and irradiation time of 5 min, the range of coagulation was 44.8±2.8 mm [maximum vertical diameter: (a)] x 31.2±2.4 mm [maximum transverse diameter: (b)]. The range of RFA (cool-tip needle) at 12 min was 46.0±2.0 mm (a) x 30.2±2.0 mm (b). With only 5 min of microwave irradiation, the use of a PME enabled induction of the same range of coagulation that was obtainable by RFA for 12 min. In comparison with microwave coagulation without saline infusion, the use of a PME made it possible to extend the range of tissue coagulation to a range equal to that of RFA in a short time. Microwave coagulation using a PME may be one of the suitable tissue coagulation systems for local ablation treatment.

Effect of interval between transcatheter hepatic arterial embolization and radiofrequency ablation on ablated lesion size in a swine model

PURPOSE

The aim of the study was to clarify the effect of the interval between transcatheter hepatic arterial embolization (TAE) with Lipiodol plus gelatin sponge particles and radiofrequency (RF) ablation on the extent of ablation.

MATERIALS AND METHODS

Eight healthy swine were divided into four groups: RF ablation (ablation only), RF ablation immediately after TAE (immediate ablation), RF ablation 3 days after TAE (3-day ablation), and RF ablation 6 days after TAE (6-day ablation). Five ablated lesions were created in each swine (10 per group). A 2-cm expandable LeVeen needle electrode was used for RF ablation. Ablated lesions are composed of an outer reddish zone and an inner whitish zone.

RESULTS

The average longest length of the major, intermediate, and minor axes and the volume in the immediate ablation, 3-day ablation, and 6-day ablation groups were significant longer and greater (1.52 and 1.52, 1.46 and 1.50, and 1.37 and 1.35 times greater in the red zone and the whitish area, respectively) than those in the ablation-only group (P < 0.05/3). Accumulation of Lipiodol was still noted in the hepatic sinusoids in the 3-day and 6-day ablation groups.

CONCLUSION

RF ablation delayed to 6 days following TAE produced larger ablation volumes than did RF ablation alone.

Emerging local ablation techniques

Local ablation technologies for hepatic malignancy have developed rapidly in the past decade, with advances in several percutaneous or externally delivered treatment methods including radiofrequency ablation, microwave ablation, laser ablation, and high-intensity focused ultrasound. Research has focused on increasing the size of the ablation zone and minimizing heat-sink effects. More recent developments include improvements in treatment planning and navigation with integration of several imaging modalities, as well as automated delivery of the ablation through robotics. These improvements will allow increased consistency in treatment delivery and will facilitate translation to the community setting. Combination therapies with multimodality guidance are on the cutting edge of image-guided, minimally invasive cancer therapies. Local ablation is being combined with regional therapies, such as arterial chemoembolization and local activation of systemically administered drugs, with promising results. Potential combinations with local ablation also include external radiation therapy and antitumor immune modulation. Image-guided oncology is emerging as an important part of the interventional radiology practice, thanks in part to the innovation and imaging background that lies at the roots of our discipline.

Radiofrequency ablation of the liver: extended effect of transcatheter arterial embolization with iodized oil and gelatin sponge on histopathologic changes during follow-up in a pig model

PURPOSE

To assess the extended effects of transcatheter arterial embolization with iodized oil and gelatin sponge on liver histopathologic changes in radiofrequency (RF)-ablated zones and the surrounding liver parenchyma in a pig model.

MATERIALS AND METHODS

Eighteen consecutive pigs subjected to 36 RF applications performed immediately after segmental embolization with iodized oil and gelatin sponge to the left lobe of the liver (embolization/RF ablation) were euthanized immediately after the procedure or 1 or 4 weeks later. The right lobes were used as controls for RF applications without embolization. The ablated zones and the surrounding liver parenchyma were measured and examined histopathologically.

RESULTS

The average maximum ablated zone was significantly larger in the embolization/RF ablation specimens than in the RF ablation-alone specimens at all three follow-up time points. Ten of the 12 specimens obtained immediately after embolization/RF ablation showed wide hemorrhagic areas spreading to the periphery of the liver and microscopically showed marked intralobular congestion with sinusoidal dilation. This hemorrhagic change had disappeared in all the specimens obtained 1 week after embolization/RF ablation, but 10 of the 12 specimens showed wedge-shaped areas of segmental degenerative parenchyma beginning at the ablated zone and extending to the periphery of the liver; these were microscopically revealed to be areas of coagulative necrosis, indicating hepatic infarction. The sizes of these necrotic zones had decreased at 4 weeks after embolization/RF ablation.

CONCLUSIONS

RF ablation performed immediately after embolization in normal pig liver induced large ablated zones accompanied by wedge-shaped areas of segmental infarction.

Imaging to optimize liver tumor ablation

Surgical resection remains the ideal treatment for hepatocellular carcinoma and metastasis to the liver. Many alternatives are available for treatment of nonsurgical candidates. Regardless of treatment, optimizing imaging in the pretreatment, treatment and post-treatment settings is critical in order to lower the rates of local tumor progression and maximize the effectiveness of treatment that may result in prolonged survival. This article summarizes some basic imaging techniques of primary and metastatic liver tumors with a focus on how to optimize their treatment with ablation.

Combination radiofrequency ablation and intravenous radiolabeled liposomal Doxorubicin: imaging and quantification of increased drug delivery to tumors

PURPOSE

To identify, with noninvasive imaging, the zone of radiopharmaceutical uptake after combination therapy with radiofrequency (RF) ablation and intravenous administration of technetium 99m ((99m)Tc) liposomal doxorubicin in a small-animal tumor model, and to quantify and correlate the uptake by using imaging and tissue counting of intratumoral doxorubicin accumulation.

MATERIALS AND METHODS

This study was approved by the animal care committee. Two phases of animal experiments were performed. In the first experiment, a single human head-and-neck squamous cell carcinoma tumor was grown in each of 10 male nude rats. Seven of these animals were treated with intravenous (99m)Tc-liposomal doxorubicin followed by RF tumor ablation at a mean temperature of 70 degrees C + or - 2 for 5 minutes, and three were treated with intravenous (99m)Tc-liposomal doxorubicin only. Combination single photon emission computed tomography-computed tomography (SPECT/CT) was performed at 15 minutes, 4 hours, and 20 hours after therapy. In the second experiment, two tumors each were grown in 11 rats, but only one of the tumors was ablated after intravenous administration of (99m)Tc-liposomal doxorubicin. SPECT/CT and planar scintigraphy were performed at the same posttreatment intervals applied in the first experiment, with additional planar imaging performed at 44 hours. After imaging, tissue counting in the excised tumors was performed. Radiotracer uptake, as determined with imaging and tissue counting, was quantified and compared. In a subset of three animals, intratumoral doxorubicin accumulation was determined with fluorimetry and correlated with the imaging and tissue-counting data.

RESULTS

At both SPECT/CT and planar scintigraphy, increased uptake of (99m)Tc-liposomal doxorubicin was visibly apparent in the ablated tumors. Results of quantitative analysis with both imaging and tissue counting confirmed significantly greater uptake in the RF ablation-treated tumors (P < .001). Intratumoral doxorubicin accumulation correlated closely with imaging (r = 0.9185-0.9871) and tissue-counting (r = 0.995) results.

CONCLUSION

Study results show that increased delivery of intravenous liposomal doxorubicin to tumors combined with RF ablation can be depicted and quantified with noninvasive imaging.

Role of sonography for implantation and sequential evaluation of a VX2 rabbit liver tumor model

OBJECTIVE

We investigated the role of sonography in the implantation process of a VX2 rabbit liver tumor model and sequential evaluation.

METHODS

Fifty rabbits were divided into 2 groups. Animals in group I underwent surgical implantation, whereas those in group II received percutaneous sonographically guided implantation. At 7, 14, 21, and 28 days after implantation, respectively, 5 rabbits in each group were examined with conventional, color Doppler (CD), contrast-enhanced (CE) pulse inversion harmonic (PIH), and CE CD sonography. Pathologic examination was performed with hematoxylin-eosin, nicotinamide adenine dinucleotide phosphate-diaphorase, and succinic dehydrogenase stains.

RESULTS

Twenty-one rabbits with tumors survived in group I, and 22 with tumors survived in group II. The mean duration of implantation +/- SD in group II was 16.9 +/- 3.4 minutes, whereas that in group I was 21.5 +/- 4.1 minutes (P < .05). The tumor volume measured by conventional sonography increased from 0.28 +/- 0.14 cm(3) at 7 days to 16.49 +/- 5.50 cm(3) at 28 days in group I and from 0.31 +/- 0.19 to 19.79 +/- 4.70 cm(3) in group II, whereas no significant difference existed between the groups. On CD, CE PIH, and CE CD sonography, most tumors were hypervascular before 14 days and after 14 days had peripheral vessels and central hypovascular areas, which were shown as necrotic areas by pathologic examination.

CONCLUSIONS

Sonographically guided implantation achieved a good success rate with convenient inoculation performance. Conventional gray scale, CD, CE PIH, and CE CD sonography were useful in sequential evaluation of tumor growth and characteristic vascularity.

Effectiveness of hepatic arterial embolization on radiofrequency ablation volume in a swine model: relationship to portal venous flow and liver parenchymal pressure

PURPOSE

To evaluate the effectiveness of transcatheter arterial embolization (TAE) on radiofrequency (RF) ablation volume and compare portal vein (PV) flow and liver parenchymal pressure before and after treatment.

MATERIALS AND METHODS

Eight healthy female swine were divided into four groups to be treated with RF ablation alone (RF-only group), RF ablation after TAE with gelatin sponge particles (GSPs; RF/TAE group), RF ablation after TAE with Lipiodol plus GSPs (RF/TAE/Lipiodol group), and PV embolization (PVE) with GSPs after TAE with Lipiodol plus GSPs (RF/TAE/Lipiodol/PVE group). Five ablations were created in each swine, with 10 ablations per group. A 2-cm expandable LeVeen needle electrode was used for RF ablation.

RESULTS

The greatest ablation volume (18,410.1 mm(3) +/- 3,986.4) was observed in the RF/TAE/Lipiodol/PVE group. Of the RF-only, RF/TAE, and RF/TAE/Lipiodol groups, the RF/TAE/Lipiodol group (14,835.5 mm(3) +/- 2,743.2) had a significantly larger ablation volume than the RF-only (8,002.6 mm(3) +/- 2,788.3) and RF/TAE groups (10,398.5 mm(3) +/- 2965.8; P < .05/3). PV pressures increased significantly after TAE (P < .01) compared with the pressure before TAE in the RF/TAE/Lipiodol and RF/TAE/Lipiodol/PVE groups, but not in the RF/TAE group. A marked increase in liver parenchymal pressure was seen during RF ablation; however, there were no significant differences among groups. Accumulation of Lipiodol was noted in the sinusoids in the RF/TAE/Lipiodol and RF/TAE/Lipiodol/PVE groups.

CONCLUSIONS

TAE with blockade of PV flow before RF ablation was associated with greater ablation volumes. Liver parenchymal pressure showed no correlation with increased ablation volume.

Optimal strategies for combining transcatheter arterial chemoembolization and radiofrequency ablation in rabbit VX2 hepatic tumors

PURPOSE

To determine the optimum combination strategy of transcatheter arterial chemoembolization and radiofrequency (RF) ablation in an experimentally induced hepatic tumor model.

MATERIALS AND METHODS

Twenty-five New Zealand White rabbits with VX2 carcinoma-induced hepatic tumors were randomly divided into five treatment groups, which received (i) chemoembolization followed 15 minutes later by RF ablation; (ii) RF ablation followed by chemoembolization; (iii) chemoembolization alone; (iv) RF ablation alone; and (v) bland embolization followed by RF ablation. Animals were euthanized at 48 hours to determine tumor infarction and coagulation, which were compared with analysis of variance. Representative histopathologic slides were compared.

RESULTS

Significantly larger areas of coagulation were produced by chemoembolization followed by RF ablation (22.0 cm(3) +/- 7.7) compared with RF ablation followed by chemoembolization (13.1 cm(3) +/- 3.2) and RF ablation alone (10.0 cm(3) +/- 4.5; P < .05). RF ablation followed by chemoembolization showed larger treatment areas than chemoembolization alone (25.0 cm(3) +/- 9.6 vs 12.1 cm(3) +/- 4.6; P < .001), with chemotherapeutic agent preferentially depositing around the coagulation zone. Histopathologic analysis revealed greater vascular thrombosis and necrosis and reduced islands of viable tumor cells in the chemoembolization/RF ablation group versus the groups treated with chemoembolization alone or bland embolization/RF ablation.

CONCLUSIONS

Larger treatment volumes were produced when chemoembolization was performed before RF ablation than when RF ablation preceded chemoembolization or when RF ablation or chemoembolization were performed alone. Larger treatment volumes were also produced when chemoembolization rather than bland embolization was performed before RF ablation, indicating the importance and synergy of the chemotherapeutic regimen. These results suggest that the reduction of tumor blood flow combined with the effect of hyperthermia and local chemotherapy creates the largest dimensions of treatment.

Clinical application of a combination therapy of lentinan, multi-electrode RFA and TACE in HCC

INTRODUCTION

Hepatocellular carcinoma (HCC) is one of the most common cancer-related causes of death worldwide and there is a clear need for further treatment options. In this study, we assessed the efficacy of a combination of lentinan (a fungal extract), transcatheter arterial chemoembolisation (TACE) and radiofrequency ablation (RFA) in HCC patients.

METHODS

Seventy-eight patients with HCC confirmed by pathology and iconographical checks were used in this study. A total of 136 tumours with a mean diameter of 6.5 cm were detected (standard deviation [SD]+/-0.7). Subjects were divided into four groups, receiving either TACE only, RFA only, RFA and TACE, or the combination group - receiving lentinan, RFA and TACE.

RESULTS

The tumour necrosis was significantly higher in the combination group (88.6%), compared to the TACE group (37.5%), the RFA group (47.8%) and the TACE/RFA group (60.3%; P<0.05). The tumour recurrence rate was significantly lower in the combination group (17.8%), compared to the TACE group (45.8%), the RFA group (34.7%) and the TACE/RFA group (29.0%; P<0.05). Finally, mean survival duration was significantly higher in the combination group (28.2 months; P<0.05).

CONCLUSION

Combination therapy involving lentinan, RFA and TACE was beneficial in terms of increasing mean survival duration, tumour necrosis and reducing the recurrence rate. Lentinan may therefore be of benefit to HCC patients.

Survival rates according to the Cancer of the Liver Italian Program scores of 345 hepatocellular carcinoma patients after multimodality treatments during a 10-year period in a retrospective study

BACKGROUND AND AIM

The Cancer of the Liver Italian Program (CLIP) score has been demonstrated to have superior prognostic ability in hepatocellular carcinoma (HCC) patients worldwide, but there has never been sufficient assessment of the efficacy of treatment modalities according to the CLIP score. This retrospective cohort study of HCC patients was conducted to assess the efficacy of treatment modalities according to the CLIP score.

METHODS

We compared the efficacy of hepatic resection (HR) (n = 101), radiofrequency ablation with prior transcatheter arterial chemoembolization (RFA + TACE) (n = 115), percutaneous ethanol injection with prior TACE (PEI + TACE) (n = 43), and TACE (n = 86) as a primary treatment in terms of survival among 345 patients treated at Mie University Hospital between 1995 and 2004, according to CLIP score.

RESULTS

The overall survival rates in the RFA + TACE group were significantly higher in the patients with CLIP scores of 1, 2, and 3 or more (5-year, 70.9%; 3-year, 73.7%; and 3-year, 100%, respectively), but they were not significantly different from the 5-year survival rates of the HR group with a CLIP score of 0 (83.7%). Among the patients with a CLIP score of 0, a significantly higher disease-free survival rate (5-year: 33.7%) was obtained in the HR subgroup (n = 35) than in the RFA + TACE subgroup (n = 35), both of which were followed since 2000, but morbidity (21.8%) was highest in the HR group.

CONCLUSION

RFA + TACE is concluded to be a safe treatment modality with better overall survival (5-year, > 60%) in HCC patients regardless of their CLIP score.

Radiofrequency ablation in a porcine liver model: Effects of transcatheter arterial embolization with iodized oil on ablation time, maximum output, and coagulation diameter as well as angiographic characteristics

AIM: To evaluate the effects of combined radiofrequency ablation and transcatheter arterial embolization with iodized oil on ablation time, maximum output, coagulation diameter, and portal angiography in a porcine liver model.

METHODS: Radiofrequency ablation (RFA) was applied to in vivo livers of 10 normal pigs using a 17-gauge 3.0 cm expandable LeVeen RF needle electrode with or without transcatheter arterial embolization (TAE) with iodized oil (n = 5). In each animal, 2 areas in the liver were ablated. Direct portography was performed before and after RFA. Ablation was initiated at an output of 30 W, and continued with an increase of 10 W per minute until roll-off occurred. Ablation time and maximum output until roll-off, and coagulated tissue diameter were compared between the 2 groups. Angiographic changes on portography before and after ablation were also reviewed.

RESULTS: For groups with and without TAE with iodized oil, the ablation times until roll-off were 320.6 ± 30.9 seconds and 445.1 ± 35.9 seconds, respectively, maximum outputs were 69.0 ± 7.38 W and 87.0 ± 4.83 W and maximal diameters of coagulation were 41.7 ± 3.85 mm and 33.2 ± 2.28 mm. Significant reductions of ablation time and maximum output, and significantly larger coagulation diameter were obtained with RFA following TAE with iodized oil compared to RFA alone. Portography after RFA following TAE with iodized oil revealed more occlusion of the larger portal branches than with RFA alone.

CONCLUSION: RFA following TAE with iodized oil can increase the volume of coagulation necrosis with lower output and shorter ablation time than RFA alone in normal pig liver tissue.

Lung cancer and radiofrequency ablation

Radiofrequency (RF) ablation is a recently developed technique for image-guided local destruction of selected tumors. Because the lung is a common site for cancer and usually has substantial functional reserve, RF ablation of lung cancers is an attractive option for minimally invasive treatment. The primary goal of the present review is to describe the natural history, staging systems, and conventional therapies for primary and secondary treatment of lung cancer, as well as the results of RF ablation in animal models and in humans for pulmonary applications, to clarify the appropriate role and limitations of this technology. The secondary goals are to review the principles of how RF works and to describe RF ablation techniques to familiarize interventionalists who may consider incorporating this technology into their practice and inform diagnostic radiologists of expected imaging findings and clinicians of their patients' anticipated courses and outcomes.