Cryoablation of unresectable malignant liver tumors

Interstitial ablative techniques for hepatic tumours

BACKGROUND

Most patients with liver tumours are not suitable for surgery but interstitial ablative techniques may control disease progression and improve survival rates.

METHODS

A review was undertaken using Medline of all reported studies of cryoablation, radiofrequency ablation, microwave ablation, interstitial laser photocoagulation, high-intensity focused ultrasound and ethanol ablation of primary liver tumours and hepatic metastases.

RESULTS

Although there are no randomized clinical trials, cryoablation, thermal ablation and ethanol ablation have all been shown to be associated with improved palliation in patients with primary and secondary liver cancer. The techniques can be undertaken safely with minimal morbidity and mortality.

CONCLUSION

Although surgical resection remains the first line of treatment for selected patients with primary and secondary liver malignancies, interstitial ablative techniques are promising therapies for patients not suitable for hepatic resection or as an adjunct to liver surgery.

Colorectal cancer in 2003: old principles, new strategies

In the last two decades the prognosis of colorectal cancer has improved for two reasons: (i) the proportion of patients with localized disease has increased and treatment has been standardized, and (ii) new chemotherapeutic agents have led to a longer life expectancy for patients with advanced disease. In this review the current insights in disease etiology and treatment of localized and disseminated colorectal cancer are discussed.

Adrenal-preserving minimally invasive surgery: the role of laparoscopic partial adrenalectomy, cryosurgery, and radiofrequency ablation of the adrenal gland

Adrenalectomy has become the standard of care for the management of hormonally active adrenal masses. Various surgical therapies have been proposed to excise completely or destroy these adrenal lesions, which may be benign or malignant. New minimally invasive, adrenal-sparing procedures have recently been introduced, among them laparoscopic partial adrenalectomy, cryosurgery, and radiofrequency ablation. These procedures focus on reducing patient morbidity and hastening postoperative recovery while preserving normal adrenal tissue. However, questions remain about the risks and benefits associated with routine application of minimally invasive therapies for adrenal-sparing surgery in terms of complete tumor extirpation. Clearly, more experience and longer follow-up is necessary to validate these procedures. Herein we describe the surgical techniques and early results of treatment with adrenal-sparing surgery.

Pro- and antiinflammatory cytokine production after radiofrequency ablation of unresectable hepatic tumors

BACKGROUND

Experience using radiofrequency ablation (RFA) for treating unresectable hepatic malignancies is expanding, with promising outcomes and fewer complications compared with cryotherapy.

STUDY DESIGN

This study examined systemic inflammatory responses after RFA as measured by the appearance of postoperative symptoms and cytokine production. Seventeen patients (11 men, 6 women) aged 40 to 85 years (mean 64.2 years) with unresectable primary and metastatic hepatic tumors underwent RFA. Mean liver volume treated with RFA was 35.3% +/- 3.6% (SEM) (median 36.8%). Plasma cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-1ra, IL-6, IL-8, IL-10, p55, and p75) were measured from anesthesia induction through 48 hours after RFA. Ex vivo whole-blood cytokine production was measured at baseline, 24 hours, and 48 hours after RFA.

RESULTS

Cytokine and cytokine-receptor production were not notably altered by RFA. Ex vivo whole-blood endotoxin stimulation indicated that intrinsic cellular immune function remained intact after treatment, although modest decreases in stimulated tumor necrosis factor alpha production were observed 24 to 48 hours after RFA. Variceal bleeding, hepatic failure, and death occurred in one patient 30 days after RFA. None of the remaining patients exhibited tachycardia or hypotension. Fevers (> or = 38.5 degrees C) developed in three patients during the first 48 hours postoperatively. There was no association between plasma cytokines and postoperative complications.

CONCLUSIONS

In contrast to previous reports using cryotherapy, systemic inflammatory responses as measured by increased cytokines were not observed after RFA. The cryotherapy-induced "cryoshock" phenomenon was not observed in patients undergoing RFA in our study. We conclude that RFA ablation is fundamentally different than cryotherapy and apparently does not stimulate Kupffer and other hepatic macrophages to produce proinflammatory cytokines.

Cryotherapeutic ablation of liver tumours

BACKGROUND

This paper reports a 7-year experience of cryoablation for colorectal and non-colorectal liver metastases.

METHODS

A retrospective review was undertaken of patients treated in two adjacent UK centres in the north-west of England.

RESULTS

Over a 7-year period (1993-2000), 57 patients underwent cryotherapy for malignant hepatic tumours (41 colorectal, 16 non-colorectal). In the patients with colorectal metastases, preoperative carcinoembryonic antigen (CEA) levels fell significantly, from a mean of 444.1 to 6.22 micro g/l (P = 0.002). One patient died, two developed cryoshock and six had cardiorespiratory complications. All patients with colorectal metastases subsequently received 5-fluorouracil-based chemotherapy. The remaining 16 patients with non-colorectal tumours (seven neuroendocrine metastases, five hepatocellular carcinomas, three sarcomas, one cholangiocarcinoma) all received cryotherapy alone, with no major complications. The median survival for patients with non-colorectal metastases was 37 months, compared with 22 months for those with colorectal metastases (P = 0.005).

CONCLUSION

Hepatic cryotherapy is effective and safe, as demonstrated by the significant reduction in postoperative CEA concentration and the low risk of complications. However, this initial short-term success was not reflected in 5-year survival rates. Cryotherapy for non-colorectal metastases had a greater long-term survival benefit and is a useful means of controlling symptoms.

Large volume hepatic freezing: association with significant release of the cytokines interleukin-6 and tumor necrosis factor a in a rat model

Although cryotherapy of liver tumors is generally considered a safe procedure, a syndrome of coagulopathy and fatal multiorgan failure has been observed in some patients and is called the cryoshock phenomenon. Our aim was to establish an animal model of this phenomenon and examine the effects of the basic parameters of freezing or cryotherapy on it. A group of 75 female Sprague-Dawley rats were allocated randomly to five groups: (1) sham laparotomy (n = 15); (2) small (25% liver volume) single freeze (n = 15); (3) small (25% liver volume) double freeze (n = 15); (4) large (50% liver volume) single freeze (n = 15); (5) large (50% liver volume) double freeze (n = 15). Blood samples were collected at different postoperative times, and organs were harvested for histopathology. There was a significant release of tumor necrosis factor-a (TNFa) and interleukin 6 (IL-6) following hepatic freezing, which was greatest in group 5. Postoperative serum cytokine levels were significantly associated with hepatocellular injury, as measured by postoperative serum aspartate transaminase (AST) concentrations. Severe hemoglobinuria and renal injury, as demonstrated by the serum creatinine level and the glomerular neutrophil count, were observed and were greatest in group 5. Hepatic cryosurgery is associated with release of IL-6 and TNFa and renal injury in a rat model. It is likely that the cryoshock phenomenon is another form of the systemic inflammatory response syndrome. Based on the results of this study, it is possibly mediated by cytokines released from the frozen liver tissue. We therefore caution against cryotherapy of large tumor volumes.

Treatment of liver metastases, an update on the possibilities and results

Long-term results after liver resection for colorectal liver metastases show 5-year survival rates between 35 and 40%. However, only a limited number of patients appear to be candidates for resection, far more patients prove to have unresectable disease. Present challenges in liver surgery for colorectal metastases are to improve patient selection, to increase the resectability rate and to improve survival by multimodality treatment approaches. The variables most consistently associated with a poor prognosis and tumour recurrence are tumour-positive resection margins and the presence of extra-hepatic disease. Hence, patient selection and preoperative staging should concentrate on accurate imaging of the liver lesions and the detection of extrahepatic disease. For liver imaging, spiral computed tomography (CT) scan or magnetic resonance imaging (MRI), supplemented by intra-operative ultrasound, are currently regarded as the best methods for evaluating the anatomy and resectability of colorectal liver metastases. Extrahepatic disease should be investigated by spiral CT of the chest and abdomen and when possible by 2-fluouro-2-deoxy-D-glucose-positron emission tomography (FDG-PET). Resection remains the gold standard for the surgical treatment of colorectal liver metastases. In experienced centres, resection is a safe procedure and mortality rates are below 5%. The aim of resection should be to obtain tumour-negative resection margins. Edge cryosurgery should be considered in cases where very close resection margins are anticipated. The role of adjuvant chemotherapy after resection is still controversial, although two recent studies show a clear benefit. For the moment, local tumour ablative therapies such as cryotherapy and radiofrequency therapy should be considered as an adjunct to hepatic resection in those cases in which resection can not deal with all of the tumour lesions. In these cases, there seems a beneficial effect of a combined treatment consisting of resection and local tumour ablation. At this stage, there are no randomised data that local tumour ablation is as effective as resection. For a selected group of patients with unresectable liver metastases, there may be a chance to turn unresectable disease to resectable disease by aggressive neo-adjuvant chemotherapy or portal vein embolisation. For patients with unresectable disease, many different chemotherapy schedules may be used based on systemic drug administration. Regional chemotherapy and isolated liver perfusion should only be used within a study design.

Resection and local therapy for liver metastases

In 30-50% of patients the liver is a preferred site of distant disease for many malignant tumours. Due to the high incidence, most of the available data relate to metastases arising from colorectal primaries. Surgical resection is at present the only treatment offering potential cure. The achievable 5-year survival rate is 30%. However, only 10-15% of patients with colorectal liver metastases can undergo potentially curative liver resection. Therefore, accurate staging is an important prerequisite in selecting patients who would benefit from surgery. Recurrence of hepatic metastases after potentially curative resection occurs in up to 60% of the cases. Results demonstrate that re-resection of liver metastases can provide long-term survival rates in a carefully selected group of patients without extrahepatic disease. Because of the high rate of recurrences following an apparently curative resection several authors investigated the use of adjuvant chemotherapy (systemic, intraportal, and hepatic arterial infusion). Until recently none had shown effectiveness. Pre-operative chemotherapy seems to be a promising approach in patients with liver metastases initially considered unsuitable for radical surgery. Recently, neoadjuvant chemotherapy has been proposed as an alternative approach to conventional surgery as initial management with the aim of improving the results in resectable liver metastases. Interventional strategies (ethanol injection, cryosurgery, laser-induced thermotherapy, radio-frequency ablation) and combined modalities (surgical/interventional) are additive methods which may help to improve treatment results in the future.

Cryotherapy in the treatment of liver metastases from colorectal cancer

Although hepatic resection remains the treatment of choice for metastatic disease to the liver from colorectal cancer, the procedure is only possible for approximately 10% of patients. Ninety percent of patients with liver metastases ultimately die of liver failure. Thus, attention has turned to other, locoregional techniques that may be used alone or in conjunction with resection to increase the eligibility for some type of surgical, potentially curative treatment. One such option is cryotherapy. This review provides technical, physiologic, and outcome information regarding this technique. Semin Oncol 29:183-191.

Alternative techniques for the treatment of colon carcinoma metastases in the liver: current status in The Netherlands

BACKGROUND

Review of current treatment modalities for liver metastases resulting from colorectal cancer.

METHODS

Literature review.

RESULTS

An increasing number of techniques are available for the treatment of colorectal liver metastases. When it is not possible to use the current gold standard, radical surgical resection, many patients can be treated with alternative techniques. Chemotherapy in its present form must be considered as purely palliative, perhaps with the exclusion of isolated liver perfusion: however, this therapy should still be considered as experimental. Most other possible treatments focus on local destruction of the metastases. This can be achieved using either immuno-guided techniques (tumor antibodies which carry a local active agent), direct local application of a toxic agent (injection) or thermo therapy, which has been applied in patients on a large scale. Thermo therapy involves either localized heating, by means or laser photocoagulation or radiofrequency or microwave ablation, or localized freezing using cryo probes.

CONCLUSIONS

Local destruction of liver metastases, especially by means of thermo therapy, is feasible and safe. Currently, cryotherapy is most frequently used in patients. New treatment modalities, such as radiofrequency ablation, arc very promising but their true clinical value should be determined in a randomized clinical trial.

Usefulness of intraoperative sonography for revealing hepatic metastases from colorectal cancer in patients selected for surgery after undergoing FDG PET

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of preoperative positron emission tomography (PET) with FDG and intraoperative sonography with the standard of histologic examination of resected liver specimens in evaluating patients for curative resection of liver metastases from colorectal cancer.

MATERIALS AND METHODS

We retrospectively identified 47 patients with recurrent colorectal cancer who underwent surgical exploration for possible curative resection of hepatic metastases. All patients underwent CT or MR imaging and FDG PET preoperatively and intraoperative sonography. The performance of the imaging techniques was evaluated through review of the radiologic reports and correlation with surgical and histopathologic findings.

RESULTS

Eighty-seven malignant hepatic lesions were identified by histopathologic analysis of liver specimens, and 23 benign hepatic abnormalities were documented histopathologically or by uroradiologic imaging. For hepatic sections characterized as containing metastases by radiologic imaging, the positive predictive value for FDG PET was 93% (54/58); for intraoperative sonography, 87% (52/60); and for conventional imaging, 83% (43/52). For individual lesions characterized as probably malignant, the positive predictive value for FDG PET was 93% (62/68); for intraoperative sonography, 89% (63/71); and for conventional imaging, 78% (46/59). The findings at intraoperative sonography led to a change in the clinical treatment of only one patient (2%).

CONCLUSION

The results indicate that FDG PET effectively screens potential candidates for curative liver resection. Although intraoperative sonography helps to determine the anatomic location of metastases thus facilitating surgical resection, its adjunctive use in patients screened preoperatively by FDG PET has limited impact on treatment selection.

Diagnostic, surgical and medical aspect of the midgut carcinoids

This review covers the incidence, prognosis, diagnosis and treatment of midgut carcinoids with emphasis on the surgical and peri-operative aspects. Midgut carcinoids are rare neuro-endocrine tumours which become manifest once they have metastasized to the liver. Treatment of metastatic disease may include radical resection but is usually palliative. The tumour grows relatively slow. Besides the biochemical effects resulting in the carcinoid syndrome, patients may suffer from mechanical mass effects of the tumour. Medical treatment can alleviate the biochemical effects of the tumour, but has a limited effect on tumour growth. The introduction of octreotide was a milestone in palliation of these symptoms and has led to more aggressive treatment protocols. Treatment aimed at cytoreduction of hepatic metastasis and diminished secretion of bioactive amines may achieve good palliation. Cytoreduction may be performed by means of surgery, hepatic arterial ligation, (chemo)embolization, cryosurgery, radio-frequency ablation, internal radiation or even liver transplantation. The role of these options will be discussed in this review.

[Cryosurgery of primary and metastatic cancers of the liver]

Cryosurgery is a method of in situ destruction of tissue by a freezing process. Results of hepatic cryosurgery are now available for more than 2100 patients and allow to assess its place in the treatment of hepatic malignancies. Mechanisms of tissue destruction and indications of cryosurgery are detailed. With a peri-operative mortality rate of 1.5%, the safety of hepatic cryosurgery is now admitted. Cryosurgery has its own morbidity: increase of transaminases levels, platelets drop, myoglobinuria and rarely renal failure or cryoshock. In selected patients, hepatic cryosurgery is feasible with a laparoscopic or percutaneous approach. Long term results do not support cryosurgery as an alternative to liver resection. This technique enlarges possibilities of surgical treatment for patients with primary and metastatic liver cancers.

Gastrinoma

Gastrinoma treatment has evolved considerably in the last 20 years. In particular, the advent of effective acid-reducing pharmacologic agents has changed the primary morbidity of this disease entity from one of acid hypersecretion to one of tumor growth and spread. Thus, while symptoms can be temporized using histamine receptor antagonists, proton pump inhibitors, or somatostatin analogs, cure can be effected only by surgical means. Recent advances in operative techniques and pre- and intra-operative imaging studies, including routine duodenotomy, somatostatin-receptor scintigraphy, and intraoperative ultrasound, have allowed for identification and subsequent resection of more than 95% of gastrinoma tumors. Most experts agree that all sporadic cases of localized gastrinoma should be excised. In addition, debulking of metastatic tumor may improve symptoms and survival when cure cannot be ascertained. There is, however, some controversy as to the surgical approach for gastrinoma found in the setting of multiple endocrine neoplasia, type 1. Because of the usual multiplicity and particular indolence of these tumors, two primary strategies have emerged: aggressive approaches have been advocated in an effort to eradicate all present and potential tumor; and less aggressive, or nonoperative, approaches have been suggested because it is unclear whether intervention offers survival or disease-free benefit in this population. We advocate surgical intervention for patients with gastrinoma and multiple endocrine neoplasia, type 1 when tumors exceed 2.5 cm in size. This tumor size has been associated with a higher likelihood of hepatic metastases, which ultimately affects survival. The role of adjuvant therapies for gastrinoma remains limited.

Long-term results of treating hepatic colorectal metastases with cryosurgery

BACKGROUND

The purpose of this study was to determine the long-term efficacy of cryosurgery as an adjunct to hepatic resection in patients with colorectal liver metastases not amenable to resection alone.

METHODS

Thirty patients met the following inclusion criteria: metastases confined to the liver and judged irresectable, ten or fewer metastases, cryosurgery alone or in combination with hepatic resection allowed tumour clearance.

RESULTS

Median follow-up was 26 (range 9--73) months. Overall 1- and 2-year survival rates were 76 and 61 per cent respectively. Median survival was 32 months. Disease-free survival at 1 year was 35 per cent, at 2 years 7 per cent. Six patients developed recurrence at the site of cryosurgery; given that the total number of cryosurgery-treated lesions was 69 the local recurrence rate was 9 per cent.

CONCLUSION

In patients with colorectal liver metastases, local ablative techniques can be used as an effective adjunct to hepatic resection to obtain tumour clearance.

Impact of intraoperative sonography on resection and cryoablation of liver tumors

PURPOSE

We retrospectively analyzed the impact of intraoperative sonography (IOUS) on the management of patients referred for resection of liver tumors.

METHODS

Forty patients underwent IOUS with a 7-MHz curved-array sector transducer; in selected cases, a 5-MHz linear-array transducer attached to a color Doppler unit was also used. The number, size, and location of tumors on IOUS, including tumor proximity to or invasion of major vessels or invasion of the diaphragm, were compared to findings on preoperative imaging studies. The effect of these findings on surgical management was assessed. Unresectable lesions were treated by cryoablation under ultrasound guidance.

RESULTS

IOUS detected preoperatively unsuspected lesions in 7 patients (18%). Metastases suspected on CT arterial portography were ruled out in 2 patients (5%), and indeterminate lesions were diagnosed as cysts by IOUS in 2 other patients (5%). Vascular proximity or vascular or diaphragmatic invasion detected by IOUS rendered lesions unresectable in 4 patients (10%). Cryoablation under IOUS guidance and monitoring was attempted in 11 patients (28%) and performed successfully in 10.

CONCLUSIONS

IOUS changed the management in 38% of patients and guided cryoablation in 28% of patients. IOUS performed by an experienced sonologist is invaluable for the accurate assessment of liver tumor resectability; the detection of additional, preoperatively unknown lesions; and the guidance of cryoablation of unresectable tumors.

Radiofrequency ablation of malignant liver tumors

The majority of patients with primary or metastatic hepatic tumors are not candidates for resection because of tumor size, location near major intrahepatic blood vessels precluding a margin-negative resection, multifocality, or inadequate hepatic function related to coexistent cirrhosis. Radiofrequency ablation (RFA) is an evolving technology being used to treat patients with unresectable primary and metastatic hepatic cancers. RFA produces coagulative necrosis of tumor through local tissue heating. Liver tumors are treated percutaneously, laparoscopically, or during laparotomy using ultrasonography to identify tumors and guide placement of the RFA needle electrode. For tumors smaller than 2.0 cm in diameter, one or two deployments of the monopolar multiple array needle electrode are sufficient to produce complete coagulative necrosis of the tumor. However, with increasing size of the tumor, there is a concomitant increase in the number of deployments of the needle electrode and the overall time necessary to produce complete coagulative necrosis of the tumor. In general, RFA is a safe, well-tolerated, effective treatment for unresectable hepatic malignancies less than 6.0 cm in diameter. Effective treatment of larger tumors awaits the development of more powerful, larger array monopolar and bipolar RFA technologies.

Laparoscopic cryoablation of a metastatic carcinoid tumor

Carcinoid tumors are rare, slow-growing neuroendocrine neoplasms that can cause a carcinoid syndrome. The majority of carcinoid syndromes are the result of multiple hepatic metastases and are usually unresectable. Medical therapy has not proven effective and often causes intolerable side effects. Cryoablation has emerged as a promising treatment for various hepatic lesions when resection is not an option and medical therapy has been exhausted. With the addition of laparoscopy, surgeons now possess a new technique to treat primary and various secondary liver lesions. We report for the first time laparoscopic cryoablation for the treatment of a carcinoid metastatic to the liver.

Hepatic cryoablation-induced acute lung injury: histopathologic findings

We have previously shown that hepatic cryoablation (cryo), but not partial hepatectomy, induces a systemic inflammatory response, with distant organ injury and overproduction of NF-kappaB-dependent cytokines. Serum tumor necrosis factor-alpha (TNF-alpha) and macrophage inflammatory protein-2 (MIP-2) levels are markedly increased 1 h and beyond after cryo compared with partial hepatectomy where no elevation occurs. NF-kappaB activation (by electrophoretic mobility shift assay) is strikingly increased in the noncryo liver (but not in the lung) at 30 min and in both the liver and lung tissue 1 h after cryo, returning to the baseline by 2 h and beyond. The current study investigated the histopathologic changes associated with cryoablation-induced acute lung injury. Animals underwent 35% hepatic resection or a similar volume hepatic cryo and were sacrificed at 1, 2, 6, and 24 h. Pulmonary histologic features were assessed using hematoxylin and eosin and immunoperoxidase staining with a macrophage-specific antibody (anti-lysozyme, 1:200 dilution, Dako, Carpinteria, CA). The following features were graded semiquantitatively (0-3): perivascular lymphoid cuffs, airspace edema and hemorrhage, margination of neutrophils within pulmonary vasculature, and the presence of macrophages with foamy cytoplasm in the pulmonary interstitium. Hepatic resection (n = 21) resulted in slight perivascular edema at 1, 2, 6, and 24 h post-resection, but there were no other significant changes. Pulmonary findings after hepatic cryo (n = 22) included prominent perivascular lymphoid cuffs 1 and 2 h following hepatic injury that were not present at any other time point (P 0.01). Marginating PMNs and foamy macrophages were more common after cryo at all time points (P<0.05, cryo vs resection). Severe lung injury, as evidenced by airspace edema and parenchymal hemorrhage, was present in four of six (67%) animals at 24 h (P 0.03). In follow-up studies immediate resection (n = 15) of the cryo-treated liver prior to thawing prevented the pulmonary changes. The findings of pulmonary perivascular interstitial macrophages 2 h following hepatic cryo suggests that hepatic cytokine production may induce downstream recruitment of pulmonary macrophages, which may contribute to subsequent severe lung injury. This study suggests that a soluble mediator from direct liver injury leads to neutrophilic lung inflammation and this is associated with the thawing phase of cryoablation.

Comparison of iceball diameter and temperature distribution achieved with 3-mm accuprobe cryoprobes in porcine and human liver tissue and human colorectal liver metastases in vitro

We aimed to assess the thermal profile and size of iceballs produced by Accuprobe cryoprobes in fresh porcine and human liver and human colorectal cancer liver metastases in vitro to allow better planning of cryosurgical treatment of liver metastases. Iceballs were produced by a 20-min single freeze cycle using 8-mm cryoprobes in pig liver in a waterbath at 37 degrees C (n = 8) and 3-mm cryoprobes in pig liver (n = 8), human liver (n = 3), and human colorectal cancer liver metastases (n = 8). The iceball diameters and the temperatures at different distances from the cryoprobe were measured. Mean iceball diameters produced by 8-mm cryoprobes in pig liver were 56.3 mm and varied from 38.7 to 39.6 mm for 3-mm cryoprobes in the different tissues used. There was no significant difference in iceball size in the different tissues. The diameter of the zone of -40 degrees C or less was approximately 44 mm using 8-mm cryoprobes in porcine liver and between 27 and 31 mm using 3-mm cryoprobes in the different tissues examined. The results may allow better preoperative planning of the cryosurgical treatment of liver metastases with Accuprobe cryoprobes.

Cryohemostasis of uncontrolled hemorrhage from liver injury

Uncontrolled hemorrhage is the primary cause of death in both blunt and penetrating liver trauma. Cryohemostasis was attempted in the past for elective liver surgery but did not gain popularity. During past decades, cryoequipment was refined and successfully used for tumor ablation. The purpose of the present study was to assess the efficacy of cryosurgery as a potential adjuvant hemostatic technique in the treatment of grades III-IV liver injuries. A standard liver crush-evulsion injury was created in pigs. In the control group, the liver was left to bleed freely. In the experimental group, the severed liver surface was immediately frozen to -160 degrees C for 10 min, spontaneously thawed, and left to bleed thereafter. Blood pressure, pulse rate, urine output, and serum lactate were monitored. The total blood loss was measured 180 min after liver injury was inflicted. The volume of frozen liver parenchyma was measured. For further laboratory evaluation, three additional experimental animals were not sacrificed and recovered. Cryohemostasis significantly reduced blood loss and substantially attenuated hemorrhagic shock. The frozen liver parenchyma underwent necrosis but did not jeopardize survival. Cryosurgery may be an efficient adjuvant technique in the early control of hemorrhage in grades III-IV liver injury.

Hepatic cryoablation, but not radiofrequency ablation, results in lung inflammation

OBJECTIVE

To compare the effects of 35% hepatic cryoablation with a similar degree of radiofrequency ablation (RFA) on lung inflammation, nuclear factor kappaB (NF-kappaB) activation, and production of NF-kappaB dependent cytokines.

SUMMARY BACKGROUND DATA

Multisystem injury, including acute lung injury, is a severe complication associated with hepatic cryoablation of 30% to 35% or more of liver parenchyma, but this complication has not been reported with RFA.

METHODS

Sprague-Dawley rats underwent 35% hepatic cryoablation or RFA and were killed at 1, 2, and 6 hours. Liver and lung tissue were freeze-clamped for measurement of NF-kappaB activation, which was detected by electrophoretic mobility shift assay. Serum concentrations of tumor necrosis factor alpha and macrophage inflammatory protein 2 were measured by enzyme-linked immunosorbent assay. Histologic studies of pulmonary tissue and electron microscopy of ablated liver tissue were compared among treatment groups.

RESULTS

Histologic lung sections after cryoablation showed multiple foci of perivenular inflammation, with activated lymphocytes, foamy macrophages, and neutrophils. In animals undergoing RFA, inflammatory foci were not present. NF-kappaB activation was detected at 1 hour in both liver and lung tissue samples of animals undergoing cryoablation but not after RFA, and serum cytokine levels were significantly elevated in cryoablation versus RFA animals. Electron microscopy of cryoablation-treated liver tissue demonstrated disruption of the hepatocyte plasma membrane with extension of intact hepatocyte organelles into the space of Disse; RFA-treated liver tissue demonstrated coagulative destruction of hepatocyte organelles within an intact plasma membrane. To determine the stimulus for systemic inflammation, rats treated with cryoablation had either immediate resection of the ablated segment or delayed resection after a 15-minute thawing interval. Immediate resection of the cryoablated liver tissue prevented NF-kappaB activation and lung injury; however, pulmonary inflammatory changes were present when as little as a 15-minute thaw interval preceded hepatic resection.

CONCLUSIONS

Hepatic cryoablation, but not RFA, induces NF-kappaB activation in the nonablated liver and lung and is associated with acute lung injury. Lung inflammation is associated with the thawing phase of cryoablation and may be related to soluble mediator(s) released from the cryoablated tissue. These findings correlate the clinical observation of an increased incidence of multisystem injury, including adult respiratory distress syndrome (ARDS), after cryoablation but not RFA.

Localized hepatocellular carcinoma: therapeutic options

Hepatocellular carcinoma (HCC) is among the most common malignancies worldwide. Recent surveillance programs have allowed early detection and diagnosis, but overall survival of patients with HCC remains poor. This article provides a definition for localized HCC and summarizes the array of treatments that have emerged and the salient literature and findings for each. Among the treatments reviewed here are surgical resection, orthotopic liver transplantation, and local ablative therapies such as cryosurgery, percutaneous ethanol injection therapy, and transarterial chemoembolization.

Intraoperative radiofrequency ablation or cryoablation for hepatic malignancies

BACKGROUND

The majority of patients with primary or metastatic malignancies confined to the liver are not candidates for resection because of tumor size, location, multifocality, or inadequate functional hepatic reserve. Cryoablation has become a common treatment in select groups of these patients with unresectable liver tumors. However, hepatic cryoablation is associated with significant morbidity. Radiofrequency ablation (RFA) is a technique that destroys liver tumors in situ by localized application of heat to produce coagulative necrosis. In this study, we compared the complication and early local recurrence rates in patients with unresectable malignant liver tumors treated with either cryoablation or RFA.

PATIENTS AND METHODS

Patients with hepatic malignancies were entered into two consecutive prospective, nonrandomized trials. The liver tumors were treated intraoperatively with cryoablation or RFA; intraoperative ultrasonography was used to guide placement of cryoprobes or RFA needles. All patients were followed up postoperatively to assess complications, treatment response, and local recurrence of malignant disease.

RESULTS

Cryoablation was performed on 88 tumors in 54 patients, and RFA was used to treat 138 tumors in 92 patients. Treatment-related complications, including 1 postoperative death, occurred in 22 of the 54 patients treated with cryoablation (40.7% complication rate). In contrast, there were no treatment-related deaths and only 3 complications after RFA (3.3% complication rate, P<0.001). With a median follow-up of 15 months in both patient groups, tumor has recurred in 3 of 138 lesions treated with RFA (2.2%), versus 12 of 88 tumors treated with cryoablation (13.6%, P<0.01).

CONCLUSIONS

RFA is a safe, well-tolerated treatment for patients with unresectable hepatic malignancies. This study indicates that (1) complications occur much less frequently following RFA of liver tumors compared with cryoablation of liver tumors, and (2) early local tumor recurrence is infrequent following RFA.

Thyroid cryotherapy in an experimental rat model

In recent years cryotherapy has been more and more frequently used for the treatment of tumors of different organs. Until now, the use of cryotherapy for the treatment of thyroid lesions, as well as histopathologic changes in thyroid tissue after cryotherapy, has not been described. Nitrous oxide cryotherapy of one thyroid lobe in twenty 12-week male Wistar rats was performed. After 2 and 4 weeks, the cryotreated thyroid lobe and the second lobe along with a part of the trachea, esophagus, and the subhyoid muscles adhering to the thyroid were excised and assessed macro- and microscopically. The macroscopic evaluation, performed 2 and 4 weeks postcryotherapy, revealed atrophy of the cryotreated lobe in 4 and 3 rats, respectively, and reduction of the cryotreated lobe dimensions in 6 and 7 rats, respectively. In the specimens of the lobes excised 2 weeks following cryotherapy, examined microscopically, necrosis, granulomatous inflammation, hemorrhages, and hemosiderin deposits were found most often, whereas in the specimens of the lobe excised after 4 weeks lymphocytic inflammation and fibrosis were mainly observed. No microscopic changes were observed in the thyroid lobes that were not frozen or in the parathyroid glands located inside these lobes or extrathyroidally, either ipsilaterally or contralaterally to the cryotreated thyroid lobes. There was no microscopic damage to other tissues adjacent to the thyroid gland. No rat developed vocal cord dysfunction after cryotherapy and no significant changes in serum calcium level before and after cryotherapy were observed. The results obtained show that it is possible to cryoblate thyroid tissue without damaging the tissues adjacent to the thyroid, as well as to spare function of the recurrent laryngeal nerves and parathyroid glands.

Cryosurgery: Adjuvant Treatment at the Time of Resection of a Pelvic Recurrence in Rectal Cancer

We report a case in which cryosurgical ablation was used to treat recurrent rectal cancer. Several years after low anterior resection for rectal cancer, the patient was found to have a large pelvic recurrence with involvement of the presacral space. After resection of the pelvic mass, cryosurgery was applied to the presacral space, extending to the lateral pelvic wall and up to the sacral promontory. After a 24-month follow-up, the patient remains disease-free with a Karnofsky performance status of 100 per cent. Cryosurgery can be used as an adjuvant therapy at the time of resection to successfully treat a pelvic recurrence.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

Current treatment for colorectal cancer metastatic to the liver

Surgery is currently the only available treatment option which offers the potential for cure for patients with liver metastases from colorectal cancer. Of those who undergo a potentially curative operation for their primary tumour but subsequently recur, almost 80% will develop evidence of metastatic disease within the liver. Greater experience and improvements in technique in liver surgery, with an increasingly aggressive surgical approach to metastatic colorectal cancer to the liver, has resulted in prolonged disease-free survival with 5-year rates varying from 21% to 48%. In order to increase these numbers further and to treat patients not eligible for surgical therapy, new treatment modalities and strategies have been developed. This review presents an update of the current treatment for colorectal disease metastatic to the liver.

Should hepatomas be treated with hepatic resection or transplantation?

BACKGROUND

The aim of this collaborative study was to compare the long term results of hepatic resection (Hx) with those of orthotopic liver transplantation (OLTx) in large numbers of cirrhotic patients with hepatocellular carcinoma (HCC) and to delineate the roles of these two surgical treatments.

METHODS

The databases of the National Cancer Center Hospital in Japan and the University of Pittsburgh Medical Center in the U. S. were exchanged and 294 cirrhotic patients who underwent curative Hx and 270 cirrhotic patients who underwent curative OLTx were selected for comparison.

RESULTS

The mortality rate within 30 days and that within 150 days after Hx were significantly lower than those after OLTx (P = 0.001 and P = 0.00007, respectively). Overall survival was similar between the Hx group and the OLTx group (P = 0.40). When compared in the HCC patients without macroscopic vascular invasion and lymph node metastases, the overall survival rate after OLTx was significantly higher than that after Hx (P = 0.006). However, this difference was not significant between the patients with Child-Pugh Grade A tumors in the Hx group and all patients (majority with Child-Pugh Grade C tumors) in the OLTx group (P = 0.25). Tumor free survival after OLTx was significantly higher than that after Hx (P < 0.0001), particularly in HCCs measuring </=5 cm, unilobarly distributed tumors, and HCCs with either no or only microscopic vascular invasion. In HCCs measuring > 5 cm and those with macroscopic vascular invasion, the tumor free survival rate was similar between the Hx group and the OLTx group.

CONCLUSIONS

In the face of organ shortage, HCC developing in a well compensated cirrhotic liver initially may be treated with Hx. However, the authors believe OLTx should be applied selectively to those patients with tumor recurrence and/or progressive hepatic failure.

Acute and chronic interstitial cryotherapy of the adrenal gland as a treatment modality

BACKGROUND AND OBJECTIVES

Adrenalectomy is indicated for patients with large adrenal lesions or functional tumors. Cryoablation is currently used as a surgical alternative for the treatment of prostate, lung, brain, pharynx, and liver tumors. The purpose of this study was to determine if cryosurgery could be delivered to small areas in the adrenal gland in a controllable and reproducible manner, so that tissue could heal in a nonpathological way.

MATERIALS AND METHODS

Fourteen female mongrel dogs underwent acute (N = 8) or chronic (4 weeks) (N = 6) cryoablation using the Cryounit. In the acute study, using an open transabdominal approach, a 2-mm cryoprobe was placed interstitially into the adrenal tissue, while 0.032-inch thermocouples were cannulated into the ipsilateral adrenal artery and vein. Adrenal parenchymal temperature changes were measured using thermocouples placed at 0.4- and 0.8-cm intervals from the cryoprobe. In the chronic study, cryoablation was achieved by transperitoneal laparoscopic access using standard laparoscopic technique.

RESULTS

Interstitial cryoprobe temperatures decreased from 33.1 +/- 1.9 degrees C to -148 +/- 1.2 degrees C following 15 minutes of freezing in the acute study. Cryoablation of adrenal tissue achieved temperatures of -41.8 +/- 5.7 degrees C and -21.8 +/- 1 degrees C at distances of 0.4 and 0.8 cm from the cryoprobe, respectively. There were no significant changes in adrenal artery or vein temperatures during cryoablation. Histologically, there was a clear demarcation between viable and nonviable tissue, the latter being characterized by areas of multifocal hemorrhage and pyknosis. After 4 weeks of healing, there was a well-defined line between necrotic and viable tissue.

CONCLUSION

Cryoablation of the adrenal gland can be obtained in an effective, controllable, and reproducible manner. This controllable energy form may provide new modality for tissue destruction where adrenal gland preservation is necessary and can be delivered by the laparoscopic approach. Understanding the effect of adrenal cryoablation may allow us to treat selected patients with small tumors in whom organ preservation is necessary.

Cryosurgery for Unresectable Primary Hepatocellular Carcinoma: A Case Report and Review of Literature

Primary liver cancers are a significant cause of both morbidity and mortality. Although surgical resection remains the treatment of choice for these tumors, only 10 to 20 per cent of the primary liver tumors are found to be resectable. Presently, the options for these patients include liver transplantation, cryosurgery, or nonsurgical therapy, such as transarterial chemoembolization. Techniques such as alcohol injection, interstitial radiotherapy, laser hypothermia, and radiofrequency electrodissection have all been attempted with limited success. We present a case of a 68-year-old woman with a 10-year history of liver cirrhosis secondary to chronic active hepatitis C. A lateral segmentectomy was recommended but could not be done due to severe underlying cirrhosis. Cryosurgery aided by intraoperative ultrasonography was performed successfully. The patient developed recurrent disease at 58 months and died with disease at 62 months. Advances in instrumentation and intraoperative ultrasonography are making cryosurgery a viable surgical therapeutic alternative in the management of patients with unresectable hepatocellular carcinoma. The procedure can be performed safely with low morbidity.

Indicators of recurrence following cryotherapy for hepatic metastases from colorectal cancer

BACKGROUND

This retrospective review aimed to assess the incidence of local recurrence at the cryosite, hepatic and extrahepatic recurrence and the corresponding disease-free intervals. Prognostic indicators following hepatic cryotherapy were also identified.

METHODS

Eighty-five patients underwent complete cryotreatment of colorectal liver metastases between April 1990 and May 1997. Possible prognostic indicators were tested for their impact on the disease-free interval at the cryosite, liver disease-free survival and overall disease-free survival with univariate and multivariate analysis.

RESULTS

At a median follow-up of 22 months 66 patients developed tumour recurrence: 18 in the liver only; 15 in the liver and lung; 22 in the liver and extrapulmonary areas; and 11 at extrahepatic sites only. Local recurrence at the cryosite occurred in 28 patients. Cryotreated metastases larger than 3 cm were associated with a shorter disease-free interval at the cryosite and liver disease-free survival; persistently raised serum carcinoembryonic antigen (CEA) levels after operation were associated with shorter liver disease-free and overall disease-free intervals in multivariate analysis.

CONCLUSION

Improvements in probe placement and monitoring of the freezing process are required to allow successful treatment of large liver metastases. A failure in complete postoperative CEA response indicates that hepatic or extrahepatic disease was not detected before operation, which may be avoided with better staging procedures.

Intraoperative abdominal ultrasonography

BACKGROUND

Ultrasonography during abdominal surgery has been reported since the 1960s, but its use did not become widespread until the recent availability of high-frequency, high-resolution transducers. This review discusses the application of intraoperative ultrasonography to open and laparoscopic abdominal surgery.

METHODS

A literature search (Medline) was undertaken. All papers pertaining to the subject matter that were located were included in the review.

RESULTS

Intraoperative ultrasonography influences surgical strategy in up to 50 per cent of liver resections for malignancy. It is the single most sensitive technique for the detection of occult hepatic metastases at the time of primary colorectal resection. In pancreatic surgery, intraoperative ultrasonography is of value in the localization of islet cell tumours and in the assessment of resectability of adenocarcinoma. The technique may also have a role in staging laparoscopy, and in the operative management of kidney and gastrointestinal diseases.

CONCLUSION

Ultrasonography is an ideal operative tool as it is safe, reproducible and requires no special patient preparation or positioning. It should be regarded as an essential component of major hepatobiliary and pancreatic procedures. The recent availability of flexible laparoscopic probes is likely to lead to a similar impact on minimal access surgery.

Laparoscopic cryoablation of hepatic metastases

Cryosurgery for liver metastases may improve survival for unresectable hepatic metastases. The laparoscopic approach to managing these tumors is a novel method fostered by increasing surgeon and patient interest in minimally invasive surgical techniques and the development of laparoscopic ultrasound and cryoprobes. A retrospective review of our patients who underwent laparoscopic cryoablation of hepatic tumors from April 1996 to December 1997 was conducted. We report on this experience and comment on the feasibility and safety of the procedure based on this early trial.

[Cryotherapy of liver metastases. Initial results]

PATIENTS AND METHOD

Between 1 Jan 1996 and 1 Apr 1998 29 patients underwent cryosurgical therapy for liver metastasis at the Department of Surgery at the University of Mainz.

RESULTS

No complications occurred following cryosurgery alone (n = 12). Within the group of patients with a combined procedure (n = 11) 1 patient had temporary liver failure and 1 patient died of sepsis. Following freezing of the cutting zone (n = 6) 1 patient showed a bile fistula and 1 ascites. In 15 cases of 28 dismissed patients with remaining destroyed tumor tissue the follow-up showed no tumor recurrence (median follow-up 11 months). On the other hand 9 patients had a tumor recurrence within the liver, 3 patients at extrahepatic regions and 7 patients developed a tumor recurrence within the freezing zone.

Prognostic factors after cryotherapy for hepatic metastases from colorectal cancer

OBJECTIVE

To establish the prognostic importance of different patient and tumor characteristics in cryotherapy for liver metastases from colorectal cancer.

SUMMARY BACKGROUND DATA

Hepatic cryotherapy has been used as a treatment of nonresectable liver metastases from colorectal cancer in almost 1000 patients worldwide, and its safety and efficacy are well established. However, tumor eventually recurs in most patients and they die of their disease. The knowledge of prognostic factors would allow the selection of patients who are more likely to benefit from this treatment and patients who may need additional treatment.

METHODS

Between April 1990 and May 1997, 195 patients were treated with hepatic cryotherapy. Out of this group, the authors identified 116 patients with colorectal cancer who received cryotherapy for ablation of liver metastases. Survival was estimated with the Kaplan-Meier method, using the log-rank test for univariate analysis for significance of possible prognostic factors. For multivariate analysis, a Cox regression was used.

RESULTS

One patient (0.9%) died of postoperative myocardial infarction. The total perioperative morbidity rate was 27.6%. Median survival and the 5-year survival rate were 26 months and 13.4%. The following factors were identified as independently associated with a favorable outcome: low presurgical serum level of carcinoembryonic antigen (CEA), small (< or =3 cm) diameter of cryoablated metastases, absence of untreated extrahepatic disease at laparotomy, absence of nodal involvement at primary resection, complete cryotreatment, synchronous development of liver metastases, and good or moderate differentiation of the primary tumor. Although univariate analysis suggested a favorable prognosis in patients who did not receive blood transfusion during surgery and patients younger than 51 years, this was not confirmed in multivariate analysis. In addition, normalization of the serum CEA level after treatment was an important prognostic marker in the subgroup of patients with elevated serum CEA levels before surgery.

CONCLUSIONS

Hepatic cryotherapy is a safe and effective treatment option for patients with nonresectable liver metastases from colorectal cancer, with promising results regarding survival. The prognostic factors established in this series may allow better patient selection to improve the outcome in suitable patients.

Cryoablation of human colorectal cancer in vivo in a nude mouse xenograft model

OBJECTIVE

To establish the minimum required temperature in cryoablation of human colorectal cancer cell lines grown as subcutaneous tumors in mice.

METHODS

Male nu/nu nude mice were inoculated by a sc injection of 1 x 10(6) LoVo (n = 30) or C170 (n = 32) cells. After 2 weeks the tumors were frozen using a 3-mm cryotherapy probe (LCS 3000, Cryotech, UK) to temperatures ranging from -8 to -84 degreesC.

RESULTS

(LoVo) Of 21 mice evaluable for analysis no tumors recurred in 3 mice which had their tumors frozen to less than -60 degreesC as measured at the presumed tumor/host boundary, whereas all but one tumor recurred in 18 mice which had their tumors frozen to >-60 degreesC. (C170) Of 18 mice evaluable for analysis 14 mice which had their tumors frozen to between -8 and -84 degreesC as measured at the presumed tumor/host boundary developed tumor recurrence. Four mice which had their tumors frozen to -11, -58, -62, and -81 degreesC did not develop tumor recurrence.

CONCLUSION

Cryotherapy of subcutaneous human colon cancer xenografts in nude mice results in tumor recurrence if tumors are frozen to temperatures of as low as -60 degreesC (LoVo) or -84 degreesC (C170) with a single freeze-thaw cycle. A critical temperature for the effective cryoablation of human colorectal cancer cell lines grown as subcutaneous tumors in mice with a single freeze-thaw cycle was not defined.

In vivo results with a new device for ultrasonic monitoring of pig skin cryosurgery: the echographic cryoprobe

One of the main difficulties encountered in cryosurgery is the uncertainty in the extent and depth of the tissue effectively treated during the freezing process. The objective of this study was to evaluate in vivo ultrasonic control of skin cryosurgery using a new echographic cryoprobe. An echographic cryoprobe, developed specifically for dermatology applications, combines a high-frequency (20 MHz) miniature ultrasonic transducer and a N2O-driven closed cryoprobe. Knowledge of the ultrasound velocity of frozen skin is a prerequisite for monitoring the iceball formation kinetics. Therefore, in a first study, we estimated the ultrasound velocity of frozen skin specimens. In a second step, the operation of the echographic cryoprobe was assessed, under in vivo conditions similar to those used in human therapeutics, on normal skin of three female "Large-White" pigs under anesthesia. The mean value of ultrasound velocity of frozen skin obtained by pooling the data from all the skin specimens included in this study was 2865 +/- 170 m per s. The average rates of growth (10(-2) mm per s) of the iceballs were found to be 12.2 +/- 1.0 (pig 1), 9.0 +/- 1.0 (pig 2), and 8.4 +/- 0.9 (pig 3). The echographic cryoprobe had a built-in high-frequency ultrasonic transducer that served two functions. It enabled in vivo real-time monitoring of depth penetration of the iceball and it gave important feedback to the operator or to the console relating to the rate of growth of the iceball. Automatic (i.e., operator-independent) detection of the echo signal from the freezing front and calculation of the depth penetration of the iceball was possible.

Thermal characteristics of a hepatic cryolesion formed in vitro by a 3-mm implantable cryoprobe

The objective of the investigation was to characterize the hepatic cryolesion formed with an implantable needle (3 x 100 mm) cryoprobe. This was used to produce cryolesions in isolated porcine liver tissue equilibrated to 37 degrees C in a water bath. The shape, size, and temperature zones within the cryolesion and the effect of single versus repeated freeze-thaw cycles on cryolesion size were studied. The final shape of the cryolesion at 15-20 min freezing was cylindrical and its distal hemispherical end extended 8 mm beyond the tip of the cryoprobe. The rate of increase in maximum diameter was logarithmic and decreased from 4.7 mm/min during the first 5 min to 0.4 mm/min during the fourth 5-min period of freezing. By contrast, the rate of increase in volume was linear and ranged from 9.6 to 7.9 ml/min during the corresponding periods. The volume of the hepatic cryolesion after 20 min of continuous freezing was significantly greater than that of the cryolesion formed with 20 min of cumulative freezing interrupted by a 5-min spontaneous thaw. The ultimate temperatures reached and the cooling rates varied in different zones within the cryolesion depending on distances away from and alongside the cryoprobe. Diameter measurements taken in isolation do not reflect the actual growth rate of the cryolesion. Volume measurements define more accurately the amount of tissue frozen and left in situ. Prolonged freezing beyond 20 min did not increase the diameter of the cryolesion. A single continuous freeze produces a larger cryolesion than two freeze-thaw cycles of the same freezing duration.

Treatment of colorectal liver metastases by cryotherapy

One hundred fifty-eight procedures were performed on 136 patients with unresectable hepatic metastases using hepatic cryotherapy to ablate the tumors. The median age was 62 years. Patients included 90 males and 46 females. Fifty-eight patients had synchronous metastases, 55 had bilobar lesions, and 90 had precryo chemotherapy. Median preoperative carcinoembryonic antigen (CEA) level was 14.4 ng/dl. The numbers of lesions treated, frozen, and resected were two and one. Median survival of all patients was 30 months. Survival for 39 patients was 37 months. Patients with a CEA level > 100 ng/dl had a statistically worse survival rate than those with a level < 100 ng/dl (P < .001). Twenty patients underwent recryotherapy with median survival of 34 months. Recurrent disease developed in 78% of patients--82% of the patients developed liver recurrence. Complication rates were comparable to liver resection. Operative mortality was 3.7%. Hepatic cryotherapy is effective and safe in treating colorectal hepatic metastases under ultrasound guidance.

History of cryosurgery

The use of freezing temperatures for the therapeutic destruction of tissue began in England in 1845-51 when James Arnott described the use of iced salt solutions (about-20 degrees C) to freeze advanced cancers in accessible sites, producing reduction in tumor size and amelioration of pain. Improved freezing techniques were possible early in the 1990s when solidified carbon dioxide came into use and later when liquid nitrogen and nitrous oxide became available. Nevertheless, cryotherapy was a minor technique, used only for the accessible lesions of skin and mucosa. With the development of modern cryosurgical apparatus by Cooper in 1961, a resurgence of interest in cryosurgery was initiated and techniques for diverse clinical conditions, including visceral cancer, evolved, After the initial widespread clinical trials matured in the 1970s, some applications of the technique fell into disuse while others became standard treatment. Late in the 1980s, further improvements in apparatus and imaging techniques have permitted increased clinical use in neoplastic disease, including visceral cancer.

Biochemical, hematologic, and immunologic alterations following hepatic cryotherapy

Hepatic cryosurgery causes hepatocellular damage primarily by inducing the formation of ice crystals. Cell necrosis is enhanced using two or more freeze-thaw cycles. The resultant damage to hepatocytes induces alterations in a number of biochemical and hematologic parameters, including hepatic function tests, serum bilirubin, serum and urine myoglobin, platelet count, and coagulation measures. Further, in experimental models, cryogenic surgery appears to stimulate the immune system of the host leading to an anti-tumor immune response. These perturbations in biochemical and hematologic parameters are usually transient, and long-term adverse sequelae are uncommon and preventable.

Clinical experience with cryosurgery for advanced hepatobiliary tumors

INTRODUCTION

There have been reports that suggest cryosurgical techniques may be a useful adjunct to surgical resection or even a viable alternative treatment for hepatobiliary malignancies. Our objective was to evaluate the clinical results following cryoablation in conjunction with surgical resection for advanced hepatic tumors.

MATERIALS AND METHODS

Thirty-two consecutive procedures in 31 patients with advanced liver tumors treated with cryosurgical ablation were evaluated. Cryosurgery was applied: (1) to achieve a > 1-cm tumor-free margin when standard surgical margins were close (2) with or without standard surgical resection to manage multiple tumors (3) with hepatic arterial portocath placement to increase tumor response. Cryoablation was applied to 47 of 105 lesions--independently in 4 patients and in combination with hepatic resection in 28 procedures.

RESULTS

Cryoablation was used in 11 procedures because of close surgical margins. In 21 operations cryosurgery was used for primary ablation. In 17 of these 21 patients both cryosurgery and resection were used for different lesions; in 4 cryosurgery alone was used. Transient changes in hepatic enzymes, PT, PTT, and platelets were at maximum on Postoperative Days 1-3. Surgical mortality and morbidity rates were 6 and 60%, respectively. Coagulation abnormalities were common: at least 30% reduction in platelets occurred in all patients and greater than a 50% reduction occurred in 19 of 32 (59%). Twenty patients had a PT > 15 s and 6 of these 20 also had a platelet count < 50,000. Associated complications included one wound hematoma, two GI hemorrhages, one intracranial hemorrhage, and one hepatic hemorrhage from the cryosurgical site. The actuarial patient survivals were 90, 59, 33, and 22% at 6, 12, 24, and 36 months, respectively.

CONCLUSIONS

This report helps define the risks and results of cryosurgical ablation as a complement to surgical resection for advanced hepatobiliary tumors. Management of lesions contiguous to major blood vessels may include either the Pringle maneuver or total vascular isolation. Since these procedures can have significant morbidity, we urge cautious application of cryosurgery for advanced hepatobiliary tumors in selected otherwise unresectable patients.

Multiple bilobar liver metastases: cryotherapy for residual lesions after liver resection

BACKGROUND AND OBJECTIVES

Most patients with colorectal liver metastases are not eligible for resection because they have multiple lesions or because of anatomical constraints. We report the use of cryotherapy to destroy residual metastases following liver resection in patients with disease too widespread for treatment by resection alone.

METHODS

Twenty patients with bilobar disease confined to the liver (median 3; range 2-8 lesions) were treated in this way. Seventeen patients also received regional chemotherapy postoperatively.

RESULTS

Morbidity was high, but there were no procedure-related deaths and only one patient's hospital stay exceeded 24 days. Significant destruction of tumor, as evidenced by a decline in CEA levels, occurred within 3 months of surgery in all patients (P < 0.001). Median duration of follow-up was 15 (6-53) months. Survival rates at 1 and 2 years were 88% and 60%, respectively, and median survival was 32 months. Seven patients remain well and seven are alive with recurrent liver and/or other metastases.

CONCLUSIONS

Although this is not a control study, it would appear that some patients with irresectable liver metastases benefit from this multimodality approach.

Cryosurgical ablation of hepatic tumors

BACKGROUND

Cryosurgical ablation of hepatic tumors relies on nonspecific tissue necrosis due to freezing as well as microvascular thrombosis. Patients with selected primary and metastatic hepatic malignancies who are not candidates for surgical resection are afforded potentially curative benefit using this technique.

METHODS

Forty patients underwent cryosurgery for hepatic malignancy related to colorectal metastasis (n = 27), hepatocellular carcinoma (n = 8), metastatic breast (n = 2), metastatic neuroendocrine (n = 2), and metastatic ovarian carcinoma (n = 1). Intraoperative ultrasound (IOUS) was used in all patients to help locate the tumor and guide the cryosurgical trocar to the lesions.

RESULTS

Indications for cryosurgical ablation included bilobar and centrally located disease, poor medical risk, insufficient hepatic reserve, and involved margin after wedge resection. Major complications included hepatic parenchyma cracking requiring transfusion in 5 patients, 1 postoperative biliary stenosis, and 1 inferior vena cava injury. There were 3 postoperative deaths from non-hepatic-related events. Based on Kaplan-Meier analysis the estimated overall survival for patients with hepatocellular carcinoma (60% at 18 months) was compared with patients with colorectal metastases (30% at 18 months). Nine patients (23%) are currently free of disease with an average follow-up of 17.7 months. The pattern of failure was identified at the site of cryosurgical ablation in 2 of 88 lesions.

CONCLUSIONS

Cryosurgical ablation of selected hepatic malignancies is a safe and viable treatment for patients not amenable to surgical resection.