Microwave coagulation therapy accelerates growth of cancer in rat liver

SIB-IMRT combined with apatinib for unresectable hepatocellular carcinoma in patients with poor response to transarterial chemoembolization

BACKGROUND

Radiotherapy combined with apatinib exhibits synergistic anti-tumor effect, while the application of simultaneous integrated boost intensity modulated radiotherapy (SIB-IMRT) combined with apatinib in HCC patients is scarce. Hence, this study aimed to explore the treatment response, survival, and safety profile of the SIB-IMRT combined with apatinib in unresectable HCC (uHCC) patients.

METHODS

A total of 19 uHCC patients with deficient response to transarterial chemoembolization (TACE), who scheduled for SIB-IMRT combined with apatinib treatment were enrolled. The SIB-IMRT was applied at the following dose: 95% planning target volume (PTV) at 30-50 Gy/2-2.5 Gy/15-20f and 90% Boost of 45-72 Gy/3-4.5 Gy/15-20f at 5 times per week with cone beam computerized tomography validation. During and after radiotherapy, the apatinib was administrated orally with the initial dose of 500 mg per day.

RESULTS

The complete response, partial response, stable disease, and progressive disease rates were 31.6%, 36.8%, 21.1% and 10.5%, respectively. Consequently, the objective response rate and disease control rate were 68.4% and 89.5%, respectively. During a median follow-up duration of 9.0 months, the median progression-free survival (PFS) was 6.0 (95% confidential interval (CI): 4.9-7.1) months with 1-year PFS rate of 42.1%; the median overall survival (OS) was not reached with 1-year OS rate of 54.6%. The safety profile was acceptable with the most common adverse events including myelosuppression (42.1%), skin reaction (36.8%), and albuminuria (26.3%).

CONCLUSION

SIB-IMRT combined with apatinib exhibits a good efficacy and tolerable safety profile, which could be considered as a potential treatment choice for uHCC patients who have deficient response to TACE.

Immunological Effects of Histotripsy for Cancer Therapy

Cancer is the second leading cause of death worldwide despite major advancements in diagnosis and therapy over the past century. One of the most debilitating aspects of cancer is the burden brought on by metastatic disease. Therefore, an ideal treatment protocol would address not only debulking larger primary tumors but also circulating tumor cells and distant metastases. To address this need, the use of immune modulating therapies has become a pillar in the oncology armamentarium. A therapeutic option that has recently emerged is the use of focal ablation therapies that can destroy a tumor through various physical or mechanical mechanisms and release a cellular lysate with the potential to stimulate an immune response. Histotripsy is a non-invasive, non-ionizing, non-thermal, ultrasound guided ablation technology that has shown promise over the past decade as a debulking therapy. As histotripsy therapies have developed, the full picture of the accompanying immune response has revealed a wide range of immunogenic mechanisms that include DAMP and anti-tumor mediator release, changes in local cellular immune populations, development of a systemic immune response, and therapeutic synergism with the inclusion of checkpoint inhibitor therapies. These studies also suggest that there is an immune effect from histotripsy therapies across multiple murine tumor types that may be reproducible. Overall, the effects of histotripsy on tumors show a positive effect on immunomodulation.

Transarterial Chemoembolization Followed by Radiofrequency Ablation for Hepatocellular Carcinoma: Impact of the Time Interval between the Two Treatments on Outcome

PURPOSE

To compare the efficacy of radiofrequency (RF) ablation after transarterial chemoembolization within or beyond 30 days for medium-large or multiple recurrent hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

In this single-center retrospective study conducted from 2007 through 2015, 135 patients with a single recurrent HCC (>3 cm) or multiple (2-5 tumors) recurrent HCCs underwent transarterial chemoembolization plus RF ablation. A total of 62 patients underwent RF ablation after transarterial chemoembolization within 30 days (sequential group) and 73 patients underwent RF ablation after transarterial chemoembolization beyond 30 days (delayed group). Outcomes of interests included overall survival (OS), progression-free survival (PFS), and complete response (CR) rate.

RESULTS

The median OS and PFS were 49.8 and 38.0 months for sequential group, and 31.0 and 11.6 months for the delayed group. The sequential group experienced significantly better OS (hazard ratio [HR]: 0.517; P = .002) and PFS (HR, 0.621; P = .021). Among patients with multiple tumors or a single tumor >5 cm, the sequential group still had significantly longer OS (P = .022; P = .018, respectively) and PFS (P = 0.042; P = .036, respectively) than the delayed group, although no significant differences were observed among patients with solitary 3- to 5-cm tumors (P = .138; P = .803, respectively). The sequential group had a significantly better CR rate than the delayed group (85.4% vs. 68.5%, respectively; P = .035). Significant predictors of OS and PFS included maximum tumor size, number of tumors, and time interval between transarterial chemoembolization and RF ablation.

CONCLUSIONS

Transarterial chemoembolization plus sequential RF ablation within 30 days was more effective for recurrent HCCs than transarterial chemoembolization plus delayed RF ablation. The time interval within 30 days is required for treating large or multiple HCCs but may not be necessary for solitary medium-sized HCC.

Heat Stress and Thermal Ablation Induce Local Expression of Nerve Growth Factor Inducible (VGF) in Hepatocytes and Hepatocellular Carcinoma: Preclinical and Clinical Studies

The purposes of this study were to test the hypothesis that heat stress and hepatic thermal ablation induce nerve growth factor inducible (VGF) and to determine intrahepatic versus systemic VGF expression induced by thermal ablation in vivo and in patients. Hepatocytes and HCC cells were subjected to moderate (45°C) or physiologic (37°C) heat stress for 10 min and assessed for VGF expression at 0-72 h post-heat stress (n ≥ 3 experiments). Orthotopic N1S1 HCC-bearing rats were randomized to sham or laser thermal ablation (3 W × 90 s), and liver/serum was harvested at 0-7 days postablation for analysis of VGF expression (n ≥ 6 per group). Serum was collected from patients undergoing thermal ablation for HCC (n = 16) at baseline, 3-6, and 18-24 h postablation and analyzed for VGF expression. Data were analyzed using ordinary or repeated-measures one-way analysis of variance and post hoc pairwise comparison with Dunnett's test. Moderate heat stress induced time-dependent VGF mRNA (3- to 15-fold; p < 0.04) and protein expression and secretion (3.1- to 3.3-fold; p < 0.05). Thermal ablation induced VGF expression at the hepatic ablation margin at 1 and 3 days postablation but not remote from the ablation zone or distant intrahepatic lobe. There was no detectable serum VGF following hepatic thermal ablation in rats and no increase in serum VGF following HCC thermal ablation in patients at 3-6 and 18-24 h postablation compared to baseline (0.71- and 0.63-fold; p = 0.27 and p = 0.16, respectively). Moderate heat stress induces expression and secretion of VGF in HCC cells and hepatocytes in vitro, and thermal ablation induces local intrahepatic but not distant intrahepatic or systemic VGF expression in vivo.

Heat Stress and Hepatic Laser Thermal Ablation Induce Hepatocellular Carcinoma Growth: Role of PI3K/mTOR/AKT Signaling

Purpose To determine if heat stress and hepatic laser thermal ablation induce hepatocellular carcinoma (HCC) growth and to identify growth factors induced by heat stress. Materials and Methods Non-heat-stressed HCC cells were cocultured with HCC cells or hepatocytes that were heat stressed at 37°C (physiologic), 45°C (moderate), or 50°C (severe) for 10 minutes and proliferation monitored with bioluminescence imaging for up to 6 days after heat stress (three experiments). Rats bearing orthotopic N1S1 HCC were randomly assigned to undergo immediate sham or laser thermal (3 W for 60 or 90 seconds; hereafter, 3W×60s and 3W×90s, respectively) ablation of the median (local) or left (distant) hepatic lobe, and tumor growth was monitored with magnetic resonance imaging for up to 18 days after ablation (six or more rats per group). Experiments were repeated with rats randomly assigned to receive either the adjuvant phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibitor (NVP-BEZ235) or the vehicle control. Heat-stressed HCC cells and hepatocytes were analyzed by using microarray or quantitative real-time polymerase chain reaction analysis for growth factor expression (three or more experiments). Groups were compared by using one- or two-way analysis of variance, and post hoc pairwise comparison was performed with the Dunnett test. Results There were more non-heat-stressed HCC cells when cells were cocultured with cells subjected to moderate but not physiologic or severe heat stress (P < .001 for both). Local intrahepatic N1S1 tumors were larger at day 18 in the 3W×60s (mean, 3102 mm³ ± 463 [standard error]; P = .004) and 3W×90s (mean, 3538 mm³ ± 667; P < .001) groups than in the sham group (mean, 1363 mm³ ± 361) but not in distant intrahepatic tumors (P = .31). Adjuvant BEZ235 resulted in smaller N1S1 tumors in the BEZ235 and laser thermal ablation group than in the vehicle control and laser thermal ablation group (mean, 1731 mm³ ± 1457 vs 3844 mm³ ± 2400, P < .001). Moderate heat stress induced expression of growth factors in HCC cells and hepatocytes, including heparin-binding growth factor, fibroblast growth factor 21, and nerve growth factor (range, 2.9-66.9-fold; P < .05). Conclusion Moderate heat stress and laser thermal ablation induce hepatocellular carcinoma growth, which is prevented with adjuvant PI3K/mTOR/protein kinase B inhibition.

CT-guided percutaneous laser ablation of metastatic lung cancer: three cases report and literature review

Objective

To report the efficacy and safety of CT-guided percutaneous laser ablation (PLA) for metastatic lung tumors.

Methods

Three cases of metastatic lung cancer underwent CT-guided PLA, and we searched for previously published articles on the minimally invasive CT-guided RFA or MWA for lung tumors in recent five years.

Results

With the guidance of CT, all lesions had good prognosis under laser ablation. Case 1 suffering from severe pulmonary dysfunction and diffuse pulmonary bullae, had small pneumothorax. CT scan obtained four months following the ablation showed two lesions had complete responses and one partial response. Case 2 had successful complete response with absent lung mass, and also had a good postoperative condition without any discomfort in the two-month follow-up. Case 3 showed partial response and improved greatly after five months. 962 cases (mean age of 45.7 years, 62.2% male) of 1297 lung tumors with detailed information were identified from 27 articles. Of these cases, the minority manifested complications such as pneumothorax, hemoptysis, hemothorax, pneumonia, pain and fever.

Conclusions

Percutaneous CT-guided PLA could be a safe and promising minimally invasive treatment for patients with primary lung cancer or unresectable pulmonary metastases, especially multineedle PLA in large tumors, which still needs more large-scale prospective studies to convince this method in the future.

EUS dating with laser ablation against the caudate lobe or left liver tumors: a win-win proposition?

Endoscopic ultrasound (EUS) have been not only a diagnostic tool, but also available in interventional therapy, which often previously needed surgical approaches to achieve. The study aimed to evaluate the effectiveness and safety of EUS-guided Nd:YAG laser ablation in unresectable tumors of the caudate lobe and left liver. We discussed ten cases of the caudate lobe and left liver tumors underwent laser ablation with EUS guidance. And we also have reviewed previous publication of EUS-guided thermal ablation for liver tumors in several decade years. EUS-guided Nd:YAG laser ablation (LA) of these tumors were successfully completed in ten patients, who had favourable prognosis with no complications in two-month follow-up. Based on our early observations, this suggested that EUS-guided LA might be technically feasible in selected patients with tumors of the caudate lobe and left liver. However, the safety of this technique need to be further confirmed in the future and if possible larger, prospective trials.

Study on the effect of chemoembolization combined with microwave ablation for the treatment of hepatocellular carcinoma in rats

PURPOSE

We aimed to evaluate the combining effects of transarterial chemoembolization (TACE) and open local thermal microwave ablation in a hepatocellular carcinoma animal model.

METHODS

Tumor cubes were implanted into the liver of 30 male inbred ACI rats. Groups of 10 animals were treated at 13 days (TACE or microwave ablation) and 16 days (microwave ablation) postimplantation with combined therapy of TACE (0.1 mg mitomycin C; 0.1 mg iodized oil; 5.0 mg degradable starch microspheres) and microwave ablation (2450 Mhz; 45 s; 35 W) (study group A), TACE alone (control group B), or microwave ablation alone (control group C). At day 12 and day 25 tumor size was measured via magnetic resonance imaging and the relative growth ratio was calculated. Hepatic specimens were immunohistochemically examined for the expression of vascular endothelial growth factor (VEGF).

RESULTS

Mean growth rates were 1.34±0.19 in group A, 3.19±0.13 in group B, and 4.18±0.19 in group C. Compared with control groups B and C, tumor growth rate in group A was significantly inhibited (P < 0.01). The VEGF-antibody reaction in peritumoral tissue (staining intensity at portal triad, percent antibody reaction and staining intensity at central vein) was significantly lower in group A compared with group B (P < 0.01). No significant difference between group A and group C could be observed.

CONCLUSION

This investigation shows improved results of TACE followed by microwave ablation as treatment of hepatocellular carcinoma in a rat model, compared with single therapy regimen regarding the inhibition of growth rate and reduction of VEGF-level in peritumoral tissue.

Percutaneous laser ablation: a new contribution to unresectable high-risk metastatic retroperitoneal lesions?

BACKGROUND & AIMS

Metastasis in retroperitoneal lymph nodes is one of the signs of advanced stage or terminal stage of malignancy. We performed a trial to assess the safety and efficacy of ultrasonography (US)-guided local neodymium-doped yttrium aluminum garnet (Nd:YAG) laser ablation for metastatic lymph nodes in the retroperitoneal region.

METHODS

We evaluated 4 cases of retroperitoneal metastatic lymph nodes treated using US-guided Nd:YAG laser ablation. Additionally, we reviewed the PubMed database for articles on thermal ablation of retroperitoneal lesions until March 2016, without language limitations.

RESULTS

In our study, all lesions were nearly completely ablated with mild discomfort, including pain and fever at the 3-month follow-up. In the literature review, a total of 398 patients with 491 retroperitoneal tumors were identified, and complications after the procedure included enterovesical fistula, fecal incontinence, and hematoma.

CONCLUSIONS

Percutaneous laser ablation could be a theoretically promising approach for retroperitoneal metastatic lesions. ClinicalTrials.gov number: NCT02822053.

Magnetic resonance thermal imaging combined with SMASH navigators in the presence of motion

This study develops and tests an MR thermometry method combined with SMASH navigators in phantom experiments mimicking human liver motion with the purpose of detecting and correcting motion artifacts in thermal MR images. Experimental data were acquired on a 3T MRI scanner. Motion artifacts of mobile phantoms mimicking human liver motion were detected and corrected using the SMASH navigators and then MR temperature maps were obtained using a proton resonant frequency (PRF) shift method with complex image subtraction. Temperature acquired by MR thermal imaging was compared to that measured via thermocouples. MR thermal imaging combined with the SMASH navigator technique resulted in accurate temperature maps of the mobile phantoms compared to temperatures measured using the thermocouples. The differences between the obtained and measured temperatures varied from 8.2°C to 14.2°C and 2.2°C to 4.9°C without and with motion correction, respectively. Motion correction improved the temperature acquired by MR thermal imaging by >55%. The combination of the MR thermal imaging and SMASH navigator technique will enable monitoring and controlling heat distribution and temperature change in tissues during thermal therapies and will be a very important tool for cancer treatment in mobile organs.

PACS number: 87.57.‐s

Incomplete thermal ablation stimulates proliferation of residual renal carcinoma cells in a translational murine model

What's known on the subject? and What does the study add? Thermal ablation influences the local tissue microenvironment. Several studies have reported that residual tumour cells may exhibit a more aggressive phenotype. This study shows that incomplete CA and RFA cause an increased proliferation and decreased apptosis of residual renal tumour cells. This may be caused by stimulatory factors such as hypoxia, HSPs and inflammatory cells.

OBJECTIVE

To compare the effect of incomplete thermal ablation vs partial nephrectomy (PN) on growth stimulation and cellular survival in renal tumours.

MATERIALS AND METHODS

Renca renal tumours were transplanted under the renal capsule of mice (four to six mice/group) after which incomplete radiofrequency ablation (RFA), cryoablation (CA) or PN was performed. At several time points after treatment, presence of cell proliferation, apoptosis, hypoxic areas, inflammatory factors and the heat-shock proteins (HSPs) 70 and 90 were evaluated using immunohistochemistry.

RESULTS

At 2 h after thermal ablation residual tumour cells showed increased proliferation. This hyperproliferation was significantly stronger after RFA than CA (P < 0.05) and not present after PN. Residual cells showed increased apoptosis after 2 h and decreased apoptosis from 2 days after thermal ablation. Apoptotic cells were significantly less evident at 3 days after RFA (P < 0.001). Hypoxic areas and HSPs were increasingly present from 2 h up to 7 days after thermal ablation (P < 0.001). Inflammatory cells infiltrated mainly the necrotic areas after thermal ablation, and their abundance peaked at 1 week after ablation (P < 0.05). The increased cell growth was preceded by hypoxia and presence of HSPs.

CONCLUSIONS

CA and RFA result in an increased proliferation and decreased apoptosis of residual renal tumour cells. This hyperproliferation may be caused by stimulatory factors, e.g. hypoxia, HSPs and inflammatory cells, and could facilitate recurrences of renal tumours after thermal ablation. This study highlights the importance of achieving complete tumour destruction.

Lessons learned from 100 initial cases of laparoscopic liver surgery

PURPOSE

Laparoscopic liver resection (LLR) is now widely accepted and is being increasingly performed. The present study describes our experience with LLR at a single center over an eight-year period.

METHODS

This retrospective study enrolled 100 patients between October 2002 and February 2010. Forty-six benign lesions and 54 malignant lesions were included. The LLR performed included 58 pure laparoscopy procedures, 18 hand-assisted laparoscopy procedures and 24 hybrid technique procedures.

RESULTS

The mean age of the patients was 57 years; among these patients, 31 were over 65 years of age. The mean operation time was 220 minutes. The overall morbidity was 11% and the mortality was zero. Among the 20 patients with simple hepatic cysts, 50% unexpectedly recurred. Among the 41 patients with hepatocellular carcinoma, 21 patients (51%) underwent preoperative radiofrequency ablation therapy or transarterial chemoembolization. During parenchymal-transection, 11 received blood transfusion. The width of the resection margins was under 0.5 cm in 11 cases (27%); 0.5 to 1 cm in 22 cases (54%) and over 1 cm in eight cases (12%). There was no port site seeding, but argon beam coagulation-induced tumor dissemination was observed in two cases. The overall two-year survival rate was 75%.

CONCLUSION

This study suggests that the applications for LLR can be gradually expanded when assuring that the safety and curability of LLR are equivalent to that of open liver resection.

Changes in growth factor levels after thermal ablation in a murine model of colorectal liver metastases

OBJECTIVES

This study examines changes in the expression of growth factors following thermal ablation (TA) of selected colorectal cancer (CRC) liver metastases.

METHODS

Using mice with established CRC liver metastases, two tumours in each animal were thermally ablated. Liver and tumour tissues were collected at various time-points (days 0, 1, 2, 3, 5 and 7) following TA treatment from the ablation site and from sites distant from ablated tumour. Changes in growth factor expression (epidermal growth factor [EGF], vascular endothelial growth factor [VEGF], hepatocyte growth factor [HGF] and transforming growth factor-β[TGF-β]) in comparison with baseline levels (non-ablated) were assessed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry.

RESULTS

Baseline TGF-β and VEGF levels in the liver parenchyma of tumour-bearing mice were significantly higher than levels in naive liver parenchyma. Levels of VEGF and HGF decreased after TA treatment in all tissues. Levels of EGF decreased in ablated and distant tumour tissues, but displayed a tendency to increase in liver tissue. Levels of TGF-β also decreased during the first 2 days following TA, but later increased in liver and tumour tissues distant from the ablation site to a level that reached significance in tumour tissue at day 7 (P < 0.001). Decreases in growth factor levels were also observed in animals that underwent laparotomy without TA treatment, which indicates that these decreases were caused by the experimental procedure.

CONCLUSIONS

Tumour induces upregulation of TGF-β and VEGF in liver parenchyma. Growth factors decreased after TA, but this appears to be the result of the experimental procedure rather than the TA itself. However, TA resulted in increased levels of TGF-β, which may contribute to tumour recurrence.

CD95 is a key mediator of invasion and accelerated outgrowth of mouse colorectal liver metastases following radiofrequency ablation

BACKGROUND & AIMS

Recently, we have shown that micro-metastases, in the hypoxic transition zone surrounding lesions generated by radiofrequency ablation (RFA), display strongly accelerated outgrowth. CD95 is best known for its ability to induce apoptosis but can also promote tumorigenesis in apoptosis-resistant tumor cells. Therefore, we tested whether CD95 signaling plays a role in accelerated outgrowth of colorectal liver metastases following RFA.

METHODS

Hypoxia-induced invasion was assessed in three-dimensional EGFP-expressing C26 tumor cell cultures by confocal microscopy. CD95 localization was tested by immunofluorescence. Invasion and outgrowth of liver metastases following RFA were analyzed by post-mortem confocal microscopy and by morphometric assessment of tumor load. Neutralization of CD95L was performed by using antibody MFL4. CD95 was suppressed by lentiviral RNA interference. The role of host CD95L was assessed using gld mice.

RESULTS

Micro-metastases in the hypoxic transition zone following RFA displayed a highly invasive phenotype and increased expression of CD95 and CD95L. Hypoxia-induced tumor cell invasion in vitro increased the expression of CD95 and CD95L and induced translocation of CD95 to the invasive front. In vitro invasion, metastasis invasion, and accelerated tumor growth in the transition zone were strongly suppressed by neutralizing CD95L or by suppressing tumor cell CD95. In contrast, metastasis invasion and outgrowth were unaffected in gld mice.

CONCLUSIONS

Hypoxia causes autocrine activation of CD95 on colorectal tumor cells, thereby promoting local invasion and accelerated metastasis outgrowth in the hypoxic transition zone following RFA. Further pre-clinical work is needed to assess the role of CD95L neutralization, either alone or in combination with chemotherapy, in limiting aggressive recurrence of liver metastases following RFA.

Ultrasound-guided percutaneous cryotherapy of hepatocellular carcinoma

BACKGROUND

Reports on percutaneous cryoablation to treat patients with HCC are sparse in the medical literature. This study aimed to determine the safety and efficacy of percutaneous cryotherapy for unresectable or recurrent hepatocellular carcinoma (HCC).

METHODS

The results of 40 patients with unresectable HCC and 26 patients with recurrent HCC treated with ultrasound-guided percutaneous cryotherapy from January 2006 to June 2009 were retrospectively analyzed.

RESULTS

We used percutaneous cryotherapy to treat 76 tumors in 40 patients with unresectable and 76 tumors in 26 patients with recurrent HCC. The size of the tumors was 2.8 ± 1.7 cm (mean ± S.D.). The mean number of treatment sessions for unresectable and recurrent HCC were 1.7 and 1.4, respectively. All cryotherapy procedures were technically successful. No procedure-related death was observed. The overall complication rate was 12.1%. Patients with unresectable HCC had 1-, and 3-year overall survival rates of 81.4%, and 60.3%, while the disease-free survival rates at 1 year and 3 years were 67.6% and 20.8%, respectively. Patients with recurrent HCC had 1-, and 3-year overall survival rates of 70.2%, and 28.8%, while the disease-free survival rates at 1 year and 3 years were 53.8% and 7.7%, respectively.

CONCLUSION

Ultrasound-guided percutaneous cryotherapy was safe and efficacious in the treatment of unresectable and recurrent HCC. Further randomized trials are needed to compare the safety and efficacy of cryotherapy with other forms of percutaneous treatment so that an unbiased therapeutic strategy can be devised.

Radiofrequency ablation of colorectal liver metastases induces an inflammatory response in distant hepatic metastases but not in local accelerated outgrowth

BACKGROUND

Recently, we have shown in a murine model that radiofrequency ablation (RFA) induces accelerated outgrowth of colorectal micrometastases in the transition zone (TZ) surrounding the ablated lesion. Conversely, RFA also induces an anti-tumor T-cell response that may limit tumor growth at distant sites. Here we have evaluated whether an altered density of inflammatory cells could be observed in the perinecrotic (TZ) metastases compared to hepatic metastases in the distant reference zone (RZ).

METHODS

RFA-treated tumor-bearing mice (n = 10) were sacrificed. The inflammatory cell density (neutrophils, macrophages, CD4(+) T-cells, and CD8(+) T-cells) of tumors in the TZ (TZ tumors) was compared to that in tumors in the RZ (RZ tumors). Sham-operated, tumor-bearing mice (n = 10) were analyzed simultaneously as controls (sham-treated tumors).

RESULTS

In RFA-treated, tumor-bearing mice RZ tumors contained a significantly higher density of neutrophils and CD4(+) T-cells, but not macrophages and CD8(+) T-cells compared to sham-treated tumors. Notably, TZ tumors had a significantly lower density of neutrophils, CD4(+) T-cells, and CD8(+) T-cells, but not macrophages, when compared to RZ tumors.

CONCLUSIONS

The accelerated perinecrotic tumor outgrowth following RFA is associated with a reduced density of neutrophils and T-cells compared to distant hepatic metastases. This may have implications for local tumor recurrence following RFA.

Accelerated perinecrotic outgrowth of colorectal liver metastases following radiofrequency ablation is a hypoxia-driven phenomenon

OBJECTIVE

The aim of this study was to assess how thermal ablation of colorectal liver metastases affects the outgrowth of micrometastases in the transition zone (TZ) between ablated tissue and the unaffected reference zone (RZ) in 2 different murine models.

BACKGROUND

Thermal destruction therapies of nonresectable colorectal liver metastases, including radiofrequency ablation (RFA), can provide tumor clearance, but local recurrences are common.

METHODS

Three days after intrasplenic injection of C26 colon carcinoma cells, RFA was applied to the left liver lobe. Perinecrotic microcirculation, tissue hypoxia, hypoxia inducible factor (HIF)-1alpha and HIF-2alpha, and the outgrowth of micrometastases both in the TZ and in the RZ were evaluated over time.

RESULTS

In 2 different animal models, the outgrowth of micrometastases in the TZ following RFA was stimulated approximately 4-fold compared to tumor growth in the RZ. Accelerated tumor growth in the TZ was associated with microcirculatory disturbances, prolonged hypoxia, and stabilization of HIF-1alpha and HIF-2alpha in the tumor cells. In addition, RFA induced the formation of new hepatic vessels that sprouted from existing sinusoids and grew into the generated necrotic lesion. Surprisingly, the accelerated tumor growth was not associated with these vessels. Treatment with 17DMAG prevented HIF-1alpha and HIF-2alpha stabilization and selectively reduced tumor growth in the TZ by approximately 40% without affecting tumor growth in sham-operated mice or in the RZ of RFA-treated mice. PTK787/ZK-222584, a nonselective Vascular Endothelial Growth Factor (VEGF)-receptor inhibitor, reduced RFA-stimulated tumor growth and tumor growth in the RZ to a similar extent.

CONCLUSIONS

We conclude that RFA stimulates the outgrowth of tumor cells at the lesion periphery. Angiogenesis is not the driving force behind RFA-stimulated tumor growth, but other hypoxia/HIF-activated pathways are likely to be important.

Intrahepatic dissemination of hepatocellular carcinoma after local ablation therapy

BACKGROUND/PURPOSE

We aimed to clarify the histological features of and risk factors for intrahepatic dissemination after local ablation therapy (LAT) for hepatocellular carcinoma (HCC).

METHODS

Between April 1992 and December 2005, 192 HCC patients underwent hepatic resection at our department, among whom were 17 patients who had local recurrences after LAT. Eight of these 17 patients had intrahepatic dissemination. The clinical and histological characteristics of these 8 surgically treated patients with intrahepatic dissemination were investigated.

RESULTS

Histologically, numerous intrahepatic metastases were observed, mainly in the same section as the treated tumor, together with main or sectional portal vein tumor thrombi. Before the ablation therapy, the average tumor diameter was 2.1 cm, and 62.5% of the tumors were adjacent to the main or sectional portal vein. In terms of therapeutic factors, 25% of the patients had a prior needle biopsy and 62.5% had insufficient safety margins.

CONCLUSIONS

LAT for HCCs (even those less than 3 cm in diameter) adjacent less than 5 mm to the main or sectional portal vein possibly promotes intrahepatic dissemination.

Is percutaneous radiofrequency thermal ablation of hepatocellular carcinoma a safe procedure?

AIM

To assess the safety and efficacy of percutaneous radiofrequency thermal ablation (RFA) in the treatment of nonsurgical hepatocellular carcinoma (HCC) in daily practice.

METHODS

A total of 63 consecutive patients with HCC (solitary nodule <or=5 cm or 2 nodules <or=3 cm) and cirrhosis were treated with RFA. Majority of the patients had a compensated liver disease (73% Child A) and an early tumor stage (87% CLIP 0 or 1). Indications for treatment were primary HCC therapy (30 patients), adjuvant therapy before liver transplantation (15 patients) or palliation in the remaining 18 patients with progression of HCC despite previous antitumoral treatments. RFA was performed by a 100 kW electrical generator connected to an expandable 10-hook electrode.

RESULTS

Seventy-one lesions were treated in 80 sessions. Sixteen patients required adjuvant chemoembolization. Mean follow-up was 18+/-12 months. An objective response was achieved in 87% of patients who underwent primary/adjuvant treatment. Complete histological necrosis was found in 38% of patients who underwent liver transplantation. One, 2 and 3-year survival rates were 95, 76 and 72%, respectively in patients who underwent primary/adjuvant therapy and 82, 68 and 51%, respectively in patients who underwent palliative therapy. Major complications (hemoperitoneum, pleuritis, pneumothorax and sepsis) were observed in 6.3% of the patients. Notably, rapid neoplastic progression was observed in two patients within 2 months after a single RFA session (neoplastic portal thrombosis and plurifocal HCC in one patient and cutaneous seeding and lung metastases in another patient).

CONCLUSIONS

Majority of the HCC patients treated by percutaneous RFA can achieve local control of the tumor in HCCs less than or equal to 3 cm. As the procedure can be associated with major complications and cases of rapid neoplastic dissemination may occur, a more accurate selection of candidates to RFA treatment is advisable.

Serum cytokine levels in response to hepatic cryoablation

BACKGROUND AND OBJECTIVES

Cryogenic treatment sometimes stimulates the immune system by releasing intracellular antigens. We evaluated anti-tumor immune response by analyzing alterations in serum cytokine levels.

METHODS

Percutaneous cryosurgery was performed in 13 patients with unresectable tumors. Serum levels of interleukin (IL) -4, -6, and -10, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma were measured by enzyme-linked immunosorbent assay (ELISA). The Th1/Th2 ratio was estimated from the IFN-gamma/IL-4 ratio.

RESULTS

Levels of serum factors in the immune reaction (IR) group, in which tumor necrosis was identified not only in the treated area but also away from the treated area, were compared with those in the local effect (LE) group. Serum amyloid A (SAA), C-reactive protein (CRP), and IL-6 levels were increased in both groups after three treatments. The serum IL-10 level tended to increase with the number of treatments. Pretreatment IL-10 levels in the LE group were significantly greater than those in the IR group, and the maximum value in the LE group (59.5 +/- 13.2 pg/ml) was greater than that in the IR group (47.0 +/- 15.0 pg/ml). The TNF-alpha level was increased in the IR group. Pretreatment TNF-alpha levels and maximum levels in response to treatment were significantly greater in the IR group than in the LE group (P = 0.0313). The Th1/Th2 ratio was increased in the IR group, and the maximum ratio was significantly greater in the IR group than in the LE group.

CONCLUSION

It might be possible to evaluate the appearance of immune responses to cryosurgery by monitoring serum cytokine levels.

Percutaneous radiofrequency thermal ablation for hepatocellular carcinoma

BACKGROUND

Radiofrequency thermal ablation is the first therapeutic option in percutaneous treatment of hepatocellular carcinoma but data on its long-term efficacy and safety are not conclusive.

AIM

This study reports a prospective survey on radiofrequency thermal ablation in north-east Italy.

METHODS

Data were collected on 401 patients with hepatocellular carcinoma (males 301, mean age: 68 years) treated by radiofrequency thermal ablation in 13 centres. Indication to treatment was: single nodule not eligible for surgery in 77% of patients, 2-3 nodes in 18% and multiple lesions in 5%. Mean size was 3 cm (1-8 cm). Treatment response was assessed at 1 month by spiral computerized tomography and then with ultrasound examination and new spiral computerized tomography.

RESULTS

Complete response was obtained in 67% of patients and in 27% response was 75-99%. Complete response raised to 77% in lesions smaller than 3 cm. The morbidity rate was 34%; the mortality was 0.5%, seeding was observed in four patients. Ten patients presented an unexpected rapid disease progression.

CONCLUSION

The above data show that by radiofrequency thermal ablation, complete response can be achieved only in about two-third of the cases, clearly less than expected, and that, beyond seeding, unexpected progression can be observed.

Third Prize: Comparison of radical nephrectomy, laparoscopic microwave thermotherapy, cryotherapy, and radiofrequency ablation for destruction of experimental VX-2 renal tumors in rabbits

BACKGROUND AND PURPOSE

Currently available minimally invasive renal tumor-ablation procedures include cryotherapy, radiofrequency ablation, and microwave thermotherapy. In this study, we investigated the ability of these three approaches to destroy experimental renal tumors in rabbits. The mechanism of potential tumor metastasis was also explored.

MATERIALS AND METHODS

The VX-2 tumor line is an aggressive rabbit epidermoid tumor with a high metastatic potential. An initial experiment comparing cooled-tip microwave thermotherapy with cryotherapy and radical nephrectomy for treatment of small VX-2 tumors revealed that all microwave-treated rabbits had local recurrence and that several also had diffuse intraperitoneal carcinomatosis. In view of these results, a second experiment was performed in which 45 New Zealand White rabbits were implanted laparoscopically with VX-2 xenografts underneath the kidney capsule and divided into five groups of 9 each. The test groups were microwave thermotherapy with a 3.5-mm cooled-tip probe, microwave thermotherapy with a 3.5-mm noncooled- tip probe, radiofrequency ablation with a 1.5-mm cooled-tip probe, radiofrequency ablation with a 1.5- mm non-cooled tip probe, and cryotherapy with a 2.3-mm cryoprobe. The control groups were five rabbits that were not treated, five rabbits with tumors that had the tumor pierced with a probe but were untreated, and five rabbits that underwent nephrectomy after piercing of the tumor. Treatment was initiated 5 days after tumor implantation. One month later, all animals were euthanized and autopsied.

RESULTS

At 5 days after tumor implantation, laparoscopic inspection revealed no visible peritoneal metastases. At 1 month, in the cooled and non-cooled microwave-thermotherapy groups, carcinomatosis occurred in five and six of nine animals, respectively. In comparison, carcinomatosis was detected in two of nine animals in the cryotherapy group at autopsy. With respect to cooled and non-cooled radiofrequency ablation, carcinomatosis was observed in four of nine rabbits in each group. In the control groups, none of the animals with unpierced tumors exhibited carcinomatosis, while carcinomatosis was seen in two of the five rabbits with tumor violated by piercing and in three of the five rabbits that underwent immediate nephrectomy after piercing of the tumor.

CONCLUSION

Carcinomatosis occurred most frequently in animals treated with microwave thermotherapy, followed by radiofrequency ablation, and lastly cryoablation. The simple act of piercing a highly aggressive tumor can result in local spread. More disconcerting, and less well understood, is why certain ablative modalities appear to increase the rate of intraperitoneal spread.

Altered growth patterns of colorectal liver metastases after thermal ablation

BACKGROUND

Thermal ablation by radiofrequency or laser is used increasingly for the treatment of colorectal liver metastases. Recurrence after thermal ablation is common and occurs both locally and at distant sites. One possible cause of this recurrence may be a result of growth stimulation of micrometastases in the remaining liver. This study examined the impact of thermal ablation on growth patterns of hepatic micrometastases.

METHODS

Colorectal liver metastases were induced in male CBA-strain mice via an intrasplenic injection of a murine-derived cancer cell line. Subtotal thermal ablation of the left posterior lobe of the liver (30% of total liver volume) was performed by neodymium yttrium-aluminum-garnet laser 7 days after induction of metastases. The distribution, number, cross-sectional diameter, volume, and proliferation rate of established neoplasms were compared with controls at 21 days after tumor induction. The effect of thermal ablation of 7% of the total liver volume by laser on the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor 2 (FGF-2), transforming growth factor beta, and cellular proliferation (Ki-67 antigen) adjacent to the ablated site was assessed by immunohistochemistry in separate groups of animals at specific time points after therapy.

RESULTS

Thermal ablation did not alter the overall volume, number, size, and proliferation rate of neoplasms 21 days after laser ablation. There were no extrahepatic metastases after therapy. The number of neoplasms in the regenerated posterior lobe was equivalent to control despite subtotal ablation (29 +/- 2 vs 27 +/- 2; P = NS). A greater amount of metastases occupied the regenerated thermal-ablated lobe compared with controls (55% +/- 4% vs 29% +/- 3%; P < .04). Thermal ablation stimulated liver proliferation adjacent to the treatment site at 12 hours compared with untreated controls. Stimulation peaked at 72 hours (20% +/- 1% vs 1% +/- 1%; P < .001) and persisted to 21 days after therapy. FGF-2 and VEGF expression increased in liver tissue adjacent to the ablation site compared with baseline, peaking at 12 hours (112% +/- 2% vs 102% +/- 1%; P < .001) and 72 hours (114% +/- 2% vs 101% +/- 1%; P < .001), respectively.

CONCLUSIONS

Thermal ablation promotes the progression of micrometastases to form macroscopically detectable neoplasms in treated regenerating liver. This effect may relate to an increased expression of VEGF and FGF-2 adjacent to the treatment site.

Mechanisms of Focal Heat Destruction of Liver Tumors

BACKGROUND

Focal heat destruction has emerged as an effective treatment strategy in selected patients with malignant liver tumors. Radiofrequency ablation, interstitial laser thermotherapy, and microwave treatment are currently the most widely applied thermal ablative techniques. A major limitation of these therapies is incomplete tumor destruction and overall high recurrences. An understanding of the mechanisms of tissue injury induced by focal hyperthermia is essential to ensure more complete tumor destruction. Here, the currently available scientific literature concerning the underlying mechanisms involved in the destruction of liver tumors by focal hyperthermia is reviewed.

METHODS

Medline was searched from 1960 to 2004 for literature regarding the use of focal hyperthermia for the treatment of liver tumors. All relevant literature was searched for further references.

RESULTS

Experimental evidence suggests that focal hyperthermic injury occurs in two distinct phases. The first phase results in direct heat injury that is determined by the total thermal energy applied, tumor biology, and the tumor microenvironment. Tumors are more susceptible to heat injury than normal cells as the result of specific biological features, reduced heat dissipating ability, and lower interstitial pH. The second phase of hyperthermic injury is indirect tissue damage that produces a progression of tissue injury after the cessation of the initial heat stimulus. This progressive injury may involve a balance of several factors, including apoptosis, microvascular damage, ischemia-reperfusion injury, Kupffer cell activation, altered cytokine expression, and alterations in the immune response. Blood flow modulation and administration of thermosensitizing agents are two methods currently used to increase the extent of direct thermal injury. The processes involved in the progression of thermal injury and therapies that may potentially modulate them remain poorly understood.

CONCLUSION

Focal hyperthermia for the treatment of liver tumors involves complex mechanisms. Evidence suggests that focal hyperthermia produces both direct and indirect tissue injury by differing underlying processes. Methods to enhance the effects of treatment to achieve complete tumor destruction should focus on manipulating these processes.

The emergent role of focal liver ablation techniques in the treatment of primary and secondary liver tumours

Only 20% of patients with primary or secondary liver tumours are suitable for resection because of extrahepatic disease or the anatomical distribution of their disease. These patients could be treated by ablation of the tumour, thus preserving functioning liver. This study presents a detailed review of established and experimental ablation procedures. The relative merits of each technique will be discussed and clinical data regarding the efficacy of the techniques evaluated. A literature search from 1966 to 2003 was undertaken using Medline, Pubmed and Web of Science databases. Keywords were Hepatocellular carcinoma, liver metastases, percutaneous ethanol injection, cryotherapy, microwave coagulation therapy, radiofrequency ablation, interstitial laser photocoagulation, focused high-intensity ultrasound, hot saline injection, electrolysis and acetic acid injection. Ablative techniques offer a promising therapeutic modality to treat unresectable tumours. Large-scale randomised controlled trials are required before widespread acceptance of these techniques can occur.