Cryoablation of unresectable malignant liver tumors

Advances in Image-Guided Ablation Therapies for Solid Tumors

Image-guided solid tumor ablation methods have significantly advanced in their capability to target primary and metastatic tumors. These techniques involve noninvasive or percutaneous insertion of applicators to induce thermal, electrochemical, or mechanical stress on malignant tissue to cause tissue destruction and apoptosis of the tumor margins. Ablation offers substantially lower risks compared to traditional methods. Benefits include shorter recovery periods, reduced bleeding, and greater preservation of organ parenchyma compared to surgical intervention. Due to the reduced morbidity and mortality, image-guided tumor ablation offers new opportunities for treatment in cancer patients who are not candidates for resection. Currently, image-guided ablation techniques are utilized for treating primary and metastatic tumors in various organs with both curative and palliative intent, including the liver, pancreas, kidneys, thyroid, parathyroid, prostate, lung, breast, bone, and soft tissue. The invention of new equipment and techniques is expanding the criteria of eligible patients for therapy, as now larger and more high-risk tumors near critical structures can be ablated. This article provides an overview of the different imaging modalities, noninvasive, and percutaneous ablation techniques available and discusses their applications and associated complications across various organs.

Percutaneous cryoablation in early stage hepatocellular carcinoma: analysis of local tumor progression factors

PURPOSE

We aimed to evaluate the effectiveness and safety of percutaneous cryoablation (PC) for early or very early stage hepatocellular carcinoma (HCC) and assess the risk factors for local tumor progression (LTP) after PC.

METHODS

A total of 45 treatment-naïve patients treated with PC for early or very early stage HCCs were included in this retrospective study. The safety of PC was assessed by evaluating procedure-related complications and comparing hepatic function before and after the procedure. The effectiveness was assessed by evaluating technical success, LTP rates, and disease progression (DP) rates. Prognostic factors associated with LTP after PC were also analyzed.

RESULTS

Technical success and complete response were achieved in all patients (100%) by 1 month after PC. During a mean of 28.1±15.6 months of follow-up, the incidences of LTP and DP were 11.1% and 37.8%, respectively. The LTP-free and DP-free survival rates were 93.3% and 84.4% at 1 year and 88.9% and 62.2% at 2 years, respectively. Hepatic function was normalized within 3 months after PC. There were no major complications and only one minor complication of small hematoma. On univariate and multivariate analysis, minimal ablative margin <5 mm was the only significant risk factor associated with LTP.

CONCLUSION

PC is a safe and effective therapy for patients with early or very early stage HCC. Minimal ablative margin <5 mm was a significant prognostic factor for LTP.

Computed Tomography Thermography for Ablation Zone Prediction in Microwave Ablation and Cryoablation: Advantages and Challenges in an Ex Vivo Porcine Liver Model

PURPOSE

The aim of this study was to investigate the diagnostic accuracy of computed tomography (CT) for the prediction of ablation zones from microwave ablation (MWA) and cryoablation (CA) in an ex vivo porcine liver model.

METHODS

Sequential (30 seconds) CT scans were acquired during and after MWA and CA in an ex vivo porcine liver model. We generated 120-kVp equivalent reconstructions of generic dual-energy CT data sets, and comprehensive region-of-interest measurements were statistically correlated with invasive temperature monitoring using Pearson correlation coefficient. Binary logistic regression was performed for prediction of successful ablation.

RESULTS

With the use of pooled data from 6 lesions in 2 separate experiments, correlation analysis of attenuation in Hounsfield units (HU) and temperature yielded r = -0.79 [confidence interval (CI), -0.85 to -0.71] for MWA and r = 0.62 (CI, 0.55 to 0.67) for CA.For MWA, there was a linear association between attenuation and temperature up to 75°C; thus, linear regression yielded a slope of -2.00 HU/°C (95% CI, -1.58 to -2.41). For CA, a linear association between attenuation and temperature was observed in the cooling phase with a slope of 2.11 HU/°C (95% CI, 1.79 to 2.58). In MWA treatment, binary logistic regression separated less than 70°C and greater than 70°C with 89.2% accuracy. Within the ice ball, temperatures above and below -20°C were distinguished with 65.3% accuracy.

CONCLUSIONS

Our experiments reveal several difficulties in predicting ablation zone temperature from CT attenuation. Microwave ablation leads to gas production in the tissue, which degrades the accuracy of noninvasive temperature measurement, especially at higher temperatures. In CA, CT thermometry is limited by ice ball formation, which leads to homogeneous attenuation, nearly independent of temperature. Further research is needed to define the role of CT thermography in ablation zone monitoring in liver malignancies.

Imaging findings during and after percutaneous cryoablation of hepatic tumors

OBJECTIVE

Imaging plays a key role in the assessment of patients before, during, and after percutaneous cryoablation of hepatic tumors. Intra-procedural and early post-procedure imaging with CT and MRI is vital to the assessment of technical success including adequacy of ablation zone coverage. Recognition of the normal expected post-procedure findings of hepatic cryoablation such as ice ball formation, hydrodissection, and the normal appearance of the ablation zone is crucial to be able to differentiate from complications including vascular, biliary, or non-target organ injury. Delayed imaging is essential for determination of clinical effectiveness and detection of unexpected findings such as residual unablated tumor and local tumor progression. The purpose of this article is to review the spectrum of expected and unexpected imaging findings that may occur during or after percutaneous cryoablation of hepatic tumors.

CONCLUSION

Differentiating expected from unexpected findings during and after hepatic cryoablation helps radiologists identify residual or recurrent tumor and detect procedure-related complications.

Irreversible electroporation of malignant liver tumors: Effect on laboratory values

Liver cancer is often associated with chronic liver diseases. Treatment with percutaneous irreversible electroporation (IRE) may preserve liver function. In the present study, the clinical data of 29 patients with liver tumors between July 2015 and December 2016, all of whom underwent liver IRE at Fuda Cancer Hospital, Guangzhou, China was retrospectively reviewed. All the patients survived the treatment. Of the 29 patients, 7 were positive for hepatitis B, 15 had hepatocellular carcinoma (HCC) and 7 had pancreatic cancer with liver metastases. All patients survived IRE. Despite liver-protective treatment prior to IRE, the mean alanine transaminase (ALT) and aspartate transaminase (AST) levels were significantly elevated 1-2 days after IRE, to 540 and 712 U/l, respectively; however they had returned to the preoperative values by 2 weeks following IRE. Prior to IRE, the mean total bilirubin and direct bilirubin measurement levels were normal; however, 8-10 days after IRE, they had increased to 24 U/l and 12 µmol/l, respectively, and had returned back to the preoperative levels by 2 weeks after IRE. This first group included all patients. The result of the 4 subgroups of cancer patients demonstrated a variation between different measurement days and recovery with patients positive for the hepatitis B virus taking the longest duration to recover (17±3 days) meanwhile patients with pancreatic cancer with liver metastases took the shortest time to achieve recovery (10.78±2 days). The findings of the present study indicate that hepatic injury caused by IRE is transient and self-limiting in patients with liver tumors.

Multimodality Therapy Including Proton Beam Therapy for AFP Producing Esophageal Cancer with Multiple Liver Metastases

A 50-year-old man who presented with a fever and epigastralgia was diagnosed to have esophageal carcinoma which was identified as poorly differentiated adenocarcinoma producing alpha-fetoprotein (AFP) with Barrett's esophagus. Computed tomography revealed multiple liver metastases and lymph node metastases surrounding the stomach. We first performed chemotherapy for the systemic lesions and proton beam therapy for the local control of lesions without complete remission and we were able to successfully control the frequently recurring lesions by proton beam therapy, cryotherapy and chemotherapy. A complete response has been maintained for 16 months and the overall survival time is 4 years and 2 months. Proton beam therapy for primary esophageal cancer and metastatic lesions was thus found to be an effective therapeutic option for such cases.

Technology of irreversible electroporation and review of its clinical data on liver cancers

INTRODUCTION

Irreversible electroporation (IRE) has developed as a novel percutaneous ablative technique over the past decade and its utility in the treatment of primary and metastatic liver disease has progressed rapidly.

AREAS COVERED

After discussing the principles behind the technology and the practical steps in its use, this article offers a detailed analysis of the recent published work that evaluates its safety and efficacy. The strengths and weaknesses of other ablative techniques, including radiofrequency ablation, microwave ablation and cryoablation, are discussed in detail. Other aspects of IRE, including post-treatment clinical follow-up, expected imaging findings, and the most frequently encountered complications, are covered. Finally, the future of IRE is examined as it pertains to advancements in the treatment of hepatic malignancy.

EXPERT COMMENTARY

The characteristics of IRE that make this technology uniquely suited for the treatment of liver tumors have allowed it to gain a significant foothold in interventional oncology. Continued development of IRE will lead to further advances in the management of previously untreatable liver cancers.

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.

Cryoprotective therapy for huge hepatocellular carcinoma: a study of 14 patients with a single lesion

Percutaneous cryoablation is a potential cure for hepatocellular carcinoma (HCC). This study reviewed retrospectively clinical data from 14 patients who underwent cryoablation of huge HCC (long diameter >7 cm). The side effects of cryosurgeries and liver function reverse were recorded and compared everyday. All the patients survived cryosurgery and none died before leaving hospital 2 weeks later. Despite liver-protective treatment before cryosurgery, alanine transaminase (ALT) and aspartate transaminase (AST) levels were increased significantly, but returned to preoperative levels 2 weeks post-cryosurgery. Before cryosurgery, mean total bilirubin (T.BIL) and direct bilirubin (D.BIL) levels were normal; 8-10 days after cryosurgery, they increased more than two-fold, but returned to the preoperative level 2 weeks post-cryosurgery. Serum transaminase and bilirubin levels were compared between hepatitis B positive and negative patients. The hepatitis B negative group's AST level increased significantly 1 day post-cryosurgery (mean, 186 U/L) and decreased to the preoperative level at day 14. In the hepatitis B positive group, means transaminase and bilirubin reached peak values at different days post-cryosurgery. Overall, ALT and AST are valuable indicators of liver function impairment following cryosurgery. In patients with hepatitis B virus, close attention to the serum bilirubin level should be paid 8-10 days after cryosurgery. Liver-protective treatment may alleviate liver function impairment caused by cryosurgery of huge HCC.

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.

Cryoprotective therapy for hepatocellular carcinoma: study of 51 patients with a single lesion

Percutaneous cryoablation is a potentially curative treatment for hepatocellular carcinoma (HCC). After liver cryosurgery, rapid elevations of transaminases and bilirubin are common, but are usually transient and normalize within a few days. This study retrospectively reviewed clinical data from 51 patients who underwent liver cryoablation in our hospital during the past 4.5 years. Sixty-six percutaneous cryoablations were performed in these patients and transaminase and bilirubin levels before and after the procedure were observed. Although most patients received liver-protective treatment before cryosurgery, transaminase levels were double (mean alanine transaminase (ALT) and aspartate transaminase (AST) were 71 U/L and 85 U/L, respectively) the normal ranges in our hospital. One day after cryosurgery, ALT and AST had increased 3.3-fold (peak mean was 241 U/L) and 5-fold (peak mean was 427 U/L), respectively, but were close to the preoperative level 5 days post-cryosurgery. No significant increase of serum bilirubin was observed. Serum transaminase and bilirubin levels were compared between hepatitis B positive and hepatitis B negative patients. Only in the hepatitis B positive group were total bilirubin (74 μmol/L/23 μmol/L=3.2) and direct bilirubin (45 μmol/L/12 μmol/L=3.8) more than 3 times the preoperative level 7-9 days after treatment. Overall, ALT and AST are valuable as indicators of liver function impairment following cryosurgery. In patients with hepatitis B virus, serum bilirubin was 3 times the preoperative level 7-9 days after cryosurgery. Liver-protective treatment may alleviate liver function impairment due to cryosurgery.

Feasibility and oncologic control after percutaneous image guided ablation of metastatic renal cell carcinoma

PURPOSE

We assessed the safety, local control and oncologic efficacy of percutaneous ablation in the treatment of metastatic renal cell carcinoma.

MATERIALS AND METHODS

A retrospective review was performed of 61 patients who underwent 74 ablation procedures to treat 82 metastatic renal cell carcinoma lesions with the intent of local eradication. Technical success, local tumor control, complications and patient survival were analyzed according to standard criteria.

RESULTS

Four (4.9%) technical failures were observed while 2 patients were lost to followup. Time to recurrence was assessed for the subset of 76 (93%) tumors that were followed after ablation. Six (of 76, 7.9%) tumors recurred at a mean of 1.6 years after ablation (median 1.4, range 0.6 to 2.9). Thus, known overall local tumor control was achieved in 70 of 80 (87.5%) tumors. Estimated local recurrence-free survival rates (95% CI, number still at risk) at 1, 2 and 3 years after ablation were 94% (88-100, 41), 94% (88-100, 32) and 83% (70-97, 17), respectively. Estimated overall survival rates (95% CI, number still at risk) at 1, 2 and 3 years after ablation were 87% (79-97, 42), 83% (73-94, 31) and 76% (63-90, 19), respectively.

CONCLUSIONS

Image guided ablation of metastatic renal cell carcinoma is a relatively safe procedure with acceptable local control rates. Ablation may offer patients a minimally invasive option of local tumor eradication and warrants a role in the multimodal treatment approach for select patients.

Contrast-enhanced ultrasound (CEUS) follow-up after radiofrequency ablation or cryoablation of focal liver lesions: treated-area patterns and their changes over time

OBJECTIVES

To describe the early patterns of liver lesions successfully treated with radiofrequency ablation (RFA) or cryoablation (CA) and their changes over time.

METHODS

Twenty-two RFA-treated and 17 CA-treated patients underwent CEUS from week 1 to year 3 post-ablation. Patterns, margins and volumes of RF-induced and cryolesions were evaluated and compared over time.

RESULTS

After contrast enhancement, shortly after ablation, undefined margins with persistent enhancing small vessels penetrating >2 mm into the treated zone were significantly more frequent after CA (67 %) than RFA (22 %) (P < 0.02). During the arterial phase, a thin, enhancing marginal rim was seen during week 1 (T1) in around 28 % of RF lesions, while 75 % of cryolesions had thick enhancing rims (P < 0.02). The mean RF-induced lesion volume, maximum at T1 (44.1 ± 37.5 ml), shrank slowly over time, remaining clearly visible at 1 year (8.3 ± 7.4 ml). Cryolesions shrank faster (P = 0.009), from an average of 16.6 ± 7.1 ml at T1 to 1.7 ± 1.3 ml 1-year post-ablation.

CONCLUSION

RF-induced and cryolesions differ, particularly their margins and shrinkage rates. Knowing these differences allows avoidance of incomplete treatment or falsely diagnosed recurrence, especially after CA.

KEY POINTS

• Contrast-enhanced ultrasound (CEUS) provides new follow-up information following hepatic radiological inyervention. • CEUS provides good visualisation of vascular modifications after thermoablation. • RFA-induced lesions and cryoablated lesions differ. • Knowledge about RF and cryolesion patterns is essential for correct CEUS follow-up. • Cryolesions have thicker peripheral inflammatory reactions and shrink faster than RFA-induced lesions.

Percutaneous cryoablation of small hepatocellular carcinomas using a 17-gauge ultrathin probe

AIM

To evaluate the feasibility and safety of percutaneous cryoablation (PCA) of small hepatocellular carcinomas (HCCs) using a 17 G ultrathin cryoprobe.

MATERIALS AND METHODS

Twenty patients (male:female ratio14:6) with 20 HCCs, who were not surgical candidates, underwent ultrasound (US)-guided PCA for treatment of HCCs. Single HCCs less than 3cm in diameter were included in this study. Ablation was performed using a 17 G cryoprobe. The effectiveness was determined by the changes in alpha-foetoprotein level and degree of tumour necrosis on follow-up computed tomography (CT); complete response (100% necrosis), partial response (100%>necrosis≥30%), stable disease (any cases not qualifying for either partial response or progressive disease) and progressive disease (increase of at least 20% in diameter of viable tumour). Haemoglobin, white blood cell count (WBC), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and total bilirubin were compared before and after the procedure, and the technical feasibility, complications, clinical outcomes and survival of each patient were also evaluated.

RESULTS

All procedures were technically successful. Each patient complained of negligible pain and there was no other procedure-related complication or mortality. The mean level of alpha-foetoprotein declined significantly from 53.2 to 20.4ng/ml 1 month after the procedure (p<0.05). At 1-month follow-up CT, there were 13 complete responses, four partial responses, three patients with stable disease, and no patients had progressive disease. Six of seven lesions that did not present with a complete response underwent further treatment. On long-term follow up (6-30 months; mean 20.7), a local recurrence was seen in one of 13 lesions (8%) with complete response revealed. Laboratory findings showed no significant changes except for the transient increase of SGOT and SGPT.

CONCLUSION

US-guided PCA using a 17 G cryoprobe was feasible and safe for the treatment of HCC smaller than 3cm.

Recent progress in the understanding, diagnosis, and treatment of gastroenteropancreatic neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are relatively rare tumors that arise from the diffuse neuroendocrine system. This heterogeneous group of tumors was often considered a single entity. This belied their biological diversity, and the biggest advance in understanding these tumors over the past decades has been in understanding this diversity. Diagnosis of these tumors has been aided by advances in pathological diagnosis and classification and tumor imaging with endoscopic ultrasound and somatostatin receptor fusion imaging. Genetic and molecular advances have identified molecular targets in the treatment of these tumors. Surgery remains the mainstay of treatment, amply supported by interventional radiological techniques, including embolization. Treatment of metastatic disease has improved significantly with the addition of several new agents, including tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, and yttrium-90-DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and lutetium-177-DOTA octreotate. Despite significant advances in the understanding and management of GEP-NETs, the survival of patients remains largely unchanged and there remains a need for the development of national and international research collaborations to spearhead future efforts.

Multimodal management of neuroendocrine liver metastases

BACKGROUND

The incidence of neuroendocrine tumours (NET) has increased over the past three decades. Hepatic metastases which occur in up to 75% of NET patients significantly worsen their prognosis. New imaging techniques with increasing sensitivity enabling tumour detection at an early stage have been developed. The treatment encompasses a panel of surgical and non-surgical modalities.

METHODS

This article reviews the published literature related to management of hepatic neuroendocrine metastases.

RESULTS

Abdominal computer tomography, magnetic resonance tomography and somatostatin receptor scintigraphy are widely accepted imaging modalities. Hepatic resection is the only potentially curative treatment. Liver transplantation is justified in highly selected patients. Liver-directed interventional techniques and locally ablative measures offer effective palliation. Promising novel therapeutic options offering targeted approaches are under evaluation.

CONCLUSIONS

The treatment of neuroendocrine liver metastases still needs to be standardized. Management in centres of expertise should be strongly encouraged in order to enable a multidisciplinary approach and personalized treatment. Development of molecular prognostic factors to select treatment according to patient risk should be attempted.

Pedicle frozen autograft reconstruction in malignant bone tumors

BACKGROUND

Standardizing limb salvage surgery for malignant bone tumors should result in improved limb function after tumor excision and reconstruction. Recently, we developed and clinically applied a method of biological reconstruction using tumor-bearing autografts treated with liquid nitrogen. We report this newly modified technique using pedicle frozen autografts to save the continuity of anatomical structures.

METHODS

We treated 33 malignant bone tumor patients. Diagnoses of the tumors were 17 osteosarcomas, 11 metastatic tumors, 2 Ewing's sarcomas, 2 chondrosarcomas, and 1 undifferentiated pleomorphic sarcoma. The sites of the tumors were 23 femurs, 5 tibias, 4 humeri, and 1 calcaneus. Operative procedures consisted of exposing the tumor, performing one-site osteotomy or joint dislocation, rotating and freezing the tumor lesion in liquid nitrogen for 20 min, and reconstruction using intramedullary nailing, plates, or composite arthroplasty.

RESULTS

Postoperative function was excellent in 25 patients (75.7%), good in 5 patients (15.1%), and fair in 3 patients (9.0%). At the final follow-up, 8 patients had died at a mean of 17 months postoperatively, and 18 patients remained disease-free for a mean follow-up period of 30 months (range 7-69 months). Seven patients were alive but with disease. Complications were encountered in 12 patients, including 4 deep infections, 3 fractures, 3 local recurrences from surrounding soft tissue, 2 nonunions, and 1 collapse. All were managed successfully.

CONCLUSIONS

The pedicle frozen autograft, which was newly developed to solve drawbacks of previously reported free frozen autografts, achieved success for reconstruction of malignant bone tumors. This is a new, simple, effective surgical technique for biological reconstruction that is still investigated but has potential for development.

Cryotherapy for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma is the most common primary malignant cancer of the liver. Evidence for the role of cryotherapy in the treatment of hepatocellular carcinoma is controversial.

OBJECTIVES

The aim of this review is to evaluate the potential benefits and harms of cryotherapy for the treatment of hepatocellular carcinoma.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and LILACS until June 2009. We identified further studies by searching national and topic-specific databases, bibliographies, conference abstracts, journals, and grey literature. Furthermore, we reviewed the reference lists and contacted the principal authors of the identified studies.

SELECTION CRITERIA

Randomised clinical trials (irrespective of language or publication status) comparing cryotherapy with or without co-intervention(s) to placebo, no treatment, or other control interventions were considered for the review. Due to the absence of randomised clinical trials, we searched for quasi-randomised studies as well as prospective cohort studies and retrospective cohort studies.

DATA COLLECTION AND ANALYSIS

Two authors independently identified and assessed studies for their fulfilment of the inclusion criteria. Dichotomous data were expressed as risk ratio (RR) with 95% confidence intervals (CI). We performed the review following the recommendations of The Cochrane Collaboration.

MAIN RESULTS

We were unable to identify any randomised clinical trials. We were also unable to identify quasi-randomised trials. Instead, we identified two prospective cohort studies and two retrospective cohort studies. However, only one of these studies could be included for the assessment of benefit as the study results were stratified according to both the type of hepatic malignancy (primary or secondary) and the intervention group. This retrospective study compared percutaneous cryotherapy with percutaneous radiofrequency. The remaining studies were excluded for the analyses of benefit but included for the assessment of harm. Both severe and non-severe adverse events were reported, but the true nature and extent of harm was difficult to asses.

AUTHORS' CONCLUSIONS

At present, there is no evidence to recommend or refute cryotherapy for patients with hepatocellular carcinoma. Randomised clinical trials with low-risk of bias may help in defining the role of cryotherapy in the treatment of hepatocellular carcinoma.

Surgical management of metastases to the adrenal gland: open, laparoscopic, and ablative approaches

The adrenal gland is a potential site of metastasis for various malignancies. Metastases to the adrenal gland are the second most common type of adrenal mass lesion after adenomas. Differentiation of a metastatic lesion from a primary adrenal lesion can be challenging and requires the selective use of radiologic imaging, serologic testing, and adrenal biopsy. In patients who present with an isolated adrenal metastasis, adrenalectomy is often considered to aid in cancer control. Numerous studies have reported improved survival with resection of solitary adrenal metastases for various types of primary tumors. Traditionally, open adrenalectomy was the preferred option for these patients. More recently, laparoscopic adrenalectomy has offered a minimally invasive approach, with its resultant advantages of improved perioperative parameters. Proper patient selection for the laparoscopic versus open approach remains paramount in deciding the best treatment for the individual patient.

Interventional neuroradiology of the head and neck

Interventional neuroradiology procedures are a valuable asset in the diagnosis, treatment, and surgical management of various disorders affecting the extracranial head and neck. A detailed understanding of cross-sectional and vascular anatomy and an awareness of potential collateral pathways between extracranial and intracranial vessels are essential for ensuring safe and successful procedures. With the use of high-quality imaging and a meticulous technique, the incidence of major complications is extremely low.

Cryosurgery for hepatocellular carcinoma

Cryosurgery is an important treatment modality for unresectable hepatocellular carcinoma (HCC). There are different forms of cryosurgery for HCC including intraoperative cryoablation with or without excision, laparoscopic liver cryosurgery, percutaneous liver cryoablation under the guidance of ultrasonography, CT or MRI. Cryoablation, as a local therapy for HCC, has certain advantages over other forms of treatment. It is able to destroy only tumor tissue in the liver while sparing more noninvolved tissues. Tumors close to the vessel systems can safely undergo cryoablation due to the warming effect of circulating blood in large blood vessels. Liver cryoablation is more effective than surgical resection for multiple liver tumors. Cryosurgery in combination with transarterial chemoembolization (TACE), alcohol injection or ¹²⁵iodine seed implantation has a complementary efficacy. Clinically, cryosurgery for HCC is performed according to the following principles. Intraoperative or percutaneous cryosurgery may be performed for liver tumors < 5 cm or ≤3 cm, TACE for liver tumors > 5 cm followed by percutaneous cryosurgery. Liver tumors > 5 cm with an irregular margin, may also undergo intraoperative or percutaneous cryosurgery followed by alcohol injection or ¹²⁵iodine seed implantation in the margins of tumors.

Recurrence and Survival Outcomes after Hepatic Resection with or without Cryotherapy for Liver Metastases from Colorectal Carcinoma

BACKGROUND

Some reports support resection combined with cryotherapy for patients with multiple bilobar colorectal liver metastases (CRLM) that would otherwise be ineligible for curative treatments. This series demonstrates long-term results of 415 patients with CRLM who underwent resection with or without cryotherapy.

METHODS

Between April 1990 and January 2006, 291 patients were treated with resection only and 124 patients with combined resection and cryotherapy. Recurrence and survival outcomes were compared. Kaplan-Meier and Cox-regression analyses were used to identify significant prognostic indicators for survival.

RESULTS

Median length of follow-up was 25 months (range 1-124 months). The 30-day perioperative mortality rate was 3.1%. Overall median survival was 32 months (range 1-124 months), with 1-, 3- and 5-year survival values of 85%, 45% and 29%, respectively. The overall recurrence rates were 66% and 78% for resection and resection/cryotherapy groups, respectively. For the resection group, the median survival was 34 months, with 1-, 3- and 5- year survival values of 88%, 47% and 32%, respectively. The median survival for the resection/cryotherapy group was 29 months, with 1-, 3- and 5-year survival values of 84%, 43% and 24%, respectively (P = 0.206). Five factors were independently associated with an improved survival: absence of extrahepatic disease at diagnosis, well- or moderately-differentiated colorectal cancer, largest lesion size being 4 cm or less, a postoperative CEA of 5 ng/ml or less and absence of liver recurrence.

CONCLUSIONS

Long-term survival results of resection combined with cryotherapy for multiple bilobar CRLM are comparable to that of resection alone in selected patients.

Cytotoxic treatment including embolization/chemoembolization for neuroendocrine tumours

In patients with advanced neuroendocrine tumours, surgery is curative in only a minority of cases, whilst the anti-tumour effect of somatostatin analogues, despite efficient symptom control, is limited. Systemic chemotherapy has been proved to be effective only in certain tumour types. Although metastatic midgut carcinoids and well-differentiated gastrointestinal carcinoids are relatively insensitive to chemotherapy, pancreatic neuroendocrine tumours show a response rate of around 40% to streptozotocin-based combinations, particularly with fluorouracil and doxorubicin. Poorly differentiated tumours respond even better, especially to a combination of cisplatin and etoposide. In patients with predominant liver disease, ischaemia of tumour lesions induced by vascular occlusion by particle embolization or chemoembolization may be considered. This may have clinical and biochemical responses up to 80%, and objective responses up to 60%, in disease which is progressive despite previous treatments. Potential adverse effects and short duration of response should be taken into account.

Cryosurgery for resectable and unresectable hepatic metastases from colorectal cancer

AIMS

Hepatic cryosurgery is useful for patients with hepatic metastases from colorectal cancer confined to the liver but considered unresectables because of the number and location of lesions. While encouraging results were reported following cryosurgery for unresectable liver metastases we considered particularly valuable to examine the safety and effectiveness of cryosurgery in patients with resectable and unresectable metastases from colorectal cancer.

METHODS

Between January 1997 and September 2005, 53 patients with liver metastases from colorectal cancer underwent hepatic cryosurgery at our institution. Hepatic metastases were resectable in 31 (58.5%) patients and unresectable in 22 (41.5%).

RESULTS

A total of 136 liver metastases were treated in 53 patients. The size of treated lesions ranged from 0.5 to 10 cm (mean 2.7). There were 2 postoperative deaths (3.8%) from massive bleeding and from cryoshock. The overall morbidity rate was 66%. The median follow-up was 24.8 months. The overall survival rate at 12 months was 86.1%, at 48 months it was 27%. No significant difference was found between survival rates in patients with resectable or unresectable metastases. Among 31 patients with resectable liver metastases 7 (22.6%) patients developed recurrence at the site of cryosurgery.

CONCLUSION

Survival rates were comparables between patients with resectable and unresectable metastases but a high complication rate and a substantial rate of local recurrence following cryosurgery should caution against its use to treat resectable disease.

Update on the management of neuroendocrine hepatic metastases

Neuroendocrine tumors (NETs) are rare and represent a diverse collection of malignancies that occur in many organ systems throughout the body, including the gastrointestinal and respiratory tracts. Unfortunately, the majority of patients with NETs have hepatic metastases at the time of diagnosis. Although some patients may be asymptomatic, others have unusual clinical presentations and variable tumor growth patterns. Although many patients have long indolent courses, without treatment, most patients die within 5 years of diagnosis. This article reviews the care of patients with NETs and hepatic metastases, with emphasis on the increasingly important role of oncologic image-guided interventions.

Complement depletion enhances pulmonary inflammatory response after liver injury

Hepatic cryoablation can produce acute lung injury, with activation of nuclear factor (NF)-kappaB in the remnant liver and lungs, production of C-X-C chemokines, and neutrophil infiltration of the lungs. Activated complement stimulates NF-kappaB and cytokine secretion from Kupffer cells. The role of complement in the development of acute lung injury after cryoablation was examined using HLL transgenic mice (5'HIV-LTR-Luciferase gene; 5' HIV-LTR is an NF-kappaB-dependent promoter). Total complement depletion was achieved with preoperative administration of cobra venom factor (CVF). After hepatic cryoablation, bioluminescent NF-kappaB activity increased in the nonablated liver remnant by 4 hours in both control (119,093 +/- 22,808 net RLU/mg protein) and CVF-treated mice (117,722 +/- 14,932) from cumulative baseline (657 +/- 90, P < 0.0001). In the lung, complement-depletion induced significantly greater increases in NF-kappaB activation at both early and later times. Likewise, chemokines were higher in complement-depleted mice relative to controls (KC: 493 +/- 43 versus 269 +/- 29 pg/mg protein, P < 0.001; MIP-2: 171 +/- 29 versus 64 +/- 13 pg/mg protein, P < 0.0001). Pulmonary myeloperoxidase activity was equivalent at 24 hours, but complement-depletion caused a significantly more rapid influx of neutrophils. Complement depletion results in increased pulmonary inflammation following liver cryo injury via relative upregulation of NF-kappaB activity. Activated complement is not the initiator of the systemic inflammatory response; in fact, downstream components of the complement cascade may diminish subsequent inflammation.

Malignant Hypertension during Cryoablation of an Adrenal Gland Tumor

The authors report a case of hypertensive crisis during cryoablation of an adrenal metastasis. This case is of particular interest not only because of the nature of the complication but also because of the timing of the hypertensive crisis. Based on their observations, the authors suggest that it may be prudent to pretreat this patient population with alpha-adrenergic blocking medications (eg, phenoxybenzamine), as is typically done for patients with neuroendocrine tumors such as pheochromocytoma. Preemptive intervention with these medications requires close collaboration between radiology and anesthesia care teams.

Liver resection or cryotherapy for colorectal liver metastases: a prospective case control study

BACKGROUND AND AIMS

While there is promising survival data for cryosurgery of colorectal liver metastases, local recurrence following cryoablation remains a problem. We aimed to compare morbidity and mortality, as well as the recurrence pattern and survival after liver resection and cryotherapy (alone or in combination with resection) for liver metastases.

PATIENTS AND METHODS

Between 1996 and 2002, 168 patients underwent liver resection alone and 55 patients had cryotherapy (25 in combination with liver resection) for colorectal liver metastases. The patient, tumour and operative details were recorded prospectively and the two patient groups were compared regarding morbidity, survival and recurrence.

RESULTS

More patients had a prior liver resection, liver metastases were smaller and less frequently synchronous, morbidity was significantly lower and hepatic recurrence was significantly more frequent in the cryotherapy group. Five-year survival rates following resection and cryotherapy were comparable (23 and 26% respectively), while overall and hepatic recurrence-free survival was inferior following cryotherapy.

CONCLUSION

Cryotherapy is a valuable treatment option for some patients with non-resectable colorectal liver metastases. While survival is comparable to that after resection, higher hepatic recurrence rates following cryotherapy should caution against the use of cryotherapy for resectable disease until the results of randomized controlled trials are available.

Hepatic hemorrhage caused by percutaneous tumor ablation: radiofrequency ablation versus cryoablation in a porcine model

PURPOSE

To determine the extent of hepatic hemorrhage caused by percutaneous cryoablation performed with a small-diameter cryoablation probe compared with that caused by percutaneous radiofrequency (RF) ablation in a porcine model.

MATERIALS AND METHODS

The study was pre-approved by the institutional research animal care and use committee, and husbandry and experiments complied with National Institutes of Health standards for care and use of laboratory animals. Percutaneous hepatic ablation was performed in 18 domestic pigs (mean weight, 45 kg) by using a 17-gauge (1.5-mm-diameter) RF electrode (n = 6), a cluster of three RF electrodes (n = 6), or a 13-gauge (2.4 mm-diameter) cryoprobe (n = 6). Ablation was performed in four sites per liver. Total blood loss, minimum lesion diameter, maximum lesion diameter, and lesion volume were determined for each group and compared by using analysis of variance.

RESULTS

Mean blood loss was 11.11 mL +/- 11.47 (standard deviation), 105.29 mL +/- 175.58, and 28.06 mL +/- 30.97 with the single RF electrode, RF electrode cluster, and cryoablation probe, respectively. Mean minimum and maximum lesion diameters were largest with the RF electrode cluster (2.40 and 3.98 cm, respectively), followed by the cryoablation probe (2.38 and 3.94 cm) and single RF electrode (1.49 and 2.63 cm). Mean minimum and maximum lesion diameters were significantly different between the single RF electrode and the RF electrode cluster, as well as between the single RF electrode and the cryoablation probe (P < .001). Mean lesion volume was largest for the RF electrode cluster (24.03 cm3), followed by those for the cryoablation probe (17.46 cm3) and single RF electrode (9.05 cm3) (single RF electrode vs cryoablation probe, P < .05). Lesion volumes were not significantly different with the RF electrode cluster versus the single RF electrode (P = .052) or with the RF electrode cluster versus the cryoablation probe (P = .381).

CONCLUSION

Mean blood loss from percutaneous cryoablation in this model was between that for RF ablation with the single electrode and that for RF ablation with the electrode cluster.

Chemoembolization and other ablative therapies for liver metastases of gastrointestinal endocrine tumours

Hepatic metastases are frequent in patients with gastroentero-pancreatic (GEP) endocrine tumours; their presence significantly influences overall prognosis. Surgery, although the treatment of choice for hepatic metastases, is frequently impossible due to disease extent. Systemic chemotherapy in patients with diffuse and/or progressive liver metastases yields disappointing results especially in patients with metastases from midgut origin. In addition, in patients with carcinoid syndrome, the efficacy of somatostatin analogues wanes due to disease progression and development of tachyphylaxis. Locoregional strategies with vascular occlusion inducing ischemia in these highly vascular GEP tumours are indeed other options and may be performed using either surgical or radiological techniques (e.g. surgical ligation of the hepatic artery, transient hepatic ischemia, or sequential hepatic arterialization). Trans-catheter arterial chemoembolization is efficacious in both the control of hormonal symptoms and yields reliable objective tumour responses. Treatments aimed at regional destruction either alone or in combination with surgery include radiofrequency ablation and cryotherapy and may also be considered in certain circumstances.

Laparoscopic Adrenal Surgery: New Frontiers

After about 10 years of experience, laparoscopic adrenalectomy has become the gold standard for the treatment of adrenal lesions. Here, we describe the presenting features, imaging methods, and current surgical approaches to diseases of the adrenal gland. There is general agreement on the suitability of the laparoscopic approach for benign adrenal lesions, but controversy exists about using laparoscopy for suspected adrenal malignancy, metastasis, and partial adrenalectomy. This article reviews the literature on laparoscopic adrenalectomy. In particular, we focus our attention on the new surgical approaches to the gland. We evaluate the indications, operative techniques, and tools for partial adrenalectomy, and we discuss new surgical strategies such as cryosurgery and radiofrequency ablation.

Cryosurgery of the adrenal gland

Adrenalectomy has become the standard of care for the management of hormonally active adrenal masses. Minimally invasive adrenal-sparing surgical techniques have recently been introduced for the treatment of benign adrenal lesions, with the intent of complete excision or destruction. Cryosurgery is one such modality that is focused on reducing patient morbidity and hastening postoperative recovery, while preserving normal tissue. The emerging interest in cryosurgery is attributable to improved delivery systems and advances in radiologic imaging. However, questions remain about the risks and benefits of this technology for adrenal-sparing surgery in terms of safety and effective tissue destruction. We examine our experience and discuss our results with open and laparoscopic adrenal cryosurgery.

Cryotherapy for liver tumors: current status, perspectives, clinical results, and review of literature

Cryotherapy has gained importance as a locally ablative treatment option for patients with non-resectable liver tumors, especially metastases from colorectal cancer. We have used this technique since 1996 for the treatment of 77 patients with malignant liver tumors. Patient data was prospectively recorded and follow-up was until September 2002 or death. Fifty-five patients had colorectal cancer liver metastases, 16 metastases from other primaries and 6 had hepatoma. Forty patients had cryotherapy only and 37 had an additional liver resection. Morbidity and mortality were 22% and 1.3%, respectively. In 68% of patients with colorectal liver metastases and an elevated serum carcinoembryonic antigen-level preoperatively, it returned to the normal range following cryosurgery. For all 77 patients, median survival was 28 months with a 3- and 5-year-survival rate of 39% and 26%, respectively, and median survival was 29 months with a 3- and 5-year-survival rate of 44% and 26%, respectively, for the 55 patients with colorectal liver metastases. Local recurrence at the cryosite was observed in 13 of 65 patients (20%) with initially complete treatment. For cryotherapy to further establish as a treatment for malignant liver tumors in a time where many new local ablative techniques are developing, different goals need to be achieved. The trauma of the procedure and local treatment failure need to be minimized and survival results need to be optimized. Published studies and new possible fields of research regarding these goals are discussed.

A pig model of hepatic cryotherapy. In vivo temperature distribution during freezing and histopathological changes

We aimed to assess the temperature distribution in the cryolesion during hepatic cryotherapy and the association with postoperative histological changes to optimise the technique and allow better preoperative planning. Hepatic cryolesions were produced in 22 pigs following laparotomy using a CMS-cryosystem and 8mm-AccuProbe-Cryoprobes. The temperature was measured in 1 min intervals at different distances from the probe during freezing. The animals were treated in 5 groups: (i) single freezing of 20 min; (ii) double freezing of 20 min each; (iii) single freezing of 40 min; (iv) single freezing of 20 min (n=4), histology at 1 week p.o., and (v) single freezing of 20 min and Pringle manoeuvre; [(i)-(iii) and (v): histology at 24 h p.o.]. The mean diameter of the -38 degrees C isotherm, i.e., the zone of effective treatment for colorectal metastases was 37 mm for group (i) with a mean iceball diameter of 59 mm and about 46 mm for groups (ii, iii, and v) with mean iceball diameters of 78, 75, and 75 mm, respectively. At 7 days postoperatively secondary necrosis was seen in the largest central part of the lesion, wherever temperatures of -15 degrees C or lower were achieved during cryosurgery. Under the hypothesis that -38 degrees C is the effective temperature for the destruction of colorectal liver metastases, a lesion of 37-mm diameter may be effectively treated with a single 8mm-AccuProbe-Cryoprobe and a 20 min single freeze cycle and a lesion of 46 mm may be effectively treated when a double freeze-thaw cycle of 20 min each, a single freeze cycle of 40 min, or a 20 min single freeze cycle with additional Pringle manoeuvre is used, when it is perfectly placed in the lesion.

Prognostic factors for cryotherapy of colorectal liver metastases

BACKGROUND

Cryotherapy is a local ablative treatment option for non-resectable liver tumours. We aimed to identify prognostic indicators, that may allow better selection or stratification for adjuvant therapies of patients.

METHODS

Fifty-five patients had cryotherapy for colorectal liver metastases. The patient-, tumour- and operative details were recorded prospectively. Mean follow up was 24 months. A uni- and multivariate analysis for possible prognostic factors was performed.

RESULTS

There was a trend towards better survival for patients with unilobar liver metastases, preoperative serum levels of carcinoembrional antigen (CEA) not exceeding 20 ng/ml and patients undergoing 'R0'-treatment. Patients with multiple or large (>4 cm) liver metastases, patients undergoing cryotherapy combined with liver resection and patients receiving blood transfusion intraoperatively, especially when exceeding 4 units packed red cells, had a significantly impaired survival in univariate analysis. In multivariate analysis (Cox regression) the amount of intraoperative blood transfusion was the only independent prognostic indicator.

CONCLUSION

Intraoperative blood transfusion has a negative impact on survival following hepatic cryotherapy for colorectal liver metastases and should be avoided by refinement of surgical technique whenever possible. Patients with multiple liver metastases or metastases of more than 4 cm in size have an impaired prognosis-therefore trials of adjuvant therapies following hepatic cryotherapy for colorectal liver metastases should include number and size of metastases for stratification of patient groups.

Ablative therapies for liver metastases of gastroenteropancreatic endocrine tumors

Hepatic metastases are frequent in patients with gastroenteropancreatic (GEP) endocrine tumors. The presence of hepatic metastases affects overall prognosis and quality of life especially in the presence of debilitating functional syndromes. Surgery, although the method of choice for hepatic metastases, is usually impossible due to disease extent. Results of systemic chemotherapy are also disappointing especially in patients with metastases from midgut GEP tumors. These latter patients usually have carcinoid syndrome which can be controlled by somatostatin analogues. Other therapeutic options in the treatment of highly vascular liver metastases from GEP tumors are locoregional strategies by inducing vascular occlusion resulting in ischemia and necrosis of tumoral tissue. Surgical ligation of the hepatic artery or transient hepatic ischemia has been replaced by transcatheter arterial chemoembolization (TACE). TACE has proven effective in controlling symptoms and gives objective tumor response in about half of patients. Other regional destructive methods, used either alone or in combination with surgery, include radiofrequency ablation and cryotherapy. The latter strategies are poorly evaluated to date and are usually adjuncts to surgery and reserved for limited disease.

Percutaneous cryoablation in combination with ethanol injection for unresectable hepatocellular carcinoma

AIM: To evaluate the effectiveness and safety of percutaneous hepatic cryoablation in combination with percutaneous ethanol injection (PEI) in patients with unresectable hepaocellular carcinoma (HCC).

METHODS: A total of 105 masses in 65 HCC patients underwent percutaneous hepatic cryoablation. The cryoablation was performed with the Cryocare system (Endocare, Irvine, CA, USA) using argon gas as a cryogen. Two freeze-thaw cycles were performed, each reaching a temperature of -180 °C at the tip of the probe. PEI was given in 36 patients with tumor masses larger than 6 cm in diameter 1-2 weeks after cryoablation and then once per week for 4 to 6 sessions. The efficacy was evaluated with survival, change of tumor size and alpha-fetoprotein (AFP) levels.

RESULTS: During a follow-up duration of 14 months in average with a range of 5 to 21 months, 33 patients (50.8%) were free of tumors, 22 patients (33.8%) alive with tumor recurrence: two had bone metastases, three were found to have lung metastases, and the remaining 17 recurrences occurred in the liver, of whom only 3 developed a cryosite recurrence. Among the 41 patients who were followed up for more than one year, 32(78%) were alive despite of tumor recurrence. Seven patients (10.8%) died due to disease recurrence. Three patients (4.6%) died due to some noncancer-related causes. Among the 43 patients who had a CT scan available for review, 38 (88.4%) had a shrinkage of tumor mass. Among the 22 patients who received biopsies of cryoablated tumor mass, all biopsies except one, showed only dead or scar tissues. Of the patients who had an increased AFP preablatively, 91.3% had a decrease of AFP to normal or nearly normal levels during postablative 3-6 months. Complications of cryoablation included liver capsular cracking in one patient,transient thrombocytopenia in 4 patients and asymptomatic right-sided pleural effusions in 2 patients. Two patients developed liver abscess at the previous cryoablation site at 2 and 4 months, respectively, following cryoablation, and was recovered after treated with antibiotics and drainage.

CONCLUSION: Percutaneous cryoablation offers a safe and possibly curative treatment option for patients with HCC that cannot be surgically removed, and its integration with PEI, may serve as an alternative to partial liver resection in selective patients.

Effects of liquid nitrogen treatment on the proliferation of osteosarcoma and the biomechanical properties of normal bone

To overcome problems of autografts for reconstruction in the presence of malignant bone and soft tissue tumors, we devised a method for treating autografts that utilizes the hypothermic effect of liquid nitrogen. We measured temperature changes inside the bone at each condition and established a one-cycle liquid nitrogen protocol that included 20 min in liquid nitrogen, 15 min in room air, and 15 min in physiological saline. The proliferation potential of the tumor cells treated with the liquid nitrogen method was examined by means of bromodeoxyuridine (BrdU) immunostaining. Tumor proliferation potential in vivo was examined in nude mice. Based on the results we concluded that the tumor cells died out as a result of the liquid nitrogen method. Regarding compression strength there was no significant difference between intact bone and liquid nitrogen-treated bone, whereas the strength of the autoclaved bone was decreased. Scanning electron microscopic examination of the fracture surface of the autoclaved bone after the compression test showed an irregular, uneven surface, whereas that of the liquid nitrogen-treated bone was smooth and fine-grained. This might be one of the reasons for the discrepancy in compression strength.

Strategies to increase the resectability of liver metastases from colorectal cancer

Liver resection can provide long-term survival and cure for patients with colorectal liver metastases but is feasible in only 15-25% of patients. In the last few years several major developments have contributed to increase this resectability rate. Neo-adjuvant chemotherapy can provide response rates as high as 50%, allowing surgery in about 10-15% of patients initially deemed unresectable. Patients requiring extensive liver resections with an anticipated small residual liver volume can undergo portal vein embolization to reduce the risk of postoperative liver failure by inducing hypertrophy of the remnant liver. Extensive bilobar disease can be treated by two-stage hepatectomy, with an interval to allow liver regeneration. Ablation techniques can be combined with hepatic resection to reduce local recurrence from incomplete surgical resection margins or to destroy contralateral tumor deposits. Finally, for patients with tumors involving the inferior vena cava or the hepatic veins, in which conventional resection is not feasible, in situ hypothermia or bench resection with reimplantation are suitable for very selected patients. Downstaging strategies may increase the resectability rate of colorectal liver metastases by over 20%.

Cryosurgery in long bones with new miniature cryoprobe: an experimental in vivo study of the cryosurgical temperature field in sheep

AIM

The aim of this in vivo study was to determine whether new miniature cryoprobes provide adequate tissue cooling in long bones by measuring the field of temperature under various conditions.

METHODS

Freezings were performed in femoral and tibial bones of 10 sheep under general anaesthesia. Applying one cryoprobe, temperatures of -75 degrees C resp. -51 degrees C could be reached within 0.75 cm resp. 1.00 cm of the probe.

RESULTS

Histological examinations revealed compact bone and marrow necroses along the isotherm in all 10 sheep. Using two cryoprobes simultaneously, a mean temperature decrease to -71 degrees C between the two cryoprobes was achieved thanks to the synergistic freezing effect. Looking at consecutive freezes, it was apparent that with similar cryoprobe end temperatures, the temperature dropped faster if the number of freezing cycles was increased.

CONCLUSION

In conclusion, it was seen that despite its small diameter, the new miniature cryoprobe delivers adequate in vivo tissue cooling in long tubular bones. Employing the synergistic freezing effect by using two or more cryoprobes simultaneously, efficient in vivo freezing of larger bone segments is also possible. Thus, cryosurgery with the new miniature probes can provide a valuable complement to conventional resection of long tubular bones, and offers a viable alternative to surgical treatment of neoplastic diseases of the skeletal system.

Multi-organ inflammation after hepatic cryoablation in BALB/c mice

BACKGROUND

There is increasing evidence that injury to the liver can precipitate or exaggerate lung injury. We have previously shown that hepatic cryoablation (cryo) causes activation of nuclear factor (NF)-kappaB, cytokinemia (tumor necrosis factor-alpha, Mouse Macrophage Inflammatory Protein-2 [MIP-2]), and lung inflammation in transgenic HLL (5'HIV-LTR-Luciferase gene) mice and in Sprague-Dawley rats. It has been reported that BALB/c mice are susceptible to traumatic injury and are active immune responders. We tested whether activation of NF-kappaB and the development of multiple-organ inflammation in response to hepatic injury from 35% cryo were demonstrable in the BALB/c mouse.

METHODS

BALB/c mice (n = 9) were anesthetized, and midline laparotomy was performed. Cryoablation was performed with careful isolation of adjacent structures to avoid inadvertent organ injury to the gastrointestinal tract. A freeze-thaw cycle of the left lobe of the liver was induced, encompassing approximately 35% (by weight). Animals were sacrificed at 1, 2, 4, and 24 h after cryoablation. Serum was collected via IVC puncture and liver, lungs, and kidneys were harvested and freeze-clamped. Two animals were sacrificed without undergoing cryo surgery to serve as a baseline control. NF-kappaB activity was monitored by electrophoretic mobility shift assays. MIP-2 levels and Mouse KC levels from tissue and serum were measured using enzyme-linked immunosorbent assay. Organs were submitted for histological review. We characterized lung inflammation induced by cryosurgery by measuring total and differential cell counts in lung lavage fluid 4 h after hepatic cryoablation.

RESULTS

After cryo, NF-kappaB activation was demonstrated in the 1, 2, and 4-h time points by electrophoretic mobility shift assay in the liver and lungs. Mouse KC and MIP-2 levels increased from baseline, peaked at the 4-h time point, and returned to baseline after 24 h in both liver and lung. Lung lavage 4 h after cryoablation showed increased total cells and neutrophilic lung inflammation.

CONCLUSIONS

BALB/c mice demonstrate evidence of multi-organ inflammation in response to 35% hepatic cryo. These data demonstrate that this model provides for assessment of liver-mediated multi-system inflammation after direct liver injury.

Thermal ablative therapy for malignant liver tumors: a critical appraisal

The management of primary and secondary malignant liver tumors poses a great challenge to clinicians. Although surgical resection is the gold-standard treatment, most patients have unresectable malignant liver tumors. Over the past decade, various modalities of loco-regional therapy have gained much interest. Among them, thermal ablative therapy, including cryotherapy, microwave coagulation, interstitial laser therapy, and radiofrequency ablation (RFA), have been proven to be safe and effective. Despite the effective tumor eradication achieved within cryotherapy, the underlying freeze/thaw mechanism has resulted in serious complications that include bleeding from liver cracking and the 'cryoshock' phenomenon. Thermal ablation using microwave and laser therapy for malignant liver tumors is curative and is associated with minimal complications. However, this treatment modality is effective only for tumors <3 cm diameter. Radiofrequency ablation seems to be the most promising form of thermal ablative therapy in terms of a lower complication rate and a larger volume of ablation. However, its use is restricted by the difficulty encountered when using imaging studies to monitor the areas of ablation during and after the procedure. Moreover, the techniques of RFA need to be refined in order to achieve the same oncological radicality of malignant liver tumors as achieved by surgical resection. As each of the loco-regional therapies has its own advantages and limitations, a multidisciplinary approach using a combination of therapies will be the future trend for the management of malignant liver tumors.