Hepatic cryosurgery for liver metastases. Long-term follow-up

The Extent of Cryosurgery Increases the Complication Rate after Hepatic Cryoablation

Although there have been many reports on the use of cryosurgery to ablate hepatic malignancies none have specifically examined the relationship of complication rates to the extent of cryoablation. A retrospective review from January 1997 to May 2002 identified 98 patients treated with hepatic cryotherapy. The extent of the cryosurgery was determined by the total number of lesions (TNL) and total estimated area (TEA) of the lesions from preoperative evaluation by CT scan and intraoperative evaluation by ultrasound. The major complication rate was 11 per cent. The 30-day mortality was 0 per cent, but the late procedure-related mortality was 2 per cent. Increasing the extent of cryotherapy measured by intraoperative ultrasound demonstrated significant increases in the complication rate and length of stay (LOS). With cryoablation of TEA ≥30 cm2 there was a significant increase in the overall complication rate (56% vs 23%; P = 0.003) and LOS (8.8 ± 6.9 vs 6.1 ± 4.2; P = 0.022) compared with TEA <30 cm2. Performance of concurrent procedures also led to a significant increase in complications (69% vs 29%; P = 0.010) and LOS (8.6 ± 6.8 vs 6.0 ± 4.0; P = 0.019). Multivariate analysis, however, showed intraoperative TEA ≥30 cm2 to be the most significant independent predictor of increased complications and prolonged LOS.

Hepatic cryotherapy involving the vena cava. Experimental study in a pig liver model

Liver tumors located near the retrohepatic vena cava are often considered nonresectable. For these patients cryoablation could be a therapeutic option. In this study the safety and efficacy of hepatic cryosurgery involving the retrohepatic vena cava were investigated. Cryolesions involving the vena cava were created in 26 pigs. Follow-up was 24 h and 14 days. The extent of the cryolesion, damage to the vena cava and complications were assessed after autopsy. The cyronecrosis extended into the wall of the vena cava in 81% of the animals. All animals had an uneventful recovery without any complications such as ruptures of the vessel, thrombosis or pulmonary embolism. Microscopically elastic and collagenous fibers of the cava wall remained intact. The continuity of the vessel wall was conserved. In conclusion, the safety and efficacy of cryosurgical treatment involving the retrohepatic vena cava were shown in a pig model.

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.

Thermal ablation therapy for hepatocellular carcinoma

Thermal ablation strategies, including the use of radiofrequency, microwaves, lasers, and high-intensity focused ultrasound, are gaining increasing attention as an alternative to standard surgical therapies in the treatment of primary hepatocellular carcinoma. Benefits over surgical resection include the anticipated reduction in morbidity and mortality, low cost, suitability for real-time imaging guidance, ability to perform ablative procedures on an outpatient basis, and the potential application in a wider spectrum of patients-including those who are not surgical candidates. In this review, the authors examine the reported clinical success of each of these four therapies, potential complications, current limitations, and future directions of development.

Cryoablation and liver resection for noncolorectal liver metastases

BACKGROUND

Liver resection for noncolorectal liver metastases has merit for selected primary tumor types. The role of cryosurgical tumor ablation within this cohort of patients has not been evaluated. This is a single institutional review of treatment outcomes using cryosurgical ablation and conventional resection techniques for noncolorectal liver metastases.

METHODS

The medical records of 42 patients undergoing 48 hepatic tumor ablative procedures from February 1991 through May 2001 at a single institution were retrospectively reviewed. Overall survival and local hepatic tumor recurrence-free survival were analyzed for different surgical procedures and primary tumor types.

RESULTS

Overall survival rates at 1, 3, and 5 years are 82%, 55%, and 39%, respectively (median survival, 45 months). Local hepatic tumor recurrence-free survival rates for resection only (n = 25) and cryosurgery with or without resection (n = 23), at 3 years are 24% and 19%, respectively. The survival rates at 5 years are 40% and 37%, for resection only and cryosurgery with or without resection, respectively.

CONCLUSION

Cryosurgical hepatic tumor ablation for metastatic noncolorectal primary tumors results in survival and local hepatic tumor recurrence rates similar to resection alone. The combination of cryosurgery and resection extends the cohort of patients with surgically treatable disease.

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.

Disease management considerations: disease management considerations

Colorectal cancer is still a majorhealth and social problem. However, many important advances in treatment have been made in the last 4 to 5 years, and more optimism is now justified both among clinicians and patients. In surgically resectable disease, adjuvant chemotherapy has been clearly demonstrated as able to increase overall survival in patients with colon cancer Dukes' stage C, whereas the role of medical treatment in patients with Dukes' stage B colon cancer is still controversial. At present, the standard regimen is bolus fluorouracil (5-FU) modulated by folinic acid (leucovorin) for 6 months. For rectal cancer, the best adjuvant treatment seems to be represented by radiotherapy (better if administered preoperatively) combined with chemotherapy (usually based on modulated or continuously infused 5-FU). In advanced disease, many new drugs have recently emerged: the most active regimens are those combining an optimal modality of 5-FU administration (i.e. continuous infusion) and one of the most active innovative compounds (irinotecan or oxaliplatin). The role of the oral drugs (e.g. tegafur/uracil, capecitabine) is still under investigation as is the combination of agents excluding 5-FU. It is now recognised that first-line treatment must be offered to all suitable pa- tients, even though asymptomatic, and that a second-line therapy (chiefly with irinotecan) is of value in many patients with cancer that progresses during treatment with 5-FU. From a strategic point of view, the best sequence of drugs/regimens has not yet been defined, while the duration and timing of chemotherapy is still a matter for clinical research. Finally, there is an increasing interest in the role of biological prognostic factors as an aid to a patient-tailored therapy, both in the adjuvant setting and in advanced disease. To achieve further progress in knowledge in this field, we strongly recommended that more and more patients are included in clinical trials.

Hepatic cryoablation-induced multisystem injury: bioluminescent detection of NF-kappaB activation in a transgenic mouse model

Hepatic injury from cryoablation has been associated with multisystem injury, including adult respiratory distress syndrome, renal insufficiency, and coagulopathy; but the responsible mechanisms have not been well defined. In the present study we investigated the role of the transcription factor NF-kappaB in the multiorgan inflammatory response to hepatic cryoablation utilizing a novel in vivo system for determining NF-kappaB activity. Using transgenic mice expressing photinus luciferase under the control of the 5' HIV-LTR (an NF-kappaB-dependent promoter), we measured luciferase activity in the liver, lungs, and kidneys as a marker for NF-kappaB activity. Luciferase production was determined by in vivo bioluminescence and by luciferase assays of tissue homogenates. After measurement of basal luciferase activity, mice were treated with 35% hepatic cryoablation or sham laparotomy and injected with luciferin (0.75 mg/mouse). Photon emission from the liver, lungs, and kidneys was measured at multiple time points. Hepatic cryoablation induced a significant increase in photon emission by the liver, lungs, and kidneys, which correlated with markedly increased luciferase activity measured from each organ after death. Lung lavage 4 hours after cryoablation showed neutrophilic lung inflammation with increased MIP-2 levels compared with sham surgery. These findings demonstrate that 35% hepatic cryoablation is associated with NF-kappaB activation in the remnant liver and multiple distant sites, and may be causally related to the multisystem injury that is seen after direct liver injury.

Ultrasound monitoring of temperature change during radiofrequency ablation: preliminary in-vivo results

Radiofrequency (RF) ablation is an interstitial focal ablative therapy that can be used in a percutaneous fashion and permits in situ destruction of hepatic tumors. However, local tumor recurrence rates after RF ablative therapy are as high as 34% to 55%, which may be due in part to the inability to monitor accurately temperature profiles in the tissue being ablated, and to visualize the subsequent zone of necrosis (thermal lesion) formed. The goal of the work described in this paper was to investigate methods for the real-time and in vivo monitoring of the spatial distribution of heating and temperature elevation to achieve better control of the degree of tissue damage during RF ablation therapy. Temperature estimates are obtained using a cross-correlation algorithm applied to RF ultrasound (US) echo signal data acquired at discrete intervals during heating. These temperature maps were used to display the initial temperature rise and to continuously update a thermal map of the treated region. Temperature monitoring is currently performed using thermosensors on the prongs (tines) of the RF ablation probe. However, monitoring the spatial distribution of heating is necessary to control the degree of tissue damage produced.

Repeat hepatic cryotherapy for metastatic colorectal cancer

This study evaluated the risks and benefits of repeat hepatic cryotherapy for recurrent, unresectable hepatic metastases from colorectal carcinoma. Review of a prospective database identified 195 patients who underwent hepatic cryotherapy for metastatic colorectal carcinoma during a 7-year period. Of the 14 patients who underwent successful repeat cryotherapy for recurrences confined to the liver, 86% had Duke's stage D colorectal carcinoma at initial diagnosis. The median age of the 14 patients was 58 years (range 41 to 77 years). The median number of hepatic metastases was three at the first cryotherapy and two at the second cryotherapy. At a median follow-up of 71 months, the mean survival times from original diagnosis, first cryotherapy, and second cryotherapy were 53, 42, and 19 months, respectively. At the most recent follow-up, eight patients (57%) have died of their disease, four (29%) are alive with disease, and two (14%) have no evidence of disease. The mean interval between the first and second cryotherapies was 23 months. The complication rates after the first and second cryotherapies were 7% and 14%, respectively. One patient developed a wound dehiscence after the first cryotherapy. Following the second cryotherapy, one patient had a small bowel obstruction and another had a pleural effusion. There was no perioperative mortality. Repeat cryotherapy for recurrent, unresectable hepatic metastases from colorectal cancer is safe and improves survival. However, a prospective trial is needed to validate the efficacy of systemic therapy and to better define the indications for repeat hepatic cryotherapy.

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.

Rationale for the combination of cryoablation with surgical resection of hepatic tumors

Only 5% to 10% of metastatic and primary liver tumors are amenable to surgical resection. Hepatic cryoablation has increased the number of patients who are suitable for curative treatment. The aim of this study was to evaluate survival and intrahepatic recurrence in patients treated with cryoablation and resection. From June 1994 to July 1999, thirty-eight surgically unresectable patients underwent a total of 42 cryoablative procedures for 65 malignant hepatic lesions. Twenty patients underwent cryoablation alone, and 18 patients were treated with a combination of resection and cryoablation, with a minimum of 18 months' follow-up. The 38 patients had the following malignancies: primary hepatocellular carcinoma (n = 8) and metastases from colorectal cancer (n = 21), neuroendocrine tumors (n = 3), ovarian cancer (n = 3), leiomyosarcoma (n = 1), testicular cancer (n = 1), and endometrial cancer (n = 1). Patients were evaluated preoperatively with spiral CT scans and intraoperatively with ultrasound examinations for lesion location and cryoprobe guidance. Local recurrence was detected by CT. Major complications included bleeding in three patients and acute renal failure, transient liver insufficiency, and postoperative pneumonia in one patient each. Two patients (5%) died during the early postoperative interval; mean hospital stay was 7.1 days. Median follow-up was 28 months (range 18 to 51 months). Overall survival according to Kaplan-Meier analysis was 82%, 65%, and 54% at 12, 24, and 48 months, respectively. Forty-eight-month survival was not significantly different between those patients undergoing cryoablation alone (64%) and those treated with a combination of resection and cryoablation (42%). Disease-free survival at 45 months was 36% for patients undergoing cryoablation plus resection compared to 25% for those undergoing cryoablation alone. Local recurrences were detected at five cryosurgical sites, for a rate of 12% overall (5 of 42), 11% (2 of 18) for patients in the cryoablation plus resection group, and 12% (3 of 24) for those in the cryoablation alone group. For patients with colorectal metastases, survival was 70% at 30 months compared to 33% for hepatocellular cancer and 66% for other types of tumors. Patients with tumors larger than 5 cm or numbering more than three did not have significantly decreased survival. Cryoablation of hepatic tumors is a safe and effective treatment for some patients not amenable to resection. The combination of cryoablation and resection results in survival comparable to that achieved with cryoablation alone.

In vivo destruction of tumor tissue by cryoablation can induce inhibition of secondary tumor growth: an experimental study

BACKGROUND

Cryoablation has been used successfully for the local treatment of several cancers. Besides local destruction, a systemic antitumor response has been postulated after cryoablation of tumor tissue. In this study we evaluate the possible systemic antitumor response induced by cryodestruction of tumor tissue in two mouse tumor models.

METHODS

Mice received two subcutaneously placed tumor implants (thigh and flank) of the nonimmunogenic mouse colon tumor cell line, colon 26-B. After 7 days, the thigh implant was treated by cryoablation or excision and the effect on secondary tumor growth was determined by volume measurement of the nontreated flank tumor. Cytokine (IL-1alpha and TNF-alpha) levels in plasma were measured after treatment. Similar experiments were performed in nude mice using a human melanoma cell line (MV3). Moreover, in this model the effect of cryoablation on development of spontaneous lung metastases was evaluated.

RESULTS

In the colon 26-B tumor model treatment of primary tumor implants by cryoablation resulted in a significant inhibition of secondary tumor growth compared to animals treated by surgical excision (P < 0.01). Six hours after treatment, plasma levels of IL-1alpha and TNF-alpha were higher after cryoablation than after excision (P < 0.01). Also in the nude mice model cryoablation resulted in inhibition of secondary tumor growth, though not significant. Mice treated by cryoablation showed significantly less lung metastases compared to those treated by excision (P = 0.03).

CONCLUSIONS

Cryoablation of tumor tissue can result in inhibition of secondary and metastatic tumor growth. A cytokine response induced by cryoablation of tumor tissue may attribute to this feature.

CT versus sonography for monitoring radiofrequency ablation in a porcine liver

OBJECTIVE

The objective of this study was to compare CT and sonography for monitoring radiofrequency (RF) lesions in porcine livers.

SUBJECTS AND METHODS

RF lesions (n = 12) were created in three pig livers by applying 13 min of current to a multielectrode RF probe with a target temperature of 95 degrees C. Helical unenhanced CT and corresponding axial sonography were performed before ablation, at 2 min, 8 min, and immediately after ablation. Contrast-enhanced CT was performed after ablation. CT scans and sonograms were evaluated by blinded observers for conspicuity of the RF lesion, edge detection (visibility of liver-lesion interface), and artifacts. Hounsfield units were recorded at every time interval, and radiologic-pathologic correlation for lesion size and configuration was performed.

RESULTS

Mean size of RF lesions was 3. 03 +/- 0.9 cm. On CT, RF lesions had consistently lower attenuation values than surrounding liver (22.2 H lower than liver at 8 min, p < 0.0001). Echogenicity was variable with sonography (hypoechoic = 59%, hyperechoic = 25%, isoechoic = 16%). Unenhanced CT significantly improved conspicuity, edge detection of RF lesions, and decreased artifacts compared with sonography (p < 0.05). Contrast-enhanced CT improved RF lesion detection, border discrimination, and artifacts compared with sonography (p < 0.05). Unenhanced CT had the best correlation to pathologic size (r = 0.74), followed by contrast-enhanced CT (r = 0.72) and sonography (r = 0.56). Contrast-enhanced CT best correlated with lesion shape, but slightly overestimated size because of areas of ischemia peripheral to the RF lesion.

CONCLUSION

In this animal model, unenhanced CT was an effective way to monitor RF ablation compared with sonography because of increased lesion discrimination, reproducible decreased attenuation during ablation, and improved correlation to pathologic size.

Hepatic malignancies

The battle against malignancies of the liver is far from over, although tremendous strides have been made in the past decade, such as improved diagnostic capabilities, safe surgical resection, availability of safe nonsurgical ablative modalities, multimodality therapy, and aggressive approach to recurrent disease. Even after the best attempts at curative treatment, recurrence of primary and secondary malignancies of the liver continues to be the cause of demise for more than 70% of treated patients. The battle continues in the laboratories, where investigations are focused on delineating the pathophysiology of cancer on the molecular and genetic levels and mapping the patterns of cancer emergence and spread. The new millennium holds promise for formulating therapies that may improve disease-free survival for patients with malignancies of the liver.

Renal ablative cryosurgery in selected patients with peripheral renal masses

OBJECTIVES

To present the preliminary results of renal ablative cryosurgery in selected patients.

METHODS

Seven patients were treated, all of whom had small peripheral tumors and chose not to undergo partial or radical nephrectomy. Four patients underwent a rib-sparing flank incision; the remaining three underwent laparoscopy. All tumors were biopsied before cryoablation. Intraoperative ultrasound was used to monitor the cryolesion.

RESULTS

There were no intraoperative complications. The estimated blood loss averaged 111 mL. To date, 6 of the 7 patients have undergone at least one follow-up computed tomography scan (14.2 months average follow-up); all these scans demonstrated partial resolution of the lesion. Clinically, the patients tolerated the procedure without any renal complications or significant changes in creatinine.

CONCLUSIONS

This limited clinical trial has demonstrated the feasibility of treating small peripherally located renal tumors with cryosurgery with minimal morbidity and a favorable outcome. Further studies are necessary to determine the long-term efficacy of this treatment modality.

Cryotherapy extends the indications for treatment of colorectal liver metastases

BACKGROUND

Hepatic resection for colorectal metastases has been established as the best option for patients with 4 or less lesions meeting specified criteria. Recently, the use of intraoperative ultrasound has increased the detection of previously occult liver lesions, and cryotherapy has allowed the treatment of liver lesions in inaccessible areas with less destruction of normal liver in the case of multiple lesions. 14e prospectively performed hepatic resection or cryotherapy to test the hypothesis that more than 4 liver metastases could be safely and successfully treated with improved long-term survival.

METHODS

From August 1993 to January 1999, 137 patients with liver metastases from colorectal cancer were treated with hepatic resection or cryotherapy at the Medical College of Wisconsin. Preoperative and postoperative computed tomography scans, intraoperative assessments of lesion number and curability, number of blood transfusions administered, length of stay, complications experienced, and overall survival rates were reviewed.

RESULTS

One hundred thirty-seven patients were explored. Treatment consisted of resection alone in 34, cryotherapy alone in 20, both treatments in 52, and no treatment was possible in 31 patients. "Curability" was defined as complete resection or cryotherapy of all identifiable tumor at the conclusion of the operation. A Cox proportional hazards model demonstrated that survival was determined by the destruction of all identifiable metastases (P < . 001) and was not statistically influenced by age, gender type of therapy, or the number of metastases treated.

CONCLUSIONS

Surgical treatment of colorectal liver metastases remains the best option for patients with this disease. A key factor in overall survival is the destruction or resection of all identifiable disease and not the number of tumors per se. Using cryotherapy as an addition to the surgical arsenal, patients previously deemed unresectable because of the number of lesions have a chance for long-term survival. This study demonstrates improved long-term survival for "cured" patients with more than 4 metastatic lesions, thereby extending the indications for resection/ablation.

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.

Cryosurgical Effects on Growing Vessels

Cryosurgical treatment of unresectable hepatic malignancies has proven beneficial in adults. Concerns regarding its use in children include the effect on growth and the risk of injury to adjacent structures. To test the effect of cryoablation on adjacent vascular structures in a growing animal, liquid nitrogen cryoablation was performed on a juvenile murine model. Sprague Dawley rats underwent double freeze-thaw cryoablation of the abdominal aorta with interposed liver tissue. Serial sacrifices were performed over 120 days. Comparisons were made with sham-operated controls. Overall, animal growth paralleled that of sham controls through all time points. Gross examination of aortic diameter also showed similar growth in vessel size between the groups. Histologic analysis demonstrated injury after cryoablation with smooth muscle cell vacuolization, followed by cell death. Aortic media layer collapse resulted from cellular loss, however, elastin fiber composition was maintained. Aortic patency was preserved despite evidence of cellular injury and aortic wall remodeling. An associated thermal sink effect on the opposing wall was identified. After cryoablation adjacent to the abdominal aorta in adolescent rats, vascular patency is maintained and animal growth and structural function is preserved, despite cellular injury and wall compression. These observations suggest that cryoablation may be a useful treatment adjunct in young subjects.

The role and biology of cryosurgery in the treatment of bone tumors. A review

The application of liquid nitrogen as a local adjuvant to curettage in the treatment of bone tumors was introduced three decades ago. This technique, termed cryosurgery, was shown to achieve excellent local control in a variety of benign-aggressive and malignant bone tumors. However, early reports showed that cryosurgery was associated with a significant injury to the adjacent rim of bone and soft-tissue, resulting in high rates of fractures and infections. These results reflected an initial failure to appreciate the potentially destructive effects of liquid nitrogen and establish appropriate guidelines for its use. We review the biological effect of cryosurgery on bone, surgical technique, and current indications for its use.

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.

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.

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.

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.

Cryosurgical palliation of metastatic neuroendocrine tumors resistant to conventional therapy

BACKGROUND

Hepatic cryosurgery is a well-recognized modality for hepatic colon metastases. We examined its potential use for refractory neuroendocrine tumors causing progressive symptoms.

METHODS

Between July 1992 and February 1997, 19 patients (with islet cell, 7; carcinoid, 8; vasoactive intestinal peptide, 1; gastrinoma, 3) underwent cryosurgery with ultrasonography. The number of lesions frozen ranged from 1 to 16 (median, 8), and their diameters ranged from 2 to 15 cm with an average of 4 cm. Patients underwent resection of the primary tumor either before (37%) or concurrent with (32%) cryosurgery, and half underwent excision of metastases with cryosurgery. Before cryosurgery, patients received chemotherapy (63%), somatostatin (47%), interferon (10%), hepatic artery ligation (5%), radiation (10%), and/or omeprazole (16%).

RESULTS

The reduction in tumor markers reached 90% (5-hydroxyindoleacetic acid), 80% (vasoactive intestinal peptide), 90% (gastrin), 90% (pancreatic polypeptide), and 80% (serotonin). At a median follow-up of 17 months, the metastases had progressed in 11 patients (two underwent a second cryosurgical procedure that eliminated symptoms) and five had died. Subsequently an additional five patients received chemotherapy and three somatostatin. Median symptom-free and overall survival were 10 months and more than 49 months, respectively.

CONCLUSIONS

Cryosurgery dramatically relieved symptoms with significant reduction in tumor markers. The reduced tumor burden may explain the subsequent response to systemic therapy. Cryosurgery is a useful adjuvant in symptomatic patients with refractory hepatic neuroendocrine metastases.

Liver tumor ablation techniques

Despite advances in surgical technique, patients with primary and secondary liver tumors remain a difficult management problem, as most tumors are unresectable at presentation. Alternative therapies, involving the in situ destruction of liver tumors, have recently come under scrutiny as palliative options. Percutaneous ethanol injection and cryosurgery have been advocated, but both have associated technical difficulties and adverse effects. Novel liver tumor ablation techniques have recently been developed that work via the induction of localized hyperthermia. There is mounting evidence to support a hypothesis that cancer cells are more selectively sensitive to heat than are normal cells, due to the poor blood supply of neoplastic tissue and the decreased vasodilatation capacity of the neovascular bed. These ablative modalities induce a variable degree of tumor necrosis in unresectable tumors, and therefore may provide useful palliation. Clinical trials are needed to determine the true nature and degree of any palliative benefit. In addition, the determinants of treatment efficacy and the predictability of the necrotic zone must be better understood before these techniques can be contemplated as alternatives to liver resection for cure.