Percutaneous tumor ablation tools: microwave, radiofrequency, or cryoablation--what should you use and why?

Stage IA papillary and chromophobe renal cell carcinoma: effectiveness of cryoablation and partial nephrectomy

OBJECTIVES

To evaluate the effectiveness of cryoablation compared to partial nephrectomy in patients with stage IA papillary and chromophobe renal cell carcinoma (pRCC; chRCC).

MATERIAL AND METHODS

The 2004-2016 National Cancer Database was queried for adult patients with stage IA pRCC or chRCC treated with cryoablation or partial nephrectomy. Patients receiving systemic therapy or radiotherapy, as well as those with bilateral RCC or prior malignant disease were excluded. Overall survival (OS) was assessed using Kaplan-Meier plots and Cox proportional hazard regression models. Nearest neighbor propensity matching (1:1 cryoablation:partial nephrectomy, stratified for pRCC and chRCC) was used to account for potential confounders.

RESULTS

A total of 11122 stage IA renal cell carcinoma patients were included (pRCC 8030; chRCC 3092). Cryoablation was performed in 607 (5.5%) patients, and partial nephrectomy in 10515 (94.5%) patients. A higher likelihood of cryoablation treatment was observed in older patients with non-private healthcare insurance, as well as in those with smaller diameter low-grade pRCC treated at non-academic centers in specific US geographic regions. After propensity score matching to account for confounders, there was no statistically significant difference in OS comparing cryoablation vs partial nephrectomy in patients with pRCC (HR = 1.3, 95% CI: 0.96-1.75, p = 0.09) and those with chRCC (HR = 1.38, 95% CI: 0.67-2.82, p = 0.38).

CONCLUSION

After accounting for confounders, cryoablation, and partial nephrectomy demonstrated comparable OS in patients with stage IA papillary and chromophobe RCC. Cryoablation is a reasonable treatment alternative to partial nephrectomy for these histological RCC subtypes when radiologically suspected or diagnosed after biopsy.

CRITICAL RELEVANCE STATEMENT

Cryoablation might be considered as an upfront treatment alternative to partial nephrectomy in patients with papillary and chromophobe stage IA renal cell carcinoma, as both treatment approaches yield comparable oncological outcomes.

KEY POINTS

The utilization of cryoablation for stage IA papillary and chromophobe RCC increases. In the National Cancer Database, we found specific patterns of use of cryoablation. Cryoablation and partial nephrectomy demonstrate comparable outcomes after accounting for confounders.

Clinical translation of abdominal histotripsy: a review of preclinical studies in large animal models

Histotripsy is an emerging noninvasive, non-thermal, and non-ionizing focused ultrasound (US) therapy that can be used to destroy targeted tissue. Histotripsy has evolved from early laboratory prototypes to clinical systems which have been comprehensively evaluated in the preclinical environment to ensure safe translation to human use. This review summarizes the observations and results from preclinical histotripsy studies in the liver, kidney, and pancreas. Key findings from these studies include the ability to make a clinically relevant treatment zone in each organ with maintained collagenous architecture, potentially allowing treatments in areas not currently amenable to thermal ablation. Treatments across organ capsules have proven safe, including in anticoagulated models which may expand patients eligible for treatment or eliminate the risk associated with taking patients off anti-coagulation. Treatment zones are well-defined with imaging and rapidly resorb, which may allow improved evaluation of treatment zones for residual or recurrent tumor. Understanding the effects of histotripsy in animal models will help inform physicians adopting histotripsy for human clinical use.

Improved Thermal Sensitivity Using Virtual Monochromatic Imaging Derived from Photon Counting Detector CT Data Sets: Ex Vivo Results of CT-Guided Cryoablation in Porcine Liver

PURPOSE

To investigate differences in thermal sensitivity of virtual monoenergetic imaging (VMI) series generated from photon-counting detector (PCD) CT data sets, regarding their use to improve discrimination of the ablation zone during percutaneous cryoablation.

MATERIALS AND METHODS

CT-guided cryoablation was performed using an ex vivo model of porcine liver on a PCD-CT system. The ablation zone was imaged continuously for 8 min by acquiring a CT scan every 5 s. Tissue temperature was measured using fiberoptic temperature probes placed parallel to the cryoprobe. CT-values and noise were measured at the tip of the temperature probes on each scan and on VMI series from 40 to 130 keV. Correlation of CT-values and temperature was assessed using linear regression analyses.

RESULTS

For the whole temperature range of [- 40, + 20] °C, we observed a linear correlation between CT-values and temperature in reference 70 keV images (R2 = 0.60, p < 0.001) with a thermal sensitivity of 1.4HU/°C. For the most dynamic range of [- 15, + 20] °C, the sensitivity increased to 2.4HU/°C (R2 = 0.50, p < 0.001). Using VMI reconstructions, the thermal sensitivity increased from 1.4 HU/°C at 70 keV to 1.5, 1.7 and 2.0HU/°C at 60, 50 and 40 keV, respectively (range [- 40, + 20] °C). For [- 15, + 20]°C, the thermal sensitivity increased from 2.4HU/°C at 70 keV to 2.5, 2.6 and 2.7HU/°C at 60, 50 and 40 keV, respectively. Both CT-values and noise also increased with decreasing VMI keV-levels.

CONCLUSION

During CT-guided cryoablation of porcine liver, low-keV VMI reconstructions derived from PCD-CT data sets exhibit improved thermal sensitivity being highest between + 20 and - 15 °C.

Locoregional Therapy in the Management of Intrahepatic Cholangiocarcinoma: Is There Sufficient Evidence to Guide Current Clinical Practice?

PURPOSE OF REVIEW

Intrahepatic cholangiocarcinoma (iCCA) carries a dismal prognosis and, despite increasing incidence, still lacks effective treatments. In this scenario, locoregional therapies (LRT) are gaining interest as they may be effective at local tumor control and complementary to surgical and non-surgical approaches. In this article, we will review the evolving role of LRT performed by interventional radiologists in the management of iCCA.

RECENT FINDINGS

Accumulating retrospective evidence indicates that ablative therapies and transarterial embolizations are of benefit for iCCA with unresectable disease, demonstrating promising safety profiles and prolonged or comparable survival outcomes compared to systemic therapy and surgery. Additionally, for surgical candidates, portal ± hepatic venous embolization can improve the safety of hepatectomy by inducing preoperative hypertrophy of the non-involved liver lobe. LRTs are playing an increasingly important role in the multimodal treatment of iCCA from various perspectives with reduced toxicity relative to traditional treatments. To expand the scope of applications for LRTs in this setting, future prospective randomized studies are needed to confirm their efficacy and advantage.

The Efficacy of Combined Therapy of Regorafenib with Detoxicating and Stasis Softening Chinese Herbal Spleen Tonics in Mid-/Late-Stage Hepatocellular Carcinoma

Objective

To explore the efficacy of combined therapy of Regorafenib with detoxicating and stasis softening Chinese herbal spleen tonics (DSS-splenic tonics) in mid-/late-stage hepatocellular carcinoma.

Methods

Retrospective observational data of 120 patients were obtained, 60 of which received combined therapy of DSS-splenic tonics and regorafenib. Adverse event, overall survival (OS), and time-to-progress (TTP) were analyzed. Synergistic effect of DSS-spleen tonics was found and validated in human hepatocellular carcinoma HCCLM3 cell line and xenograft mouse models.

Results

Combination of regorafenib and DSS-splenic tonics also slightly extended the TTP and OS compared with treatment of regorafenib alone, suggesting DSS-splenic tonics has synergistic effect with regorafenib. Both Regorafenib and DSS-spleen tonics exerted inhibitory effect on cell viability and invasion capability of HCCLM3 cells, and combining both could enhance the antitumor effect. At molecular level, we found that VEGF, HIF-1α, MVD, and VEGF2 were all suppressed by regorafenib and DSS-splenic tonics. These results suggest that DSS-spleen tonics function synergistically with regorafenib in HCC by enhancing the regulation of regorafenib on VEGF, MMP-2, HIF-1α, and MVD, and may diminish angiogenesis during HCC progression.

Conclusion

DSS-spleen tonics could exert synergistic antitumor effect with regorafenib via targeting VEGF.

Local and Regional Therapies for Hepatocellular Carcinoma and Future Combinations

Simple Summary

Percutaneous interventional radiological techniques offer many alternatives for treatment of Hepatocellular Carcinoma (HCC) using local anesthesia and sedation. These methods aim to destroy the malignant tumors locally without affecting the non-malignant liver. In this way, complications are kept low and patient recovery is quick. Indications depend on tumor size, type and stage, as well as patient’s condition, liver function and co-morbidities. In recent years, a lot of research has been made in combining such approaches with immune therapy, but there is still much work to be done. This manuscript tries to analyze where we stand today and explain, using a comprehensive algorithm, the treatment options for each different clinical condition.

Abstract

Background: Hepatocellular carcinoma (HCC) can be treated by local and regional methods of percutaneous interventional radiological techniques. Indications depend on tumor size, type and stage, as well as patient’s condition, liver function and co-morbidities. According to international classification systems such as Barcelona Clinic Liver Cancer (BCLC) classification, very early, early or intermediate staged tumors can be treated either with ablative methods or with transarterial chemoembolization (TACE), depending on tumor characteristics. The combination of both allows for individualized forms of treatment with the ultimate goal of improving response and survival. In recent years, a lot of research has been carried out in combining locoregional approaches with immune therapy. Although recent developments in systemic treatment, especially immunotherapy, seem quite promising and have expanded possible combined treatment options, there is still not enough evidence in their favor. The aim of this review is to provide a comprehensive up-to-date overview of all these techniques, explaining indications, contraindications, technical problems, outcomes, results and complications. Moreover, combinations of percutaneous treatment with each other or with immunotherapy and future options will be discussed. Use of all those methods as down-staging or bridging solutions until surgery or transplantation are taken into consideration will also be reviewed. Conclusion: Local and regional therapies remain a mainstay of curative and palliative treatment of patients with HCC. Currently, evidence on potential combination of the local and regional treatment options with each other as well as with other treatment modalities is growing and has the potential to further individualize HCC therapy. To identify the most suitable treatment option out of these new various options, a repeated interdisciplinary discussion of each case by the tumor board is of utmost importance.

Efficacy and safety of percutaneous cryoablation for elderly patients with small hepatocellular carcinoma: A prospective multicenter study

BACKGROUND & AIMS

Management of elderly patients with hepatocellular carcinoma (HCC) has become a major concern. Some data suggest that cryoablation improves the outcomes of elderly patients with HCC, but its efficacy and safety remain unknown. This study aimed to evaluate and compare the efficacy and safety of percutaneous cryoablation with those of radiofrequency ablation (RFA) for elderly HCC patients.

METHODS

In all, 223 patients with small HCC aged ≥70 years, treatment-naïve, without metastasis were enrolled and randomized into a cryoablation group (n = 112) or a RFA (n = 111) group from July 2015 to October 2018. The primary endpoint was local tumour progression (LTP) at 3 years after treatment. The secondary endpoints including overall survival (OS), tumour-free survival (TFS), LTP and safety were analysed for these two groups after both treatments.

RESULTS

LTP rates at 1-, 3- and 5-year were 12%, 17% and 20% for cryoablation and 17%, 18% and 21% for RFA respectively (P = .735). For lesions >3 cm in diameter, LTP rates at 1- and 3-year were 13% and 22% in cryoablation group and 22% and 42% respectively, in the RFA group (P = .039). The 1-, 3- and 5-year OS rates were 90, 75% and 62% for cryoablation and 90%, 68% and 63% for RFA respectively (P = .331). The 1-, 3- and 5-year TFS rates were 59%, 32% and 25% in the cryoablation and 59%, 28% and 20% in the RFA respectively (P = .309). Major complications occurred in 6 patients (5%) following cryoablation and 6 patients (6%) following RFA (P = .886).

CONCLUSION

Cryoablation and RFA had similar LTP in elderly patients with small HCC and this study failed to meet the primary endpoint, although for a relatively large early-stage HCC the LTP rate after cryoablation was significantly lower than that after RFA.

Periprocedural factors associated with overall patient survival following percutaneous image-guided liver tumor cryoablation

PURPOSE

To assess the impact of periprocedural factors, including adverse events, on overall patient survival following image-guided liver tumor cryoablation procedures.

METHODS

In this retrospective single-institution study, 143 patients (73 male, 70 female, ages 29-88) underwent 169 image-guided liver tumor cryoablation procedures between October 1998 and August 2014. Patient, tumor and procedural variables were recorded. The primary outcome was overall survival post-procedure (Kaplan-Meier analysis). Secondary outcomes were the impact of 15 variables on patient survival, which were assessed with multivariate cox regression and log-rank tests.

RESULTS

Mean tumor diameter was 2.5 ± 1.2 cm. 26 of 143 (18.2%) patients had primary hepatic malignancies; 117 of 143 (81.8%) had liver metastases. Survival analysis revealed survivor functions at 3, 5, 7, 10 and 12 years post-ablation of 0.54, 0.37, 0.30, 0.17 and 0.06, with mean survival time of 40.8 ± 4.9 months. Tumor size ≥4 cm (p = .018), pre-procedural platelet count <100 × 10³/μL (p = .023), and prior local radiation therapy (p = .014) were associated with worse overall patient survival. Grade 3 or higher adverse events were not associated with reduced survival (p = .49).

CONCLUSIONS

All variables associated with overall survival were patient-related and none were associated with the cryoablation procedure. Pre-procedural thrombocytopenia, larger tumor size and history of prior local radiation therapy were independent risk factors for reduced overall survival in patients undergoing hepatic cryoablation. Adverse events related to hepatic cryoablation were not associated with decreased survival.

Case Report: Antiangiogenic Therapy Plus Immune Checkpoint Inhibitors Combined With Intratumoral Cryoablation for Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is a common gastrointestinal malignancy with high incidence and poor prognosis. Common treatment methods include surgery, transcatheter arterial chemoembolization (TACE), ablation, and targeted therapy. In recent years, combination treatment with antiangiogenic therapy and immune checkpoint inhibitors has made great progress in the treatment of advanced HCC. Here, we report the case of a patient with HCC who achieved a durable benefit from anti-vascular therapy and immune checkpoint inhibitors combined with intratumoral cryoablation.

Main Body

A 38-year-old male patient initially presented with severe abdominal pain that was identified as an HCC rupture and hemorrhage by computed tomography (CT). The patient underwent emergency surgery and postoperative pathology confirmed HCC. The patient received prophylactic TACE after surgery. Unfortunately, three months after surgery, the patient developed multiple liver metastases. Subsequently, he received systemic anti-vascular therapy and immune checkpoint inhibitors combined with intratumoral cryoablation. After treatment, the patient achieved extensive tumor necrosis and the disease was effectively controlled.

Conclusions

Anti-angiogenic therapy and immune checkpoint inhibitors combined with cryoablation can induce a powerful and effective systemic anti-tumor immune response, which is worthy of further research.

Breast Cancer Cryoablation: Assessment of the Impact of Fundamental Procedural Variables in an In Vitro Human Breast Cancer Model

INTRODUCTION

Breast cancer is the most prominent form of cancer and the second leading cause of death in women behind lung cancer. The primary modes of treatment today include surgical excision (lumpectomy, mastectomy), radiation, chemoablation, anti-HER2/neu therapy, and/or hormone therapy. The severe side effects associated with these therapies suggest a minimally invasive therapy with fewer quality of life issues would be advantageous for treatment of this pervasive disease. Cryoablation has been used in the treatment of other cancers, including prostate, skin, and cervical, for decades and has been shown to be a successful minimally invasive therapeutic option. To this end, the use of cryotherapy for the treatment of breast cancer has increased over the last several years. Although successful, one of the challenges in cryoablation is management of cancer destruction in the periphery of the ice ball as the tissue within this outer margin may not experience ablative temperatures. In breast cancer, this is of concern due to the lobular nature of the tumors. As such, in this study, we investigated the level of cell death at various temperatures associated with the margin of a cryogenic lesion as well as the impact of repetitive freezing and thawing methods on overall efficacy.

METHODS

Human breast cancer cells, MCF-7, were exposed to temperatures of -5°C, -10°C, -15°C, -20°C, or -25°C for 5-minute freeze intervals in a single or repeat freeze-thaw cycle. Samples were thawed with either passive or active warming for 5 or 10 minutes. Samples were assessed at 1, 2, and 3 days post-freeze to assess cell survival and recovery. In addition, the modes of cell death associated with freezing were assessed over the initial 24-hour post-thaw recovery period.

RESULTS

Exposure of MCF-7 cells to -5°C and -10°C resulted in minimal cell death regardless of the freeze/thaw conditions. Freezing to a temperature of -25°C resulted in complete cell death 1 day post-thaw with no cell recovery in all freeze/thaw scenarios evaluated. Exposure to a single freeze event resulted in a gradual increase in cell death at -15°C and -20°C. Application of a repeat freeze-thaw cycle (dual 5-minute freeze) resulted in an increase in cell death with complete destruction at -20°C and near complete death at -15°C (day 1 survival: single -15°C freeze/thaw = 20%; repeated -15°C freeze/thaw = 4%). Analysis of thaw interval time (5 vs 10 minute) demonstrated that the shorter 5-minute thaw interval between freezes resulted in increased cell destruction. Furthermore, investigation of thaw rate (active vs passive thawing) demonstrated that active thawing resulted in increased cell survival thereby less effective ablation compared with passive thawing (eg, -15°C 5/10/5 procedure survival, passive thaw: 4% vs active thaw: 29%).

CONCLUSIONS

In summary, these in vitro findings suggest that freezing to temperatures of 25°C results in a high degree of breast cancer cell destruction. Furthermore, the data demonstrate that the application of a repeat freeze procedure with a passive 5-minute or 10-minute thaw interval between freeze cycles increases the minimal lethal temperature to the -15°C to -20°C range. The data also demonstrate that the use of an active thawing procedure between freezes reduces ablation efficacy at temperatures associated with the iceball periphery. These findings may be important to improving future clinical applications of cryoablation for the treatment of breast cancer.

Liver Tumor Ablation Procedure Duration and Estimated Patient Radiation Dose: Comparing Positron Emission Tomography/CT and CT Guidance

PURPOSE

To compare procedure duration and patient radiation dose in positron emission tomography/computed tomography (PET/CT) and CT-guided liver tumor ablation procedures.

MATERIALS AND METHODS

In this retrospective, case-control study, 275 patients underwent 368 image-guided ablation procedures to treat 537 tumors. Radiologists used PET/CT guidance for 117 procedures and CT guidance for 251 procedures. PET/CT-guided procedures were performed by one radiologist (C: P.B.S.). All 3 radiologists (A: J.G.S., B: a radiologist who is not an author on this article, and C: P.B.S.) performed CT-guided procedures. Potential confounders included patient demographics, clinical and tumor characteristics, and procedural variables.

RESULTS

The mean duration and estimated patient radiation dose of PET/CT-guided procedures performed by radiologist C were 21.5 ± 4.9 minutes longer and 0.7 ± 2.8 mSv higher than CT-guided procedures performed by all radiologists in an unadjusted comparison. Adjusting for confounding, mean duration and estimated dose of PET/CT-guided procedures performed by radiologist C were 28.3 ± 3.8 minutes longer (P < .0001) and 6.2 ± 2.9 mSv higher (P = .03) than CT-guided procedures performed by the same radiologist. Comparing CT-guided procedures performed by all 3 radiologists, adjusted mean durations and estimated patient doses of procedures by the least experienced radiologist, radiologist A, and the second most experienced radiologist, radiologist B, were 24.2 ± 5.1 (P < .0001) and 18.1 ± 8.9 (P = .04) minutes longer and 13.1 ± 3.7 (P < .001) and 14.5 ± 6.4 (P = .02) mSv higher, respectively, than procedures performed by the most experienced radiologist, radiologist C.

CONCLUSIONS

PET/CT-guided liver ablations had a slightly longer duration with slightly higher estimated patient radiation dose than similar CT-guided liver ablations. Procedure duration and patient dose do not appear to be major impediments to the emerging field of PET/CT-guided tumor ablation.

Investigation of Bladder Cancer Cell Response to Cryoablation and Adjunctive Cisplatin Based Cryo/Chemotherapy

Due to a rising annual incidence of bladder cancer, there is a growing need for development of new strategies for treatment. In 2018, the World Cancer Research Fund and other groups reported that there were ~550,000 new cases worldwide of bladder cancer. It has been further estimated that >200,000 individuals die annually from bladder cancer worldwide. Various treatment options exist. However, many if not all remain suboptimal. While the preferred chemotherapeutic options have changed in the past few years there have been few advances in the bladder cancer medical device field. Cryoablation is now being evaluated as a new option for the treatment of bladder cancer. While several studies have shown cryoablation to be promising for the treatment of bladder cancer, a lack of basic information pertaining to dosing (minimal lethal temperature) necessary to destroy bladder cancer has limited its use as a primary therapeutic option. Concerns with bladder wall perforation and other side effects have also slowed adoption.

In an effort to detail the effects of freezing on bladder cancer, two human bladder cancer cell lines, SCaBER and UMUC3, were evaluated in vitro. SCaBER, a basal subtype of muscle invasive bladder cancer, and UMUC3, an intermediate transitional cell carcinoma, are both difficult to treat but are reportedly responsive to most conventional treatments. SCaBER and UMUC3 cells were exposed to a range of freezing temperatures from −10 to −25°C and compared to non-frozen controls. The data show that a single 5 minute freeze to −10°C did not affect cell viability, whereas −15°C and −20°C results in a significant reduction in viability 1 day post freeze to <20%. These populations, however, were able to recover in culture. A complete loss of cell viability was found following a single freeze at −25°C. Application of a repeat (double) freeze resulted in complete cell death at −20°C. In addition to freezing alone, studies investigating the impact of adjunctive low dose (1 μM) cisplatin pre-treatment (30 minutes and 24 hours) in combination with freezing were conducted. The combination of 30 minute cisplatin pre-treatment and mild (−15°C) freezing resulted in complete cell death. This suggests that subclinical doses of cisplatin may be synergistically effective when combined with freezing.

In summary, these in vitro results suggest that freezing to temperatures in the range of −20 to 25°C results in a high degree of bladder cancer cell destruction. Further, the data describe a potential combinatorial chemo/cryo therapeutic strategy for the treatment of bladder cancer.

Gold-Curcumin Nanostructure in Photo-thermal Therapy on Breast Cancer Cell Line: 650 and 808 nm Diode Lasers as Light Sources

Background:

Au nanoparticles (AuNPs) exhibit very unique physiochemical and optical properties, which now are extensively studied in a range of medical diagnostic and therapeutic applications. AuNPs can be used for cancer clinical treatment with minimal invasion. On the other hand, curcumin is a polyphenol derived from turmeric which is used for medical purposes due to its anti-cancer, anti-microbial, anti-oxidant and anti-inflammatory properties. Despite these potential properties of curcumin, its usage is limited in medicine due to low solubility in water. Conjugation of curcumin to AuNPs (Au-Cur nanostructure) can be increasing its solubility. Photo-thermal therapy (PTT) is a novel kind of cancer treatment which involves two major components: laser and photo-thermoconversion agents.

Materials and Methods:

Here, diode lasers emitting 808 nm and 650 nm were utilized as light sources, and synthesized Au-Cur nanostructure was applied as a photo-thermo conversion agent. UV-vis absorbance spectroscopy and dynamic light scattering (DLS) were applied to study the maximum absorption of particles, size stability of the samples and their zeta potential. The synthesized Au-Cur nanostructure under irradiation of laser is used for PPT on 4T1 cells. The cytotoxicity activity of Au-Cur nanostructure and laser irradiation on 4T1 cells was evaluated by MTT assay.

Results:

Synthesized Au-Cur nanostructure showed λ_max at 540 nm and a mean hydrodynamic diameter of 25.8 nm. 4T1 cells were exposed to an 808 nm diode laser (1.5 W cm², 10 min) in the presence of different concentrations of Au-Cur nanostructure. Next, 4T1 cells with Au-Vur nanostructure were exposed to diode laser beam (650 nm, 1.5 W cm²) for 10 min. The results revealed that Au-Cur nanostructure under laser irradiation of 808 nm more decreased cell viability of 4T1 cells compared to laser irradiation of 650 nm.

Conclusion:

It was concluded that combining an 808-nm laser at a power density of 1.5W/cm² with Au-Cur nanostructure has a destruction effect on 4T1 breast cancer cells in vitro experiments compared to laser irradiation of 650 nm.

Veterinary Clinics: Tumor Ablation

Over the past decade, interventional oncology techniques have become integrated into the treatment plans of companion animals with cancer on a regular basis. Although procedures such as stenting are performed commonly, other less frequently utilized techniques for locoregional therapy, such as embolization and ablation, are emerging and demonstrating promise. Tumor ablation techniques are categorized into two subgroups: chemical ablation and energy-based ablation. Increased utilization of ablation will allow for the determination of specific indications and evaluation of outcomes for these techniques.

Assessment of the cryoablation margin using MRI-CT fusion imaging in hepatic malignancies

AIM

To demonstrate the feasibility of magnetic resonance imaging (MRI)-computed tomography (CT) fusion imaging for the assessment of the ablative margin after cryoablation in hepatic malignancies.

MATERIALS AND METHODS

This retrospective study analysed 35 patients with 47 liver tumours treated with CT-guided cryoablation. Fusion images of pre-ablation MRI and intraoperative CT data were created on a workstation. Minimal ablative margin (MAM) assessment was categorised into three groups: (I) MAM <0 mm (tumour protruded through the ablation zone), (II) MAM 0-5 mm, and (III) MAM ≥5 mm. Local tumour progression (LTP) was assessed during follow-up.

RESULTS

MRI-CT fusion imaging was successfully achieved in 46 (97.9%) of 47 lesions. LTP was detected in 67.4% (31/46) of cases. Twenty-four (77.4%) of 31 LTPs occurred in the subcapsular region of the liver. Using fusion images, the MAM was classified as groups I, II, and III in 18, 25, and three tumours, respectively. In group I, LTP was found in 15 (83.3%) of 18 lesions, whereas in group II, LTP was detected in 16 (64%) of 25 lesions. The cumulative LTP rate in group II was significantly lower than that in group I (p=0.012).

CONCLUSION

Pre-ablation MRI and intraoperative CT fusion imaging is feasible and useful for evaluating the MAM of cryoablation in hepatic malignancies.

Assessment of cold sink effect in postulated renal cryoablation by analyzing radiographic ice ball on computed tomography

OBJECTIVE

We analyzed CT characteristics of radiographic ice ball according to anatomical location and freezing number in renal cryoablation.

METHODS

30 patients who underwent percutaneous cryoablation for renal lesions. Computed tomography (CT) was conducted at 9 min during every freezing in order to evaluate a radiographic ice ball. Software was used to reconstruct CT images of the radiographic ice ball perpendicular to cryoprobes. For each radiographic ice ball, two types of radius were measured: (a) lateral radius from epicenter to perirenal direction and (b) medial radius from epicenter to renal sinus direction. Lateral and medial radius or diameters (lateral radius plus medial radius) during the first and second freezing were compared using paired t-test, respectively.

RESULTS

Medial radius of radiographic ice ball was significantly shorter than lateral radius (first freezing, 13.8 vs 17.0 mm, p < 0.001; second freezing, 16.0 vs 19.3 mm, p < 0.001). The diameter during the second freezing was significantly longer than that during the first freezing (35.3 vs 30.8 mm, p < 0.001).

CONCLUSION

In renal cryoablation, evaluating radiographic ice ball helps identify potential postulated cold sink effect in the central portion of kidney.

ADVANCES IN KNOWLEDGE

Radiologic information of postulated cold sink effect in the kidney may help secure sufficient safety margins.

Tumor cryoablation in combination with natural killer cells therapy and Herceptin in patients with HER2-overexpressing recurrent breast cancer

In this study, we investigated the clinical benefits of a combination of tumor cryoablation with natural killer (NK) cells therapy and Herceptin for human epidermal growth factor (HER) 2-overexpressing recurrent breast cancer. From May 2015 to May 2016, 48 patients who met the enrollment criteria were assigned to three groups (n=16): cryoablation group (group I), cryoablation-NK cells therapy group (group II) and cryoablation-NK cells therapy-Herceptin group (group III). Safety and short-term effects were evaluated. All the adverse effects were manageable and acceptable. The three-therapy combination treatment not only yielded good clinical efficacy, it also improved the quality of life; reduced levels of circulating tumor cells (CTCs); reduced carcino-embryonic antigen (CEA) and cancer antigen 15-3 (CA15-3) expression; enhanced immune function significantly. Furthermore, it can resulte in significant prolongation of progression free survival (PFS). This is the first clinical study to demonstrate the benefit of the three-therapy combination of tumor cryoablation, NK cells therapy, and Herceptin for HER2-overexpressing recurrent breast cancer.

Percutaneous Image-Guided Cryoablation of Hepatic Tumors: Single-Center Experience With Intermediate to Long-Term Outcomes

OBJECTIVE

The purpose of this article is to report our intermediate to long-term outcomes with image-guided percutaneous hepatic tumor cryoablation and to evaluate its technical success, technique efficacy, local tumor progression, and adverse event rate.

MATERIALS AND METHODS

Between 1998 and 2014, 299 hepatic tumors (243 metastases and 56 primary tumors; mean diameter, 2.5 cm; median diameter, 2.2 cm; range, 0.3-7.8 cm) in 186 patients (95 women; mean age, 60.9 years; range, 29-88 years) underwent cryoablation during 236 procedures using CT (n = 126), MRI (n = 100), or PET/CT (n = 10) guidance. Technical success, technique efficacy at 3 months, local tumor progression (mean follow-up, 2.5 years; range, 2 months to 14.6 years), and adverse event rates were calculated.

RESULTS

The technical success rate was 94.6% (279/295). The technique efficacy rate was 89.5% (231/258) and was greater for tumors smaller than 4 cm (93.4%; 213/228) than for larger tumors (60.0%; 18/30) (p < 0.0001). Local tumor progression occurred in 23.3% (60/258) of tumors and was significantly more common after the treatment of tumors 4 cm or larger (63.3%; 19/30) compared with smaller tumors (18.0%; 41/228) (p < 0.0001). Adverse events followed 33.8% (80/236) of procedures and were grade 3-5 in 10.6% (25/236) of cases. Grade 3 or greater adverse events more commonly followed the treatment of larger tumors (19.5%; 8/41) compared with smaller tumors (8.7%; 17/195) (p = 0.04).

CONCLUSION

Image-guided percutaneous cryoablation of hepatic tumors is efficacious; however, tumors smaller than 4 cm are more likely to be treated successfully and without an adverse event.

Cryoablation of cardiophrenic angle lymph node metastases: a case report

Background

Cardiophrenic angle lymph node metastases are relatively rare. Surgical resection is the main treatment for cardiophrenic angle lymph node metastasis, but it is not always possible.

Case presentation

Here, we report our initial experience with cryoablation of a cardiophrenic angle lymph node metastasis from liver cancer. As the cardiophrenic angle lymph node metastasis was located close to the heart, about 200 mL of 0.9% saline was injected into the pericardium to separate the heart from the target area. The cardiophrenic angle lymph node metastasis was successfully ablated, without any complications.

Conclusions

Cryoablation may be a suitable alternative treatment for cardiophrenic angle lymph node metastasis.

Percutaneous cryoablation for hepatocellular carcinoma

Local ablation therapy is considered as a conventional treatment option for patients with early stage hepatocellular carcinoma (HCC). Although radiofrequency (RF) ablation is widely used for HCC, the use of cryoablation has been increasing as newer and safer cryoablation systems have developed. The thermodynamic mechanism of freezing and thawing used in cryoablation is the Joule-Thomson effect. Cryoablation destroys tissue via direct tissue destruction and vascular-related injury. A few recent comparative studies have shown that percutaneous cryoablation for HCCs is comparable to percutaneous RF ablation in terms of long term therapeutic outcomes and complications. Cryoablation has several advantages over RF ablation such as well visualization of iceball, no causation of severe pain, and lack of severe damage to great vessels and gallbladder. It is important to know the advantages and disadvantages of cryoablation compared with RF ablation for improvement of therapeutic efficacy and safety.

Safety and efficacy of a China-made cryoablation device in treatment of hepatocellular carcinoma smaller than 5 cm

AIM

To assess the safety and efficacy of a China-made cryoablation device in the treatment of hepatocellular carcinoma (HCC) smaller than 5 cm.

METHODS

A total of 33 patients with HCC smaller than 5 cm were treated by cryoablation using a China-made cryoablation device under the guidance of computed tomography. Operation-associated complications within and after procedures were evaluated. The efficacy of target lesions within procedures and local recurrence rate after procedures were evaluated with imaging modalities.

RESULTS

All 37 lesions of the 33 patients were successfully treated with a China-made cryablation device. Upon the finish of procedures, complete ablation was achieved in 83.78% (31/37) of lesions, and partial ablation was achieved in 16.22% (6/37). In a median follow-up period of 10.8 mo, 32 patients remained alive and 1 was lost to follow-up. The rate of local recurrence for target lesions was 30.3% (10/33), which is equal to that achieved with imported devices.

CONCLUSION

Our findings suggest that the China-made cryoablation device is safe and effective for HCC smaller than 5 cm with the capability of destroying the whole tumor lesion.

Percutaneous image-guided cryoablation: current applications and results in the oncologic field

Percutaneous imaging-guided cryoablation (PICA) is a recently developed technique, which applies extreme hypothermia to destroy tumours under close imaging surveillance. It is minimally invasive, safe, repeatable, and does not interrupt or compromise other oncologic therapies. It presents several advantages over more established heat-based thermal ablation techniques (e.g. radiofrequency ablation; RFA) including intrinsic analgesic properties, superior monitoring capability on multi-modal imaging, ability to treat larger tumours, and preservation of tissue collagenous architecture. There has been a recent large increase in reports evaluating the utility of PICA in a wide range of patients and tumours, but systematic analysis of the literature is challenging due to the rapid pace of change and predominance of extensively heterogeneous level III studies. The precise onco-therapeutic role of PICA has not been established. This narrative review outlines the available evidence for PICA in a range of tumours. Current indications include curative therapy of small T1a renal tumours; curative/palliative therapy of small primary/secondary lung tumours where RFA is unsuitable; palliation of painful bone metastases; and urologic treatment of organ-confined prostate cancer. There is growing evidence to support its use for small hepatic tumours, and encouraging results have been obtained for breast tumours, extra-abdominal desmoid tumours, and management of higher-stage tumours and oligometastatic disease. However, the overall evidence base is weak, effectively restricting PICA to cases where standard therapy and RFA are unsuitable. As the technique and evidence continue to mature, the benefits of this emerging technique will hopefully become more widely available to cancer patients in the future.

Hepatic Tumor Ablation

Tumor ablation is a safe and effective treatment available in the multidisciplinary care of the surgical oncology patient. The role of ablation is well established in the treatment of hepatocellular carcinoma and is becoming more accepted in the treatment of various malignancies metastatic to the liver, in particular colorectal cancer. Understanding the underlying technology, achieving appropriate applicator placement, using maximum energy delivery to create margins, and performing necessary adjunctive maneuvers are all required for successful tumor ablation.

Factors Affecting Lethal Isotherms During Cryoablation Procedures

Background:

Creating appropriately-sized, lethal isotherms during cryoablation of renal tumors is critical in order to achieve sufficiently-sized zones of cell death. To ensure adequate cell death in target treatment locations, surgeons must carefully select the type, size, location, and number of probes to be used, as well as various probe operating parameters.

Objective:

The current study investigates the effects of probe type, operating pressure, and clinical method on the resulting sizes of isotherms in an in vitro gelatin model.

Method:

Using a total of four cryoprobes from two manufacturers, freeze procedures were conducted in gelatin in order to compare resulting sizes of constant temperature zones (isotherms). The effects of certain procedural parameters which are clinically adjustable were studied.

Results:

Test results show that the sizes of 0 °C,-20 °C and -40 °C isotherms created by similarly-sized probes from two different manufacturers were significantly different for nearly all comparisons made, and that size differences resulting from changing the operating pressure were not as prevalent. Furthermore, isotherm sizes created using a multiple freeze procedure (a ten minute freeze, followed by a five minute passive thaw, followed by another ten minute freeze) did not result in statistically-significant differences when compared to those created using a single freeze procedure in all cases.

Conclusion:

These results indicate that selection of the probe manufacturer and probe size may be more important for dictating the size of kill zones during cryoablation than procedural adjustments to operating pressures or freeze times.

Percutaneous cryoablation of ovarian cancer metastasis to the liver: initial experience in 13 patients

OBJECTIVE

To evaluate the feasibility, safety, and effectiveness of percutaneous cryoablation for the treatment of liver metastases from ovarian cancer.

METHODS/MATERIALS

A retrospective review was performed on 13 patients with liver metastases from ovarian cancer who underwent percutaneous cryoablation with computed tomography (CT) guidance. The tumor response was assessed by enhanced computed tomography performed before treatment, 1 month after, and every 3 months after treatment. The Functional Assessment of Cancer Therapy-General quality of life (QOL) was used to assess the patients' QOL before, 1 week, 1 month, and 3 months after cryoablation.

RESULTS

A total of 27 procedures of cryoablation were performed on these patients, and 5 patients underwent repeat procedures. Complete ablation was achieved for all lesions. Months are counted from the time of cryoablation, and the median duration of follow-up was 15 months (4-22 months). At the 1-month follow-up, the primary technique effectiveness was 100%. At the 3-month follow-up, local tumor progression was observed in 2 (7.14%) of 28 lesions. The 1-year survival from the time of cryoablation was 92.3%. Two patients died after 9 and 14 months, respectively. The QOL symptoms and functioning scales were preserved in patients alive at 3 months after cryoablation. No major complications such as cryoshock, hepatic bleeding, liver abscess, biliary fistula, and renal insufficiency were encountered.

CONCLUSIONS

Our initial experience showed that cryoablation is a safe and effective ablative therapy, providing a high rate of local tumor control in ovarian cancer liver metastases.

Locoregional Therapies for Primary and Secondary Hepatic Malignancies

Management of hepatic malignancies is a multidisciplinary task with the involvement of hepatologists, medical/surgical oncologists, transplant surgeons, and interventional radiologists. The patients should be selected for a specific targeted therapy after multidisciplinary consensus. Interventional oncology has established its role in the management of hepatic malignancies. Image-guided locoregional therapies decrease the rate of systemic toxicity without compromising tumoricidal effect.

Photothermal cancer therapy by gold-ferrite nanocomposite and near-infrared laser in animal model

Surface plasmon resonance effect of gold nanostructures makes them good candidates for photothermal therapy (PTT) application. Herein, gold-ferrite nanocomposite (GFNC) was synthesized and characterized as a photothermal agent in PTT. The aim of this study was to investigate the effect of GFNC upon laser irradiation on treatment of cancer in mice bearing melanoma cancer. Thirty mice received 1.5 × 10(6) B16/F10 cells subcutaneously. After 1 week, the mice bearing solid tumor were divided into four groups: control group (without any treatment), laser group (received laser irradiation without GFNC injection), GFNC group (only received intratumorally GFNC), and GFNC + laser group (received intratumorally GFNC upon laser irradiation). In GFNC + laser group, 200 μL of fluid, 1.3 × 10(-7) mol L(-1) gold nanoparticles, was injected intratumorally and immediately the site of tumor was exposed to continuous wave diode laser beam (808 nm, 1.6 W cm(-2)) for 15 min. All mice but four were euthanized 24 h after treatment to compare the necrotic surface area histologically by using measuring graticule. Statistical analyses revealed significant differences in necrosis extent for GFNC + laser group, compared to other groups. Four subjects (control group and GFNC + laser group, two mice each) were kept for longitudinal study. Histological analyses and tumor volume measurements of the four subjects indicated that tumor in GFNC + laser group was controlled appropriately. It was concluded that combining an 808-nm laser at a power density of 1.6 W cm(-2) with GFNC has a destruction effect in melanoma cancer cells in an animal model.

Unresected Breast Cancer: Evolution of Imaging Findings Following Cryoablation

Cryoablation has been used to treat both benign and malignant breast tumors. In all but one published case, cryoablation in breast cancer has been followed by post-procedural tumor resection. We present a case of an 85-year-old woman with two nonpalpable breast cancers treated with cryoablation with 18 months of mammographic, ultrasound and histologic follow-up.

Non-extended cryoablation could be a new strategy in lung cancer management: An experiment on green fluorescent protein-labeled Lewis lung cancer-bearing mice

Modern cryoablation has been performed in solid tumor management for more than two decades. Following the surgical spirits, it seems natural to pursue radical procedures in clinical practice, which results in unnecessary adverse effects. The attempt to use non-extended procedure made some marked achievements in practice but was criticized severely, because it was supposed to induce residual tumors, which would trigger the rapid development of cancer. Oncologists favored this procedure, however, claiming that non-extended cryoablation let lung cancer patients have higher quality of lives and longer survivals, in light of clinical observations. Therefore, this study was conducted trying to solve this controversy. In this study, fifty female C57BL/6J mice were grafted green fluorescent protein (GFP)-labeled Lewis lung cancer and randomized into two groups. The bidirectional diameters and fluorescence intensity of tumors, and the body weight of mice were recorded. Two weeks after the intervention, tumor volumes increased 20.95% in the cryoablation group, significantly different from that in the control group; the fluorescence intensity decreased 49.85% in the cryoablation group but increased 125.07% in the control group. Lung metastases could be observed in only 20% of mice in the cryosurgery group, contrasted to 64% in the control group. The non-extended lung cancer cryoablation does induce marginal tumor residuals, but will not trigger rapid tumor development. Inversely, the residual tumor cells are severely struck and the metastases are suppressed after the intervention. It could be a new strategy in lung cancer management, even for patients not in early stage.

Multicenter randomized controlled trial of percutaneous cryoablation versus radiofrequency ablation in hepatocellular carcinoma

Radiofrequency ablation (RFA) is considered a curative treatment option for hepatocellular carcinoma (HCC). Growing data have demonstrated that cryoablation represents a safe and effective alternative therapy for HCC, but no randomized controlled trial (RCT) has been reported to compare cryoablation with RFA in HCC treatment. The present study was a multicenter RCT aimed to compare the outcomes of percutaneous cryoablation with RFA for the treatment of HCC. In all, 360 patients with Child-Pugh class A or B cirrhosis and one or two HCC lesions ≤ 4 cm, treatment-naïve, without metastasis were randomly assigned to cryoablation (n = 180) or RFA (n = 180). The primary endpoints were local tumor progression at 3 years after treatment and safety. Local tumor progression rates at 1, 2, and 3 years were 3%, 7%, and 7% for cryoablation and 9%, 11%, and 11% for RFA, respectively (P = 0.043). For lesions >3 cm in diameter, the local tumor progression rate was significantly lower in the cryoablation group versus the RFA group (7.7% versus 18.2%, P = 0.041). The 1-, 3-, and 5-year overall survival rates were 97%, 67%, and 40% for cryoablation and 97%, 66%, and 38% for RFA, respectively (P = 0.747). The 1-, 3-, and 5-year tumor-free survival rates were 89%, 54%, and 35% in the cryoablation group and 84%, 50%, and 34% in the RFA group, respectively (P = 0.628). Multivariate analyses demonstrated that Child-Pugh class B and distant intrahepatic recurrence were significant negative predictors for overall survival. Major complications occurred in seven patients (3.9%) following cryoablation and in six patients (3.3%) following RFA (P = 0.776).

CONCLUSION

Cryoablation resulted in a significantly lower local tumor progression than RFA, although both cryoablation and RFA were equally safe and effective, with similar 5-year survival rates.

Advances in clinical application of cryoablation therapy for hepatocellular carcinoma and metastatic liver tumor

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Although surgical resection and liver transplantation are the curative treatments, many of HCC patients do not qualify for these curative therapies at the presentation. Thus, ablation therapies are currently important modalities in HCC treatment. Among currently available ablation therapies, cryoablation (ie, cryotherapy) is a novel local therapeutic modality. However, cryoablation has not been widely used as one of ablation therapies for HCC, because of historical concerns about risk of bleeding when cryotherapy is delivered by early generation of the argon-helium device. Nevertheless, with technological advances and increased clinical experience in the past decade, clinical application of cryoablation for HCC management has significantly increased. Accumulating data have demonstrated that cryoablation is highly effective in local tumor control with well-acceptable safety profile, and the overall survival is comparable with that of radiofrequency ablation in patients with tumors <5 cm. Compared with radiofrequency ablation and other thermal-based modalities, cryoablation has several advantages, such as the ability to produce larger and precise zones of ablation. This article systemically reviews the advances in clinical application of cryoablation therapy for HCC, including the related mechanisms and technology, clinical indications, efficacy and safety profiles, and future research directions.

A simulator for percutaneous hepatic microwave thermal ablation under ultrasound guidance

The purpose of this study was to provide a simulation therapy environment for microwave thermal ablation (MWA) under the guidance of ultrasound, and to present an inexpensive and portable simulator built on real patient-based pre-operative computed tomography (CT) data. We established an experimental simulation system for teaching MWA and present the results of a preliminary evaluation of the simulator's realism and utility for training. The system comprises physical elements of an electromagnetic tracking device and an abdominal phantom, and software elements providing three-dimensional (3D) image processing tools, real-time navigation functions and objective evaluation function module. Details of the novel aspects of this system are presented, including a portable electromagnetic tracking device, adoption of real patient-based pre-operative CT data of liver, operation simulation of MWA, and recording and playback of the operation simulation. Patients with liver cancer were selected for evaluation of the clinical application value of the experimental simulation system. A total of 50 consultant interventional radiologists and 20 specialist registrars in radiology rated the simulator's hardware reality and overall ergonomics. Results show that the simulator system we describe can be used as a training tool for MWA. It enables training with real patient cases prior to surgery, and it can provide a realistic simulation of the actual procedure.

Positron Emission Tomography (PET) in Oncology

Since its introduction in the early nineties as a promising functional imaging technique in the management of neoplastic disorders, FDG-PET, and subsequently FDG-PET/CT, has become a cornerstone in several oncologic procedures such as tumor staging and restaging, treatment efficacy assessment during or after treatment end and radiotherapy planning. Moreover, the continuous technological progress of image generation and the introduction of sophisticated software to use PET scan as a biomarker paved the way to calculate new prognostic markers such as the metabolic tumor volume (MTV) and the total amount of tumor glycolysis (TLG). FDG-PET/CT proved more sensitive than contrast-enhanced CT scan in staging of several type of lymphoma or in detecting widespread tumor dissemination in several solid cancers, such as breast, lung, colon, ovary and head and neck carcinoma. As a consequence the stage of patients was upgraded, with a change of treatment in 10%-15% of them. One of the most evident advantages of FDG-PET was its ability to detect, very early during treatment, significant changes in glucose metabolism or even complete shutoff of the neoplastic cell metabolism as a surrogate of tumor chemosensitivity assessment. This could enable clinicians to detect much earlier the effectiveness of a given antineoplastic treatment, as compared to the traditional radiological detection of tumor shrinkage, which usually takes time and occurs much later.

Percutaneous Cryoablation for Liver Cancer

Based on the primary tumor site, liver cancer can be divided into two categories: (1) primary liver cancer and (2) metastatic cancer to the liver from a distant primary site. Guided cryoablation via many imaging methods induces iceball formation and tumor necrosisand is an attractive option for treating unresectable hepatocellular carcinoma (HCC) and metastatic liver cancer. There are several advantages to using cryoablation for the treatment of liver cancer: it can be performed percutaneously, intraoperatively, and laparoscopically; iceball formation can be monitored; it has little impact on nearby large blood vessels; and it induces a cryo-immunological response in situ. Clinically, primary research has shown that percutaneous cryoablation of liver cancer is relatively safe and efficient, and it can be combined with other methods, such as radiation therapy, chemotherapy, and immunology, to control disease. Although research is preliminary, cryosurgery is fast becoming an alternative treatment method for HCC or liver tumors. Here, we review the mechanisms of liver tumor cryoablation, cryoablation program selection, clinical efficiency, and complications following treatment.

Cryoablation plus chemotherapy in colorectal cancer patients with liver metastases

Cryoablation and surgery achieve similar removal rates for some colorectal cancer (CRC) liver metastasis removal, and systemic chemotherapy is accepted as the most important approach to improving overall survival (OS) in CRC patients with liver metastases. We aimed to evaluate the potential benefit of cryoablation plus chemotherapy in CRC patients with liver metastases. We retrospectively analyze 63 patients of CRC liver metastasis. There were 32 patients in group A, who have received cryoablation plus chemotherapy, and there were 31 patients in group B, who have received chemotherapy alone. We mainly observe the 2-year survival, the quality of life (QOL), and adverse effects. Patients in group A had a higher 2-year survival rate, better OS, better QOL, and better treatment response than patients in group B. Two-year survival rates were 71.9 and 51.6%,respectively, in group A and group B. The negative conversion rates of carcinoembryonic antigen and carbohydrate antigen 19-9 (CA199) were 57.1 and 61.5%, respectively, in group A, and 22.2 and 30%, respectively, in group B. The tumor shrinkage (a tumor volume reduction of ≥ 30%) rates were 62.5 and 22.6%, respectively, in groups A and B. Performance status remained stable or improved in 16 patients (50%) in group A and eight patients (25.81%) in group B. Cryoablation in combination with chemotherapy may increase the 2-year survival rate and improve QOL in CRC patients with liver metastasis.

Image-guided percutaneous ablation of hepatic malignancies

The liver is a common site of primary and secondary malignancies, often resulting in significant morbidity and mortality. Evaluating these patients in a multidisciplinary setting allows for optimal utilization of all oncologic therapies including surgery, radiation, systemic chemotherapy, transarterial therapies, and ablation. While surgical intervention often provides the best outcomes when treating most hepatic tumors, many patients are not surgical candidates due to extensive tumor burden, underlying liver disease, or other comorbid conditions. The evolution of imaging and ablation devices has allowed for the increased utilization of percutaneous ablation as definitive and palliative treatment of primary and metastatic hepatic malignancies. Ablation induces tumor necrosis by injection of chemicals (chemical ablation) or temperature modification (thermal ablation). The goal of this review is to provide an overview of different ablation techniques commonly used for hepatic malignancies, discuss the oncologic outcomes of these interventions, and outline the current indications, contraindications, and reported complications of these therapies.

Imaging Features following Thermal Ablation of Lung Malignancies

Percutaneous image-guided thermal ablation is gaining attraction as an effective alternative to surgical resection for patients with primary and secondary malignancies of the lung. Currently, no standard follow-up imaging protocol has been established or uniformly accepted. The early identification of residual or recurrent tumor would in theory enable the practitioner to offer expeditious retreatment or alternative treatment. This review elaborates on the imaging findings following thermal ablation, both heat- and cold-based, of nonresectable pulmonary malignancies.

Percutaneous imaging-guided cryoablation of liver tumors: predicting local progression on 24-hour MRI

OBJECTIVE

The purpose of this study was to determine which MRI features observed 24 hours after technically successful percutaneous cryoablation of liver tumors predict subsequent local tumor progression and to describe the evolution of imaging findings after cryoablation.

MATERIALS AND METHODS

Thirty-nine adult patients underwent technically successful imaging-guided percutaneous cryoablation of 54 liver tumors (hepatocellular carcinoma, 8; metastases, 46). MRI features pertaining to the tumor, ablation margin, and surrounding liver 24 hours after treatment were assessed independently by two readers. Fisher exact or Wilcoxon rank sum tests (significant p values < 0.05) were used to compare imaging features in patients with and without subsequent local tumor progression. Imaging features of the ablation margin, treated tumor, and surrounding liver were evaluated on serial MRI in the following year.

RESULTS

A minimum ablation margin of 3 mm or less was observed in 11 (78.6%) of 14 tumors with and 15 of 40 (37.5%) without progression (p = 0.012). A blood vessel bridging the ablation margin was noted in 11 of 14 (78.6%) tumors with and nine of 40 (22.5%) without progression (p < 0.001). The incidence of tumor enhancement 24 hours after cryoablation was similar for tumors with (10/14, 71.4%) or without (25/40, 62.5%) local progression (p = 0.75). MRI enabled assessment of the entire cryoablation margin in 49 of 54 (90.7%) treated tumors.

CONCLUSION

MRI features at 24 hours after liver cryoablation that were predictive of local tumor progression included a minimum ablation margin less than or equal to 3 mm and a blood vessel bridging the ablation margin. Persistent tumor enhancement is common after liver cryoablation and does not predict local tumor progression.

Percutaneous cryoablation of liver metastases from breast cancer: initial experience in 17 patients

AIM

To assess the feasibility, safety, and effectiveness of percutaneous cryoablation for the treatment of liver metastases from breast cancer.

MATERIALS AND METHODS

This study included 39 liver metastases in 17 female breast cancer patients who underwent computed tomography (CT)-guided percutaneous cryoablation. The mean age of the cohort was 55 years (range 30-66 years). The tumour response was evaluated by CT performed before treatment, 1 month after treatment, and every 3 months thereafter. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30) was used to assess the patients' quality of life before, 1 week, 1 month, and 3 months after cryoablation. The primary endpoints were technique effectiveness, quality of life, and complications.

RESULTS

The technical success rate was 92% with no major complication reported. At the 1-month follow-up, the primary technique effectiveness was 87.1% (34 of 39 tumours). At the 3-months follow-up, local tumour progression was observed in six of 39 lesions (15.4%). The 1-year survival from the time of cryoablation was 70.6%. The quality of life symptoms and functioning scales were preserved in patients alive at 3 months after cryoablation. The global quality of life, mean value of "pain" and "fatigue" between 3 months after cryoablation and prior to treatment showed statistically significant differences, but no clinical significance.

CONCLUSIONS

Cryoablation is a safe and effective ablative therapy, providing a high rate of local tumour control in breast cancer liver metastases.

Photothermal ablation of pancreatic cancer cells with hybrid iron-oxide core gold-shell nanoparticles

Purpose

Photothermal ablation is a minimally invasive approach, which typically involves delivery of photothermal sensitizers to targeted tissues. The purpose of our study was to demonstrate that gold nanoparticles are phagocytosed by pancreatic cancer cells, thus permitting magnetic resonance imaging (MRI) of sensitizer delivery and photothermal ablation.

Patients and methods

Iron-oxide core/gold-shell nanoparticles (GoldMag®, 30 nm diameter; Xi’an GoldMag Biotechnology Co, Xi’an, People’s Republic of China) were used. In a 96-well plate, 3 × 10⁴ PANC-1 (human pancreatic cancer cell line) cells were placed. GoldMag (0, 25, or 50 μg/mL) was added to each well and 24 hours allowed for cellular uptake. Samples were then divided into two groups: one treated with photothermal ablation (7.9 W/cm²) for 5 minutes, the other not treated. Photothermal ablation was performed using laser system (BWF5; B&W Tek, Inc, Newark, DE, USA). Intraprocedural temperature changes were measured using a fiber optic temperature probe (FTP-LN2; Photon Control Inc, Burnaby, BC, Canada). After 24 hours, the remaining number of viable cells was counted using trypan blue staining; cell proliferation percentage was calculated based on the total number of viable cells after treatment compared with control. MRI of GoldMag uptake was performed using a 7.0T ClinScan system (Bruker BioSpin, Ettlingen, Germany).

Results

Temperature curves demonstrated that with increased GoldMag uptake, laser irradiation produced higher temperature elevations in the corresponding samples; temperature elevations of 12.89°C, 35.16°C, and 79.51°C were achieved for 0, 25, and 50 μg/mL GoldMag. Without photothermal ablation, the cell proliferation percentage changed from 100% to 71.3% and 47.0% for cells treated with 25 and 50 μg/mL GoldMag. Photothermal ablation of PANC-1 cells demonstrated an effective treatment response, specifically a reduction to only 61%, 21.9%, and 2.3% cell proliferation for cells treated with 0, 25, and 50 μg/mL GoldMag. MRI was able to visualize GoldMag uptake within PANC-1 cells.

Conclusion

Our findings suggest that photothermal ablation may be effective in the treatment of pancreatic cancer. GoldMag nanoparticles could serve as photothermal sensitizers, and MRI is feasible to quantify delivery.

Radiofrequency ablation for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related mortality worldwide. Unfortunately, only 20% of HCC patients are amenable to curative therapy (liver transplantation or surgical resection). Locoregional therapies such as radiofrequency ablation (RFA), percutaneous ethanol injection, microwave coagulation therapy, and transcatheter arterial chemoembolisation play a key role in the management of HCC. The choice of the treatment modality depends on the size of the tumour, tumour location, anatomic considerations and the number of tumours present and liver function. RFA therapy for HCC can be performed safely using a percutaneous, laparoscopic, or an open approach, even in patients with poor functional reserve. Since the introduction of RFA, several randomised controlled trials and non-randomised studies comparing RFA and other therapies for HCC have been conducted. In addition, in the last decade there have been technical advances in RFA therapy for HCC, resulting in significant improvement in the prognosis of HCC patients treated with this modality. In this review, we primarily focus on percutaneous RFA therapy for HCC and refer to current knowledge and future perspectives for this therapy. We also discuss new emerging ablation techniques.

Clinical outcome, proteome kinetics and angiogenic factors in serum after thermoablation of colorectal liver metastases

Background

Thermoablation is used to treat patients with unresectable colorectal liver metastases (CRLM). We analyze clinical outcome, proteome kinetics and angiogenic markers in patients treated by cryosurgical ablation (CSA) or radiofrequency ablation (RFA).

Methods

205 patients underwent CSA (n = 20), RFA (n = 22), partial hepatectomy (PH, n = 134) or were found truly unresectable (n = 29). Clinical outcome, proteome transitions and angiogenic response in serum were analyzed at various time points after ablation.

Result

Median overall survival in CSA patients (17.6 months) was worse (p < 0.0001) when compared to RFA treated patients (51.7 months) and patients after PH (43.4 months). The complication rate was higher in the CSA group (50%) as compared to the RFA group (22%). Proteomics analyses showed consistently more changes in serum protein abundance with CSA compared to RFA. In the first four days after ablation a pro-angiogenic serum response occurred.

Conclusions

RFA of CRLM is superior to CSA with a median survival which equals survival in patients after PH. Proteomics analyses suggests a more aggravated serum response to CSA compared to RFA. Thermoablation is associated with changes in serum levels of angiogenic factors favouring a pro-angiogenic environment, but without differences between RFA and CSA.

Outcomes of ultrasound-guided percutaneous argon-helium cryoablation of hepatocellular carcinoma

PURPOSE

To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous argon-helium cryoablation for hepatocellular carcinoma (HCC) and determine appropriate indications.

METHODS

We reviewed outcomes of 300 HCC patients who underwent US-guided percutaneous cryoablation.

RESULTS

Overall, 223 tumors (mean diameter 7.2 ± 2.8 cm) in 165 patients were incompletely ablated, while 185 tumors (mean diameter 5.6 ± 0.8 cm, P = 0.0001 vs. incomplete ablation) in 135 patients were completely ablated. Nineteen patients (6.3%) developed serious complications while in hospital, including cryoshock syndrome in six patients, hepatic bleeding in five, stress-induced gastric bleeding in four, liver abscess in one and intestinal fistulas in one. Two patients died because of liver failure. The median follow-up was 36.7 months (range 6-63 months). The local tumor recurrence rate was 31%, and was related to tumor size (P = 0.029) and tumor location (P = 0.037). The mean survival duration of patients with early, intermediate and advanced HCC (Barcelona Clinic Liver Cancer staging system) was 45.7 ± 3.8, 28.4 ± 1.2 and 17.7 ± 0.6 months, respectively.

CONCLUSIONS

US-guided percutaneous cryoablation is a relatively safe and effective therapy for selected HCC patients.