Isolated liver perfusion for non-resectable liver tumours: a review

Oxaliplatin and infliximab synergize to induce regression of colon cancer

There is currently a lack of therapeutic options for patients with advanced colon cancer. Although certain chemotherapies are able to suppress the progression slightly, the response rate is low, and side effects of treatment and tumor recurrence continue to present problems for clinicians. Tumor necrosis factor-α (TNF-α) has been identified to possess tumor-promoting properties. In the present study, the effect of anti-TNF-α treatment (infliximab) in combination with chemotherapy on colon cancer was investigated. Tumor tissue samples were collected from patients with colon cancer who received oxaliplatin (OXA) treatment. Their TNF-α expression levels were examined with regard to their sensitivity to OXA. OXA-resistant colon cancer cell lines were established to explore the effects of anti-TNF-α treatment and OXA treatment. Furthermore, an OXA-resistant colon cancer xenograft mouse model was created and the effects of the combination treatment of anti-TNF-α and OXA on the mice were assessed. The results of the present study indicated that TNF-α was increased in the tumor tissue of patients with colon cancer who were resistant to OXA and also in OXA-resistant colon cancer cell lines. Anti-TNF-α treatment using infliximab inhibited the survival of OXA-resistant colon cancer cell lines by inducing antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity effects. The combination of infliximab and OXA treatment achieved increased efficacy on the OXA-resistant colon cancer xenograft mouse model compared with treatment with OXA alone. On the basis of the results of the present study, it was concluded that infliximab may sensitize colon cancer cells to OXA treatment.

Percutaneous Isolated Hepatic Perfusion for the Treatment of Unresectable Liver Malignancies

Liver malignancies are a major burden of disease worldwide. The long-term prognosis for patients with unresectable tumors remains poor, despite advances in systemic chemotherapy, targeted agents, and minimally invasive therapies such as ablation, chemoembolization, and radioembolization. Thus, the demand for new and better treatments for malignant liver tumors remains high. Surgical isolated hepatic perfusion (IHP) has been shown to be effective in patients with various hepatic malignancies, but is complex, associated with high complication rates and not repeatable. Percutaneous isolated liver perfusion (PHP) is a novel minimally invasive, repeatable, and safer alternative to IHP. PHP is rapidly gaining interest and the number of procedures performed in Europe now exceeds 200. This review discusses the indications, technique and patient management of PHP and provides an overview of the available data.

Retrograde-outflow percutaneous isolated hepatic perfusion using cisplatin: A pilot study on pharmacokinetics and feasibility

OBJECTIVES

This study aimed to evaluate the feasibility and underlying pharmacokinetics of the retrograde-outflow technique for percutaneous isolated hepatic perfusion (PIHP).

METHODS

Retrograde-outflow PIHP was performed in 12 male pigs (weight, 37-44 kg) by redirecting hepatic outflow through the portal vein. Blood with cisplatin (2.5 mg/kg) in an extracorporeal circuit was circulated through the liver under isolation using rotary pumps with balloon catheters. Hepatic angiographic examinations were conducted during perfusion, and histopathological examinations of the organs were conducted after perfusion. The maximum platinum concentration (C max), area under the concentration-time curve (AUC), and chronologic laboratory data were measured.

RESULTS

Retrograde-outflow isolated hepatic angiography confirmed that contrast media flowed into the portal veins in all 12 pigs. The hepatic veins and inferior vena cava were not opacified. Hepatic C max (86.3 mg/l) was 39-fold greater than systemic C max (2.2 mg/l), and hepatic AUC (1330.8 min · mg/l) was 30-fold greater than systemic AUC (44.6 min · mg/l). Histopathological examinations revealed no ischaemic changes or other abnormalities in the liver, duodenum, small intestine, or colon. Within 1 week of the procedure, chronologic laboratory data (n = 3) normalized or returned to pre-therapy levels.

CONCLUSIONS

The retrograde-outflow technique appears to enable safe and feasible PIHP therapy.

KEY POINTS

• The portal vein acted as an outflow tract under retrograde-outflow PIHP. • Plasma hepatic-to-systemic exposure ratio was 39.2 for the maximum platinum concentration. • Plasma hepatic-to-systemic exposure ratio was 29.8 for the AUC. • The retrograde-outflow technique appears to enable safe and feasible PIHP.

Cavitation-enhanced MR-guided focused ultrasound ablation of rabbit tumors in vivo using phase shift nanoemulsions

Advanced tumors are often inoperable due to their size and proximity to critical vascular structures. High intensity focused ultrasound (HIFU) has been developed to non-invasively thermally ablate inoperable solid tumors. However, the clinical feasibility of HIFU ablation therapy has been limited by the long treatment times (on the order of hours) and high acoustic intensities required. Studies have shown that inertial cavitation can enhance HIFU-mediated heating by generating broadband acoustic emissions that increase tissue absorption and accelerate HIFU-induced heating. Unfortunately, initiating inertial cavitation in tumors requires high intensities and can be unpredictable. To address this need, phase-shift nanoemulsions (PSNE) have been developed. PSNE consist of lipid-coated liquid perfluorocarbon droplets that are less than 200 nm in diameter, thereby allowing passive accumulation in tumors through leaky tumor vasculature. PSNE can be vaporized into microbubbles in tumors in order to nucleate cavitation activity and enhance HIFU-mediated heating. In this study, MR-guided HIFU treatments were performed on intramuscular rabbit VX2 tumors in vivo to assess the effect of vaporized PSNE on acoustic cavitation and HIFU-mediated heating. HIFU pulses were delivered for 30 s using a 1.5 MHz, MR-compatible transducer, and cavitation emissions were recorded with a 650 kHz ring hydrophone while temperature was monitored using MR thermometry. Cavitation emissions were significantly higher (P < 0.05) after PSNE injection and this was well correlated with enhanced HIFU-mediated heating in tumors. The peak temperature rise induced by sonication was significantly higher (P < 0.05) after PSNE injection. For example, the mean per cent change in temperature achieved at 5.2 W of acoustic power was 46 ± 22% with PSNE injection. The results indicate that PSNE nucleates cavitation which correlates with enhanced HIFU-mediated heating in tumors. This suggests that PSNE could potentially be used to reduce the time and/or acoustic intensity required for HIFU-mediated heating, thereby increasing the feasibility and clinical efficacy of HIFU thermal ablation therapy.

Hemodynamics in rat liver tumor model during retrograde-outflow isolated hepatic perfusion with aspiration from the portal vein: angiography and in vivo microscopy

BACKGROUND

Orthograde percutaneous isolated hepatic perfusion (IHP) techniques using balloon occlusion catheters are relatively simple and facilitate repeated therapy, but they result in higher rates of leakage from the perfusion circuit into the systemic circulation. Therefore, a feasible protocol for percutaneous IHP with less leakage is required.

PURPOSE

To investigate hemodynamic changes in rat liver and tumor during retrograde-outflow isolated hepatic perfusion (R-IHP) with aspiration from the portal vein (PV).

MATERIAL AND METHODS

Animal experiments were approved by the Animal Experiment Ethics Committee of Lund University. Eighteen rats underwent R-IHP after laparotomy and catheterization of the PV and hepatic artery (HA). The HA, inferior vena cava (IVC), and PV were ligated, and flow through the suprahepatic IVC was controlled with a suture loop. The rats were divided into two groups to examine blood flow during R-IHP. Four rats (group 1) underwent arteriography via the HA with and without R-IHP, and 14 rats (group 2) were inoculated with tumor and examined by in vivo fluorescence microscopy of liver and tumor during R-IHP.

RESULTS

In group 1, hepatic arteriography during R-IHP confirmed arterioportal communication in all four rats, with the PV acting as an outflow tract. In vivo fluorescence microscopy in group 2 showed strong enhancement of tumors, and no blood supply from the portal venules to the tumors was seen in any of the 14 rats. Blood flow in the major portion of the hepatic lobules was stopped and the percentage of enhanced area was significantly lower in the normal hepatic lobules than in the tumors (P < 0.0001).

CONCLUSION

We confirmed reversal of blood flow concomitant with good perfusion of the liver tumor and with reduced perfusion of normal liver parenchyma during R-IHP.

Use of partial venovenous cardiopulmonary bypass in percutaneous hepatic perfusion for patients with diffuse, isolated liver metastases: a case series

OBJECTIVES

Diffuse isolated liver metastases are the dominant mode of tumor progression in a number of cancers and present a major treatment challenge for oncologists. An experimental treatment, percutaneous hepatic perfusion (PHP), utilizes partial venovenous cardiopulmonary bypass to allow administration of high-dose chemotherapy directly and solely to the liver with filtration of chemotherapeutic agents from the blood prior to its return to the systemic circulation, thereby minimizing toxic systemic effects. The following case series describes the management of 5 patients with metastatic melanoma undergoing serial PHPs.

DESIGN

A single-center experience from a national multi-center random-assignment trial comparing PHP to best alternative care (BAC) in patients with diffuse melanoma liver metastases.

SETTING

A tertiary care hospital.

PARTICIPANTS

Five patients with metastatic melanoma to the liver.

INTERVENTION

Five patients underwent a total of fifteen PHPs using a venovenous bypass circuit with hemofiltration, receiving hepatic intra-arterial melphalan, 3 mg/kg of ideal body weight, for 30 minutes with a total of 60 minutes of hemofiltration.

MEASUREMENTS AND MAIN RESULTS

Five patients tolerated the procedure well with transient hemodynamic and metabolic changes.

CONCLUSIONS

In patients with diffuse isolated liver metastases, PHP is a safe and well-tolerated procedure that can be performed more than once and is associated with marked anti-tumor activity in some patients.

SIMPLE MACHINE PERFUSION SIGNIFICANTLY ENHANCES HEPATOCYTE YIELDS OF ISCHEMIC AND FRESH RAT LIVERS

The scarcity of viable hepatocytes is a significant bottleneck in cell transplantation, drug discovery, toxicology, tissue engineering, and bioartificial assist devices, where trillions of high-functioning hepatocytes are needed annually. We took the novel approach of using machine perfusion to maximize cell recovery, specifically from uncontrolled cardiac death donors, the largest source of disqualified donor organs. In a rat model, we developed a simple 3 hour room temperature (20±2°C) machine perfusion protocol to treat non-premedicated livers exposed to 1 hour of warm (34°C) ischemia. Treated ischemic livers were compared to fresh, fresh-treated and untreated ischemic livers using viable hepatocyte yields and in vitro performance as quantitative endpoints. Perfusion treatment resulted in both a 25-fold increase in viable hepatocytes from ischemic livers, and a 40% increase from fresh livers. While cell morphology and function in suspension and plate cultures of untreated warm ischemic cells was significantly impaired, treated warm ischemic cells were indistinguishable from fresh hepatocytes. Further, a strong linear correlation between tissue ATP and cell yield enabled accurate evaluation of the extent of perfusion recovery. Maximal recovery of warm ischemic liver ATP content appears to be correlated with optimal flow through the microvasculature. These data demonstrate that the inclusion of a simple perfusion-preconditioning step can significantly increase the efficiency of functional hepatocyte yields and the number of donor livers that can be gainfully utilized.

Selective protection of human liver tissue in TNF-targeting of cancers of the liver by transient depletion of adenosine triphosphate

BACKGROUND

Tumor necrosis factor alpha (TNF) is able to kill cancer cells via receptor-mediated cell death requiring adenosine triphosphate (ATP). Clinical usage of TNF so far is largely limited by its profound hepatotoxicity. Recently, it was found in the murine system that specific protection of hepatocytes against TNF's detrimental effects can be achieved by fructose-mediated ATP depletion therein. Before employing this quite attractive selection principle in a first clinical trial, we here comprehensively investigated the interdependence between ATP depletion and TNF hepatotoxicity in both in vitro and ex vivo experiments based on usage of primary patient tissue materials.

METHODS

Primary human hepatocytes, and both non-tumorous and tumorous patient-derived primary liver tissue slices were used to elucidate fructose-induced ATP depletion and TNF-induced cytotoxicity.

RESULTS

PHH as well as tissue slices prepared from non-malignant human liver specimen undergoing a fructose-mediated ATP depletion were both demonstrated to be protected against TNF-induced cell death. In contrast, due to tumor-specific overexpression of hexokinase II, which imposes a profound bypass on hepatocytic-specific fructose catabolism, this was not the case for human tumorous liver tissues.

CONCLUSION

Normal human liver tissues can be protected transiently against TNF-induced cell death by systemic pretreatment with fructose used in non-toxic/physiologic concentrations. Selective TNF-targeting of primary and secondary tumors of the liver by transient and specific depletion of hepatocytic ATP opens up a new clinical avenue for the TNF-based treatment of liver cancers.

Isolated hepatic perfusion for the treatment of liver tumors: sunset or sunrise?

Experience with isolated hepatic perfusion (IHP) is limited to a few centers in the world because of the technical difficulties, surgery-related morbidity, and unproved efficacy in randomized trials. Experimental animal IHP models have led to exploring new ways of improving efficacy, reducing technical difficulties, and minimizing regional and systemic toxicity. Future research should be directed to the identification of suitable biologic or chemotherapeutic agents, defining clinical indications, and development of technical modifications to make it more generally applicable and even repeatable.

Correlation between melphalan pharmacokinetics and hepatic toxicity following hyperthermic isolated liver perfusion for unresectable metastatic disease

BACKGROUND

In the present work, we report on the results of our pilot study of hyperthermic isolated hepatic perfusion (IHP) with melphalan alone for patients with unresectable metastatic liver tumors refractory to conventional treatments, with particular regard to the correlation between pharmacokinetic findings and hepatic toxicity.

PATIENTS AND METHODS

Inclusion criteria were unresectable liver metastases, hepatic parenchyma replacement <or=50%, normal liver function, and previous failure of at least one conventional treatment. IHP was performed under hyperthermic conditions with melphalan (1.5 mg/kg body weight). Completeness of vascular isolation of the liver and drug distribution volumes of the perfusion circuit were assessed by a radiolabeled albumin-based method. Drug concentrations in perfusate and plasma were measured by means of high-performance liquid chromatography (HPLC).

RESULTS

Twenty patients with unresectable liver metastases underwent IHP. No intraoperative mortality occurred. Treatment-related systemic toxicity was minimal and reversible. Three patients (15%) experienced grade 4 hepatic toxicity and died due to liver failure and subsequent multiorgan failure. Other six patients had significant (grade 3-4) but transitory hepatic toxicity. Complete and partial responses were observed in three and nine out of 17 evaluable patients, respectively (overall response rate = 70%). The pharmacokinetics study showed a 3% mean perfusate-to-plasma drug leakage (range 1-6%). Logistic regression analysis showed that drug concentration in the perfusate circuit, but not preoperative tests, significantly and independently correlated with hepatic toxicity (P = 0.028).

CONCLUSIONS

Following melphalan-based IHP, objective tumor regression could be observed in a remarkable percentage of patients refractory to standard treatments. However, hepatic toxicity and related mortality were significant. Our findings suggest that drug dosage personalization based on the measurement of drug distribution volumes might minimize hepatic toxicity.

Intravenous and isolated limb perfusion delivery of wild type and a tumor-selective replicating mutant vaccinia virus in nonhuman primates

In this study we examine the safety, feasibility, and biodistribution of a tumor-selective mutant vaccinia (vvDD) and wild-type WR (vF13) vaccinia after delivery via intradermal or intravenous infection or isolated limb perfusion (ILP) in rhesus macaques. By intradermal inoculation, 10(6) PFU of vvDD caused a minimal skin reaction whereas vF13 caused marked erythema and necrosis with a peak indurated area of 108 cm2. By intravenous delivery, vvDD caused no clinical symptoms of viremia and no viral recovery from tissues, serum, saliva, urine, or feces. In contrast, vF13 caused symptoms of lethargy, anorexia, fever, and signs of viremia. Delivery of vF13 via ILP resulted in numerous cutaneous pox lesions localized solely to the perfused limb with high viral recovery in the perfused skin and muscle. ILP with vvDD resulted in no visible pox lesions and no clinical signs or symptoms of viremia. No long-term toxicity was identified after ILP with 10(9) PFU of vvDD, and no virus was recovered from any tissue, serum, saliva, urine, or fecal sample. These results suggest that vvDD appears to be safe in primates, and thus vvDD should be further investigated for clinical trial in human cancer patients.

Laparoscopic hepatic artery catheterization for regional chemotherapy

BACKGROUND

Metastatic disease isolated to the liver is present at the time of diagnosis in 20-30% of patients with colorectal cancer. Only 10% of patients are eligible for resection. Systemic chemotherapy remains the primary treatment modality for such patients. The morbidity associated with regional chemotherapy is largely a result of the laparotomy required to place a hepatic arterial infusion pump in these debilitated patients. We discuss the main advantages of laparoscopic approach in comparison to both open procedure and percutaneous hepatic artery catheterization.

MATERIAL AND METHODS

From November 1993 to April 2004, 27 patients (16 males, 11 females) underwent laparoscopic placement of a hepatic artery catheter. The mean age was 64.9 years (46 to 82 years). 24 patients (88.8%) had bilobar disease precluding surgical resection of the liver metastases. There were four cases of non-colon cancers, all with liver metastases.

RESULTS

LHAC alone averaged 45-55 minutes. Mean blood loss of 151 cc (20-300 cc). Postoperatively, 16 patients (59.2%) had hepatic intra-arterial chemotherapy in the recovery room as a preplanned protocol. Average hospital stay was 8.4 days (3-25 days). Median follow-up period of 8.1 months. 22 patients with residual hepatic disease, in whom chemotherapy was successfully instituted, showed regression of their metastases, in 18 patients, CEA had improved at their one-month follow-up visit. Three complications: one catheter thrombosis, one partial catheter occlusion and one eroded catheter into the duodenum one year after.

CONCLUSIONS

In experienced hands, laparoscopic hepatic artery catheterization is a safe, feasible and minimally invasive technique for those patients with metachronous liver malignancies.

Bio-chemotherapeutic strategies and the (dis) utility of hypoxic perfusion of liver, abdomen and pelvis using balloon catheter techniques

AIMS

To review the development and current status of balloon catheter mediated hypoxic perfusion of abdomen, pelvis and liver for treatment of locally advanced malignancies. Within this context we focus on the addition of tumour necrosis factor-alpha (TNF) to these minimal invasive perfusion procedures.

METHODS

A literature search on these topics was carried out in PubMed for indexed articles and in all issues of Regional Cancer Treatment. The findings were related to our own experiences.

RESULTS

Hypoxic abdominal (HAP) and hypoxic pelvic perfusion (HPP) using balloon catheters, are currently applied modalities for treatment of a wide variety of abdominal and pelvic tumours, yet scientific validation of these procedures is poor. Following the results of several Phase I-II trials, both treatments are associated with severe systemic toxicity, significant morbidity and even mortality. The degree of systemic leakage associated with these procedures prohibits addition of TNF. For leakage free liver perfusion surgery is still required, as with current balloon catheter techniques it is not possible to perform leakage free isolated hypoxic hepatic perfusion (IHHP), using either orthograde or retrograde hepatic flow. Experimental and clinical observations suggest that within any perfusion setting, the utilization of TNF is only indicated for treatment of highly vascularised tumours and not for treatment of colorectal tumours.

CONCLUSION

Balloon catheter technology in its present form does not provide adequate leakage control in any of these settings and is therefore associated with considerable toxicity. It is associated with poor response rates and cannot be considered in any setting as a standard of care.

Balloon catheter hypoxic pelvic perfusion with mitomycin C and melphalan for locally advanced tumours in the pelvic region: A phase I—II trial

AIMS

To investigate the feasibility of hypoxic pelvic perfusion (HPP), using balloon catheter techniques as treatment modality for locally advanced pelvic malignancies.

METHODS

In a phase I--II study, 16 patients with various non-resectable pelvic tumours were treated with two HPP with MMC and melphalan, followed by radiotherapy (25 Gy) and surgical resection if feasible. Toxicity and procedure related complications were documented. Tumour responses were assessed by MRI or CT. Pain reductive effects were assessed by evaluation of pain registration forms.

RESULTS

HPP resulted in augmented regional drug concentrations with relatively low systemic levels. Some severe systemic toxicity was observed. One procedure related death occurred. Pain reduction effects were short-lived. Ten patients had radiological NC, two PD and one PR. In 11 patients surgical resection was performed, which was microscopically radical in six cases. Mean survival was 26.8 months (range 1--86).

CONCLUSION

The seemingly favorable pharmacokinetic profiles observed with HPP in this and other studies can still lead to severe systemic toxicity. In terms of survival, local (re-)recurrence and pain reduction there seems no benefit of addition of HPP to pre-operative radiotherapy. HPP with MMC and melphalan, does not seem a therapeutic option in patients with locally advanced pelvic tumours.

Validation of bioluminescence imaging of colorectal liver metastases in the mouse

BACKGROUND

In mouse models for metastatic growth of colorectal carcinoma (CRC) cells in the liver, tumor growth is routinely measured by determining the area of liver tissue that has been replaced by tumor tissue (hepatic replacement area [HRA]). This technique has several major disadvantages. Modern visualization techniques make it possible to image tumor growth noninvasively. In the present report, we validated bioluminescence imaging of liver metastases by comparing it to standard HRA measurements and liver weight.

MATERIALS AND METHODS

BALB/c mice received an intrasplenic injection of luciferase-expressing C26 CRC cells and the spleen was subsequently removed. On days 5, 7, 9, and 11 after injection, luciferase activity was measured. After imaging, the mice were sacrificed and the livers was removed, weighed, and fixed. HRA was determined by analyzing liver tissue sections. Comparative trend analyses between luciferase activity, wet liver weight, and HRA were then performed.

RESULTS

Luciferase activity, wet liver weight, and HRA all increased over time. Statistical analyses showed that all three types of measurements display a highly significant degree of correlation.

CONCLUSIONS

The measurement of tumor growth in the liver by imaging luciferase activity correlates well with the standard method of determining the HRA and with the increase in liver weight that results from tumor growth. Given the great advantages of measuring luciferase activity over measuring HRA, we conclude that bioluminescent imaging is a reliable and superior method for measuring experimental CRC growth in the liver.

Balloon catheter hypoxic abdominal perfusion with Mitomycin C and Melphalan for locally advanced pancreatic cancer: a phase I-II trial

BACKGROUND

Developments in balloon catheter methodology have made hypoxic abdominal perfusion (HAP) with anti-tumour agents possible with only minimal invasive surgery. The initial reports on this modality and celiac axis stop-flow infusion for treatment of pancreatic cancer were very promising in terms of tumour response, median survival and pain reduction. Recent reports, however, have not been able to confirm these results and some have disputed the efficacy of these currently still applied treatment modalities.

METHODS

Twenty-one patients with advanced pancreatic carcinoma were included in a phase I-II trial of HAP with MMC and Melphalan followed by celiac axis infusion (CAI) with the same agents six weeks later. Tumour response was assessed by abdominal-CT and by determining tumour markers. Effect on pain reduction was assessed by evaluation of pain registration forms.

RESULTS

HAP resulted in augmented regional drug concentrations. One patient died after CAI due to acute mesenterial ischaemia. One agent-toxicity related death was observed in the phase-I study. Significant hematological toxicity was observed after HAP and CAI at MTD. No patients were considered resectable after treatment. Median survival after HAP was 6 months (range 1-29). Pain reduction was experienced by only 5/18 patients and was short-lived.

CONCLUSION

In contrast to earlier reports HAP and CAI with MMC and Melphalan did not demonstrate any benefit in terms of tumour response, median survival and pain reduction, compared to less invasive treatment options. As this treatment was associated with significant toxic side-effects and even one procedure related death, we do not consider this a therapeutic option in patients with advanced pancreatic cancer.

Chemoinducible gene therapy: A strategy to enhance doxorubicin antitumor activity

A replication-defective adenoviral vector, Ad.Egr-TNF.11D, was engineered by ligating the CArG (CC(A/T)6GG) elements of the Egr-1 gene promoter upstream to a cDNA encoding human tumor necrosis factor-α. We report here that Ad.Egr-TNF.11D is activated by the clinically important anticancer agents cisplatin, cyclophosphamide, doxorubicin, 5-fluorouracil, gemcitabine, and paclitaxel. N-acetylcysteine, a free radical scavenger, blocked induction of tumor necrosis factor-α by anticancer agents, supporting a role for reactive oxygen intermediates in activation of the CArG sequences. Importantly, resistance of PC-3 human prostate carcinoma and PROb rat colon carcinoma tumors to doxorubicin in vivo was reversed by combining doxorubicin with Ad.Egr-TNF and resulted in significant antitumor effects. Treatment with Ad.Egr-TNF.11D has been associated with inhibition of tumor angiogenesis. In this context, a significant decrease in tumor microvessel density was observed following combined treatment with doxorubicin and Ad.Egr-TNF.11D as compared with either agent alone. These data show that Ad.Egr-TNF.11D is activated by diverse anticancer drugs.

True versus mild hyperthermia during isolated hepatic perfusion: effects on melphalan pharmacokinetics and liver function

Hyperthermic antiblastic isolated hepatic perfusion (IHP) with melphalan has been recently proposed as an alternative therapeutic option for patients with unresectable liver tumors. Although melphalan-heat antiblastic synergism is at a maximum at temperatures higher than 41 degrees C, IHP has so far been performed in humans at lower temperatures. In this experimental work, we compared IHP under mild versus true hyperthermic conditions in terms of drug pharmacokinetics and liver function. Ten pigs were submitted to IHP with melphalan 1.5 mg/kg at a mean temperature of 40 degrees C (group A, n = 5) or 42 degrees C (group B, n = 5). After a 60-minute perfusion, a 15-minute washout was performed. Perfusate-to-plasma leakage was monitored using scintigraphy. Throughout perfusion, samples from the systemic blood, perfusate, and liver parenchyma were obtained to measure melphalan concentrations. Liver function was assessed using standard blood tests and the indocyanine green-based test. No deaths related to the IHP procedure were recorded. All animals had transient liver function impairment, with all liver function test results returning to normal within the observation period. At histologic examination, liver damage was similar under both hyperthermic conditions. Melphalan levels in the perfusate were not significantly different in the two study groups (the mean perfusate/plasma area under the curve from 0 to 60 minutes ratios were 463 and 501, respectively). These results correlated well with those obtained using the scintigraphic method. Liver drug concentrations remained unchanged after true hyperthermia IHP. Under true hyperthermic conditions, neither an increase in liver parenchyma toxicity nor changes in melphalan pharmacokinetics were observed. These findings support the use of true hyperthermia in the clinical setting to exploit fully the antitumor synergism between melphalan and heat.

Isolated hepatic perfusion: experimental evidence and clinical utility

Many patients with tumors confined to the liver are not amenable for surgical resection, and an increasing number of these patients are treated by local ablation methods. Isolated hepatic perfusion is another treatment option especially suitable for patients with multiple or bulky primary or metastatic tumors. and can mediate clinical regression of advanced liver metastases. Experience with IHP is still limited to a few centers in the world because of its technical difficulties, surgery-related morbidity, and unproven efficacy. IHP remains an experimental modality restricted to specialized units dedicated to treating this difficult group of patients. Experimental animal IHP models have led us to explore new ways of improving efficacy, reducing technical difficulties, and minimizing regional and systemic toxicity. Future research should be directed to the identification of suitable biological or chemotherapeutic agents, defining clinical indications, and development of technical modifications to make it more generally applicable.