Utility of embolization or chemoembolization as second-line treatment in patients with advanced or recurrent colorectal carcinoma

Electrocoagulation for liver metastases

BACKGROUND

Primary liver tumours and liver metastases from colorectal carcinoma are two of the most common malignant tumours to affect the liver. The liver is second only to the lymph nodes as the most common site for metastatic disease. More than half of the people with metastatic liver disease will die from metastatic complications. Electrocoagulation by diathermy is a method used to destroy tumour tissue, using a high-frequency electric current generating high temperatures, applied locally with an electrode (needle, blade, or ball). The objective of this method is to destroy the tumour completely, if possible, in a single session. With the time, electrocoagulation by diathermy has been replaced by other techniques, but the evidence is unclear.

OBJECTIVES

To assess the beneficial and harmful effects of electrocoagulation by diathermy, administered alone or with another intervention, versus no intervention, other ablation methods, or systemic treatments in people with liver metastases.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, LILACS, Science Citation Index Expanded, Conference Proceedings Citation Index - Science, CINAHL, ClinicalTrials.gov, ICTRP, and FDA to October 2020.

SELECTION CRITERIA

We considered all randomised trials that assessed beneficial and harmful effects of electrocoagulation by diathermy, administered alone or with another intervention, versus comparators, in people with liver metastases, regardless of the location of the primary tumour.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We assessed risk of bias of the included trial using predefined risk of bias domains, and presented the review results incorporating the certainty of the evidence using GRADE.

MAIN RESULTS

We included one randomised clinical trial with 306 participants (175 males; 131 females) who had undergone resection of the sigmoid colon, and who had five or more visible and palpable hepatic metastases. The diagnosis was confirmed by histological assessment (biopsy) and by carcinoembryonic antigen (CEA) level. The trial was conducted in Iraq. The age of participants ranged between 38 and 79 years. The participants were randomised to four different study groups. The liver metastases were biopsied and treated (only once) in three of the groups: 75 received electrocoagulation by diathermy alone, 76 received electrocoagulation plus allopurinol, 78 received electrocoagulation plus dimethyl sulphoxide. In the fourth intervention group, 77 participants functioning as controls received a vehicle solution of allopurinol 5 mL 4 x a day by mouth; the metastases were left untouched. The status of the liver and lungs was followed by ultrasound investigations, without the use of a contrast agent. Participants were followed for five years. The analyses are based on per-protocol data only analysing 223 participants. We judged the trial to be at high risk of bias. After excluding 'nonevaluable patients', the groups seemed comparable for baseline characteristics. Mortality due to disease spread at five-year follow-up was 98% in the electrocoagulation group (57/58 evaluable people); 87% in the electrocoagulation plus allopurinol group (46/53 evaluable people); 86% in the electrocoagulation plus dimethyl sulphoxide group (49/57 evaluable people); and 100% in the control group (55/55 evaluable people). We observed no difference in mortality between the electrocoagulation alone group versus the control group (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.94 to 1.03; 113 participants; very low-certainty evidence). We observed lower mortality in the electrocoagulation combined with allopurinol or dimethyl sulphoxide group versus the control group (RR 0.87, 95% CI 0.80 to 0.95; 165 participants; low-certainty evidence). We are very uncertain regarding post-operative deaths between the electrocoagulation alone group versus the control group (RR 1.03, 95% CI 0.07 to 16.12; 152 participants; very low-certainty evidence) and between the electrocoagulation combined with allopurinol or dimethyl sulphoxide groups versus the control group (RR 1.00, 95% CI 0.09 to 10.86; 231 participants; very low-certainty evidence). The trial authors did not report data on number of participants with other adverse events and complications, recurrence of liver metastases, time to progression of liver metastases, tumour response measures, and health-related quality of life. Data on failure to clear liver metastases were not provided for the control group. There was no information on funding or conflict of interest. We identified no ongoing trials.

AUTHORS' CONCLUSIONS

The evidence on the beneficial and harmful effects of electrocoagulation alone or in combination with allopurinol or dimethyl sulphoxide in people with liver metastases is insufficient, as it is based on one randomised clinical trial at low to very low certainty. It is very uncertain if there is a difference in all-cause mortality and post-operative mortality between electrocoagulation alone versus control. It is also uncertain if electrocoagulation in combination with allopurinol or dimethyl sulphoxide may result in a slight reduction of all-cause mortality in comparison with a vehicle solution of allopurinol (control). It is very uncertain if there is a difference in post-operative mortality between the electrocoagulation combined with allopurinol or dimethyl sulphoxide group versus control. Data on other adverse events and complications, failure to clear liver metastases or recurrence of liver metastases, time to progression of liver metastases, tumour response measures, and health-related quality of life were most lacking or insufficiently reported for analysis. Electrocoagulation by diathermy is no longer used in the described way, and this may explain the lack of further trials.

Transarterial (chemo)embolisation versus no intervention or placebo for liver metastases

BACKGROUND

The liver is affected by two of the most common groups of malignant tumours: primary liver tumours and liver metastases from colorectal carcinoma or other extrahepatic primary cancers. Liver metastases are significantly more common than primary liver cancer, and long-term survival rate after radical surgical treatment is approximately 50%. However, R0 resection (resection for cure) is not feasible in the majority of people; therefore, other treatments have to be considered. One possible option is based on the concept that the blood supply to hepatic tumours originates predominantly from the hepatic artery. Transarterial chemoembolisation (TACE) of the hepatic artery can be achieved by administering a chemotherapeutic drug followed by vascular occlusive agents, and can lead to selective necrosis of the liver tumour while it may leave normal parenchyma virtually unaffected. This can also be performed without chemotherapy, which is called bland transarterial embolisation (TAE).

OBJECTIVES

To assess the beneficial and harmful effects of TAE or TACE compared with no intervention or placebo in people with liver metastases.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, and four more databases (December 2019). We also searched two trials registers and the US Food and Drug Administration database (September 2019).

SELECTION CRITERIA

Randomised clinical trials assessing beneficial and harmful effects of TAE or TACE compared with no intervention or placebo for liver metastases.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodological procedures. We extracted information on participant characteristics, interventions, study outcomes, study design, and trial methods. Two review authors independently extracted data and assessed risk of bias. We assessed the certainty of evidence with GRADE. We resolved disagreements by discussion.

MAIN RESULTS

We included one randomised clinical trial with 61 participants (43 male and 18 female) with colorectal cancer with liver metastases: 22 received transarterial embolisation (TAE; hepatic artery embolisation), 19 received transarterial chemoembolisation (TACE; 5-fluorouracil hepatic artery infusion chemotherapy with degradable microspheres), and 20 received 'no active therapeutic intervention' as a control. Most tumours were synchronous, unresectable metastases involving up to 75% of the liver. Participants were followed for a minimum of seven months. The trial was at high risk of bias. Very-low-certainty evidence found inconclusive results for mortality at 44 months between the TAE and TACE versus no intervention groups (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.74 to 1.06; 61 participants). Local recurrence was reported in 10 participants without any details about the group allocation. Very-low-certainty evidence found little or no difference in mortality between the TAE and no intervention groups (RR 0.91, 95% CI 0.75 to 1.10; 42 participants). Median survival was 7 months from trial entry (range 2 to 44 months) in the TAE group and 7.9 months (range 1 to 26 months) in the control group, and 8.7 months after diagnosis (range 2 to 49 months) in the TAE group and 9.6 months (range 1 to 27 months) in the control group. The trial authors reported the differences were not statistically significant. There were no reported side effects in the control group. In the TAE group, 18 participants experienced short-term symptoms of 'post-embolisation syndrome', which were relieved with symptomatic treatment; one participant also had a local puncture site haematoma. Very-low-certainty evidence found little or no difference in mortality between the TACE and no intervention groups (RR 0.83, 95% CI 0.65 to 1.07; 39 participants). Median survival in the TACE group was 10.7 months (range 3 to 38 months) from trial entry, and 13.0 months (range 3 to 38 months) after diagnosis. The trial authors reported that differences between groups were not statistically significant. All participants experienced short-term nausea, with or without vomiting, immediately after treatment; one participant developed a wound infection, and one developed deep vein thrombosis. The trial did not measure failure to clear liver metastases, time to progression of liver metastases, tumour response measures, or health-related quality of life. Cancer Research Campaign, a non-profit organisation, provided a grant for the trial; Pharmacia Ltd. delivered the Port-a-Cath arterial delivery systems and degradable starch microspheres. We identified one ongoing trial comparing TACE plus chemotherapy versus chemotherapy alone in people with unresectable colorectal liver metastases who failed with first-line chemotherapy (NCT03783559).

AUTHORS' CONCLUSIONS

Based on one, small randomised trial at high risk of bias, the evidence is very uncertain about the effect of TAE or TACE versus no active therapeutic intervention on mortality for people with liver metastases as the true effect may be substantially different. The trial did not measure failure to clear liver metastases, time to progression of liver metastases, tumour response measures, or health-related quality of life. Short-term, minor adverse events were recorded in the intervention groups only. Large trials, following current standards of conduct and reporting, are required to explore the benefits and harms of TAE or TACE compared with no intervention or placebo in people with resectable and unresectable liver metastasis.

Percutaneous ethanol injection for liver metastases

BACKGROUND

The liver is affected by two of the most common groups of malignant tumours: primary liver tumours and liver metastases from colorectal carcinoma or other extrahepatic primary cancers. Liver metastases are significantly more common than primary liver cancer, and the reported long-term survival rate after radical surgical treatment is approximately 50%. However, R0 resection (resection for cure) is not feasible in the majority of patients; therefore, other treatments have to be considered. One of these is percutaneous ethanol injection (PEI), which causes dehydration and necrosis of tumour cells, accompanied by small-vessel thrombosis, leading to tumour ischaemia and destruction of the tumour.

OBJECTIVES

To assess the beneficial and harmful effects of percutaneous ethanol injection (PEI) compared with no intervention, other ablation methods, or systemic treatments in people with liver metastases.

SEARCH METHODS

We searched the following databases up to 10 September 2019: the Cochrane Hepato-Biliary Group Controlled Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE Ovid; Embase Ovid; Science Citation Index Expanded; Conference Proceedings Citation Index - Science; Latin American Caribbean Health Sciences Literature (LILACS); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We also searched clinical trials registers such as ClinicalTrials.gov, the International Clinical Trials Registry Platform (ICTRP), and the US Food and Drug Administration (FDA) (17 September 2019).

SELECTION CRITERIA

Randomised clinical trials assessing beneficial and harmful effects of percutaneous ethanol injection and its comparators (no intervention, other ablation methods, systemic treatments) for liver metastases.

DATA COLLECTION AND ANALYSIS

We followed standard methodological procedures as outlined by Cochrane. We extracted information on participant characteristics, interventions, study outcomes, study design, and trial methods. Two review authors performed data extraction and assessed risk of bias independently. We assessed the certainty of evidence by using GRADE. We resolved disagreements by discussion.

MAIN RESULTS

We identified only one randomised clinical trial comparing percutaneous intratumour ethanol injection (PEI) in addition to transcatheter arterial chemoembolisation (TACE) versus TACE alone. The trial was conducted in China and included 48 trial participants with liver metastases: 25 received PEI plus TACE, and 23 received TACE alone. The trial included 37 male and 11 female participants. Mean participant age was 49.3 years. Sites of primary tumours included colon (27 cases), stomach (12 cases), pancreas (3 cases), lung (3 cases), breast (2 cases), and ovary (1 case). Seven participants had a single tumour, 15 had two tumours, and 26 had three or more tumours in the liver. The bulk diameter of the tumour on average was 3.9 cm, ranging from 1.2 cm to 7.6 cm. Participants were followed for 10 months to 43 months. The trial reported survival data after one, two, and three years. In the PEI + TACE group, 92%, 80%, and 64% of participants survived after one year, two years, and three years; in the TACE alone group, these percentages were 78.3%, 65.2%, and 47.8%, respectively. Upon conversion of these data to mortality rates, the calculated risk ratio (RR) for mortality at last follow-up when PEI plus TACE was compared with TACE alone was 0.69 (95% confidence interval (CI) 0.36 to 1.33; very low-certainty evidence) after three years of follow-up. Local recurrence was 16% in the PEI plus TACE group and 39.1% in the TACE group, resulting in an RR of 0.41 (95% CI 0.15 to 1.15; very low-certainty evidence). Forty-five out of a total of 68 tumours (66.2%) shrunk by at least 25% in the PEI plus TACE group versus 31 out of a total of 64 tumours (48.4%) in the TACE group. Trial authors reported some adverse events but provided very few details. We did not find data on time to mortality, failure to clear liver metastases, recurrence of liver metastases, health-related quality of life, or time to progression of liver metastases. The single included trial did not provide information on funding nor on conflict of interest.

AUTHORS' CONCLUSIONS

Evidence for the effectiveness of PEI plus TACE versus TACE in people with liver metastases is of very low certainty and is based on one small randomised clinical trial at high risk of bias. Currently, it cannot be determined whether adding PEI to TACE makes a difference in comparison to using TACE alone. Evidence for benefits or harms of PEI compared with no intervention, other ablation methods, or systemic treatments is lacking.

Cryotherapy for liver metastases

BACKGROUND

The liver is affected by two of the most common groups of malignant tumours: primary liver tumours and liver metastases from colorectal carcinoma. Liver metastases are significantly more common than primary liver cancer and long-term survival rates reported for patients after radical surgical treatment is approximately 50%. However, R0 resection (resection for cure) is not feasible in the majority of patients. Cryotherapy is performed with the use of an image-guided cryoprobe which delivers liquid nitrogen or argon gas to the tumour tissue. The subsequent process of freezing is associated with formation of ice crystals, which directly damage exposed tissue, including cancer cells.

OBJECTIVES

To assess the beneficial and harmful effects of cryotherapy compared with no intervention, other ablation methods, or systemic treatments in people with liver metastases.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, and six other databases up to June 2018.

SELECTION CRITERIA

Randomised clinical trials assessing beneficial and harmful effects of cryotherapy and its comparators for liver metastases, irrespective of the location of the primary tumour.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We extracted information on participant characteristics, interventions, study outcomes, and data on the outcomes important for our review, as well as information on the design and methodology of the trials. Two review authors independently assessed risk of bias in each study. One review author performed data extraction and a second review author checked entries.

MAIN RESULTS

We found no randomised clinical trials comparing cryotherapy versus no intervention or versus systemic treatments; however, we identified one randomised clinical trial comparing cryotherapy with conventional surgery. The trial was conducted in Ukraine. The trial included 123 participants with solitary, or multiple unilobar or bilobar liver metastases; 63 participants received cryotherapy and 60 received conventional surgery. There were 36 women and 87 men. The primary sites for the metastases were colon and rectum (66.6%), stomach (7.3%), breast (6.5%), skin (4.9%), ovaries (4.1%), uterus (3.3%), kidney (3.3%), intestines (1.6%), pancreas (1.6%), and unknown (0.8%). The trial was not reported sufficiently enough to assess the risk of bias of the randomisation process, allocation concealment, or presence of blinding. It was also not possible to assess incomplete outcome data and selective outcome reporting bias. The certainty of evidence was low because of risk of bias and imprecision.The participants were followed for up to 10 years (minimum five months). The trial reported that the mortality at 10 years was 81% (51/63) in the cryotherapy group and 92% (55/60) in the conventional surgery group. The calculated by us relative risk (RR) with 95% Confidence Interval (CI) was: RR 0.88, 95% CI 0.77 to 1.02. We judged the evidence as low-certainty evidence. Regarding adverse events and complications, separately and in total, our calculation showed no evidence of a difference in recurrence of the malignancy in the liver: 86% (54/63) of the participants in the cryotherapy group and 95% (57/60) of the participants in the conventional surgery group developed a new malignancy (RR 0.90, 95% CI 0.80 to 1.01; low-certainty evidence). The frequency of reported complications was similar between the cryotherapy group and the conventional surgery group, except for postoperative pain. Both insignificant and pronounced pain were reported to be more common in the cryotherapy group while intense pain was reported to be more common in the conventional surgery group. However, the authors did not report whether there was any evidence of a difference. There were no intervention-related mortality or bile leakages.We identified no evidence for health-related quality of life, cancer mortality, or time to progression of liver metastases. The study reported tumour response in terms of the carcinoembryonic antigen level in 69% of participants, and reported results in the form of a graph for 30% of participants. The carcinoembryonic antigen level was lower in the cryotherapy group, and decreased to normal values faster in comparison with the control group (P < 0.05).

FUNDING

the trial did not provide information on funding.

AUTHORS' CONCLUSIONS

The evidence for the effectiveness of cryotherapy versus conventional surgery in people with liver metastases is of low certainty. We are uncertain about our estimate and cannot determine whether cryotherapy compared with conventional surgery is beneficial or harmful. We found no evidence for the benefits or harms of cryotherapy compared with no intervention, or versus systemic treatments.

The role of interventional oncology in the treatment of colorectal cancer liver metastases

Colorectal cancer is a leading cause of death both in Europe and worldwide. Unfortunately, 20-25% of patients with colorectal cancer already have metastases at the time of diagnosis, while 50-60% of the remainder will develop metastases later during the course of the disease. Although hepatic excision is the first-line treatment for patients with liver-limited colorectal metastases and is reported to prolong the survival of these patients, few patients are candidates. Locoregional therapy encompasses minimally invasive techniques practiced by interventional radiology. Most widely used locoregional therapies include ablative treatments (radiofrequency ablation, microwave ablation) and transcatheter intra-arterial therapies (transarterial chemoembolization, and radioembolization with yttrium-90).

The role of interventional oncology in the treatment of colorectal cancer liver metastases

Colorectal cancer is a leading cause of death both in Europe and worldwide. Unfortunately, 20-25% of patients with colorectal cancer already have metastases at the time of diagnosis, while 50-60% of the remainder will develop metastases later during the course of the disease. Although hepatic excision is the first-line treatment for patients with liver-limited colorectal metastases and is reported to prolong the survival of these patients, few patients are candidates. Locoregional therapy encompasses minimally invasive techniques practiced by interventional radiology. Most widely used locoregional therapies include ablative treatments (radiofrequency ablation, microwave ablation) and transcatheter intra-arterial therapies (transarterial chemoembolization, and radioembolization with yttrium-90).

A New Embolization Agent: Embolization of the Kidneys with Ethylene Glycol Dimethacrylate-Hydroxyethyl Methacrylate Copolymer Microbeads

Ethylene glycol dimethacrylate (EGDMA)-hydroxyethyl methacrylate (HEMA) copolymer microbeads (125-150,jm in diameter) were produced by suspension polymerization. The percent of HEMA incorporated and the swelling ratio of the non-porous microbeads produced were 12% and 22.7%, respectively. Microbeads, sterilized with ethylene oxide, were used in the embolization of the kidneys of three adult mongrel dogs by angiography. The effectiveness of the embolization was examined by angiographs after each step. In the first step of the embolization, the microbeads reached the pre-capillaries and blood flow was successfully blocked, which was confirmed by accumulation of the contrast agent within the kidneys. In angiograms after another injection, as the second step, again there were neither contrast agent movement toward the kidneys nor distribution through the paranchyme. The embolized kidneys were subjected to histopathologic examinations where pathological changes were observed.

The state of regional therapy in the management of metastatic colorectal cancer to the liver

Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality in the United States. Most colorectal cancer patients die from advanced disease, and two-thirds of CRC deaths are due to liver metastases. Liver resection provides the best curative option for patients with colorectal liver metastases (CRLM), yet only 20% of those patients are eligible for liver metastases resection for curative intent. Loco-regional treatment of CRLM may provide additional benefits in terms of down-staging for resection and prolonged hepatic disease control. This review focusses on hepatic arterial infusion, radioembolization and chemoembolization.

Transarterial chemoembolization for primary liver malignancies and colorectal liver metastasis

Management of liver malignancies, both primary and metastatic, requires a host of treatment modalities when attempting to prolong survival. Although surgical resection and transplantation continue to offer the best chance for a cure, most patients are not amenable to these therapies because of their advanced disease at presentation. Taking advantage of the unique blood supply of the liver, transarterial chemoembolization has emerged as an alternative and effective therapy for unresectable tumors. In this article, the current role along with future perspectives of transarterial chemoembolization for hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and colorectal liver metastasis are discussed.

Locoregional therapies for metastatic colorectal carcinoma to the liver--an evidence-based review

The liver is the most common visceral site of colorectal cancer metastasis and recurrence. Given that only 25% of patients with colorectal liver metastases are amenable to curative surgical resection at initial diagnosis, locoregional intra-arterial therapies including hepatic arterial infusion chemotherapy, conventional transarterial chemoembolization, drug-eluting-bead transarterial chemoembolization, and radioembolization have increasingly developed as viable treatment options. The rationale, efficacy, safety, and toxicity of each of these therapies are reviewed and stratified based on current evidence.

Interventional oncologic approaches to liver metastases

Metastatic liver disease is the most common cause of death in cancer patients. Complete surgical resection is currently considered the only curative treatment, with only about 25% of patients being amenable to surgery. Therefore, a variety of interventional oncologic techniques have been developed for treating secondary liver malignancies. The aim of these therapies is either to allow patients with unresectable tumors to become surgical candidates, provide curative treatment options in nonsurgical candidates, or improve survival in a palliative or even curative approach. Among these interventional therapies are transcatheter therapies such as portal vein embolization, hepatic artery infusion chemotherapy, transarterial chemoembolization, and radioembolization, as well as interstitial techniques, particularly radiofrequency ablation as the most commonly applied technique. The rationale, application and clinical results of each of these techniques are reviewed on the basis of the current literature. Future prospects such as gene therapy and immunotherapy are introduced.

Minimally invasive evaluation and treatment of colorectal liver metastases

Minimally invasive techniques used in the evaluation and treatment of colorectal liver metastases (CRLMs) include ultrasonography (US), computed tomography, magnetic resonance imaging, percutaneous and operative ablation therapy, standard laparoscopic techniques, robotic techniques, and experimental techniques of natural orifice endoscopic surgery. Laparoscopic techniques range from simple staging laparoscopy with or without laparoscopic intraoperative US, through intermediate techniques including simple liver resections (LRs), to advanced techniques such as major hepatectomies. Hereins, we review minimally invasive evaluation and treatment of CRLM, focusing on a comparison of open LR (OLR) and minimally invasive LR (MILR). Although there are no randomized trials comparing OLR and MILR, nonrandomized data suggest that MILR compares favorably with OLR regarding morbidity, mortality, LOS, and cost, although significant selection bias exists. The future of MILR will likely include expanding criteria for resectability of CRLM and should include both a patient registry and a formalized process for surgeon training and credentialing.

[Intra-arterial treatment of liver metastases from colorectal carcinoma]

Colorectal carcinoma is a major public health concern with its yearly mondial incidence of about one million cases and yearly mortality of 500,000 cases. The liver is the organ most frequently affected by metastases with a frequency of 40 to 60% (contemporaneous in 25% of cases). While surgical resection is the only curative therapy, many patients are not such candidates due to the infiltrative nature of the liver metastases. Systemic chemotherapy and biotherapy regimens are the conventional treatment options for patients with multiple liver metastases. Under such circumstances, intra-arterial therapy may play a major role. We will review the main types of endovascular therapies for liver metastases from colorectal carcinoma including indications, results and potential complications.

Colorectal liver metastases

The diagnosis and management of CRLM is complex and requires a multidisciplinary team approach for optimal outcomes. Over the past several decades, the 5-year survival following resection of CRLM has increased and the criteria for resection have broadened substantially. Even patients with multiple, bilateral CRLM, previously thought unresectable, may now be candidates for resection. Two-stage hepatectomy, repeat curative-intent hepatectomy, and even selected resection of extrahepatic metastases have further increased the number of patients who may be treated with curative intent. Multiple liver-directed therapies exist to treat unresectable, incurable patients with adequate survival benefit and morbidity rates.

Advances in regional chemotherapy of the liver

INTRODUCTION

Primary and secondary liver tumors resemble some of the most common causes of cancer and represent a major clinical problem owing to the poor prognosis. First-line therapeutic concepts are mainly based on surgical resection and/or systemic chemotherapy (SCT). However, many patients are not suitable for surgery or have failed SCT, although the total tumor load is still limited, which makes a regional therapy approach appealing.

AREAS COVERED

This review focuses on different types of transarterial instillation of chemotherapy, which encompasses conventional and drug-eluting transarterial chemoembolization (TACE), hepatic arterial infusion (HAI) chemotherapy and isolated hepatic perfusion (ILP).

EXPERT OPINION

TACE can be regarded as the treatment of choice in patients with multinodular hepatocellular carcinoma, but it should still be performed as a lipiodol-based regimen, while the value of doxorubicin-eluting beads needs to be exploited in further randomized controlled trials (RCTs). For patients with colorectal liver metastases, HAI chemotherapy has been challenged by the advent of more effective SCT, but encouraging results have been observed for the combination of the most recent, active drugs given by means of HAI with SCT. Nevertheless, data from RCTs comparing SCT with this transarterial regional therapy approach, as well as with TACE and ILP, are urgently needed.

A new tool to enhance the efficacy of chemoembolization to treat primary and metastatic hepatic tumors

This editorial focuses primarily on a paper that presented the clinical applications of a new material, named DC Bead embolic drug-eluting bead (DEB), which is used to modulate the blood flow in conjunction with chemotherapy in primary and metastatic hepatic tumors. DEB appears to have several advantages over alternative embolization agents, not least of which is its effective capacity of drug diffusion in tumors, thereby making it suitable for ideal treatments.

Chemoembolization of colorectal liver metastases with cisplatin, doxorubicin, mitomycin C, ethiodol, and polyvinyl alcohol

BACKGROUND

Unresectable colorectal liver metastases have a 1- and 2-year survival of 55% and 33% with current systemic therapies. The authors evaluated response and survival after transarterial chemoembolization.

METHODS

Chemoembolization with cisplatin, doxorubicin, mitomycin C, ethiodized oil, and polyvinyl alcohol particles was performed at monthly intervals for 1 to 4 sessions. Cross-sectional imaging and clinical and laboratory evaluation were performed before treatment, 1 month after treatment, and then every 3 months. A second cycle was performed for intrahepatic recurrence. Toxicity was assessed using National Cancer Institute's Common Toxicity Criteria version 3.0. Response was evaluated using Response Evaluation Criteria in Solid Tumors criteria. Progression and survival were estimated with Kaplan-Meier analysis.

RESULTS

A total of 245 treatments were performed over 141 cycles on 121 patients. Ninety-five of 141 treatment cycles were evaluable for response: 2 (2%) partial response, 39 (41%) stable disease, and 54 (57%) progression. Median time to disease progression (TTP) in the treated liver was 5 months, and median TTP anywhere was 3 months. Median survival was 33 months from diagnosis of the primary colon cancer, 27 months from development of liver metastases, and 9 months from chemoembolization. Survival was significantly better when chemoembolization was performed after first- or second-line systemic therapy (11-12 months) than after third- to fifth-line therapies (6 months) (P = .03). Presence of extrahepatic metastases did not adversely affect survival (P = .48).

CONCLUSIONS

Chemoembolization provided local disease control of hepatic metastases after 43% of treatment cycles. Median survival was 27 months overall, and 11 months when initiated for salvage after failure of second-line systemic therapy.

Regional hepatic chemotherapies in the treatment of colorectal cancer metastases to the liver

The liver is the most common site of metastatic spread of colorectal cancer (CRC). Liver may be the only site of spread in as many as 30% to 40% of patients with advanced disease and can be treated with regional therapies directed toward their liver tumors. Surgery is currently the only potentially curative treatment, with a 5-year survival rate as high as 30% to 40% in selected patients. However, fewer than 25% of cases are candidates for curative resection. A number of other locoregional therapies, such as radiofrequency or microwave ablation, cryotherapy, and chemotherapy, may be offered to patients with unresectable but isolated liver metastases. However, for most patients with metastatic spread beyond the liver, systemic chemotherapy rather than regional therapy is a more appropriate option. We review the status of various regional hepatic chemotherapies in the treatment of colorectal metastases to the liver in the light of the available, published prospective, randomized trials; this discipline has not yet been properly applied to the burgeoning use of locally ablative techniques. The regional strategies reviewed include portal venous infusion (PVI) of 5-fluorouracil (5-FU), intra-arterial chemotherapy (hepatic arterial infusion [HAI]), chemoembolization, and selective internal radiation therapy (SIRT).

Evaluation of different calibrated spherical polyvinyl alcohol microspheres in transcatheter arterial chemoembolization: VX2 tumor model in rabbit liver

PURPOSE

To assess whether porosity and compressibility of calibrated spherical polyvinyl alcohol (PVA) microspheres affect doxorubicin plasma and tumor concentrations after transcatheter arterial chemoembolization (TACE) in a VX2 rabbit model.

MATERIALS AND METHODS

Fifteen rabbits were divided into three groups of five rabbits each. Three different types of calibrated spherical PVA microspheres with variable levels of porosity and compressibility were blindly evaluated. TACE was performed by injecting a mixture of doxorubicin (5 mg) and iodized oil (0.5 mL) followed by injection of the embolic material (0.3-0.5 mL). Plasma concentrations of doxorubicin and doxorubicinol were analyzed 20, 40, 60, and 120 minutes and 2 days after TACE, and liver tissue and tumor doxorubicin concentrations were measured 2 days after TACE.

RESULTS

All calibrated spherical PVA microspheres showed similar patterns of plasma doxorubicin and doxorubicinol release and tumor concentration of doxorubicin. There were no significant differences of drug levels in either plasma or tumor in each group (P > .05).

CONCLUSIONS

After TACE in a rabbit model of liver cancer, testing of three different types of spherical PVA microspheres with varying degrees of porosity and compressibility showed no significant differences in the plasma doxorubicin release pattern and tumor doxorubicin uptake.

Colorectal liver metastases: regional chemotherapy via transarterial chemoembolization (TACE) and hepatic chemoperfusion: an update

Liver metastasis is one of the main problems encountered in colorectal cancer management as the liver is the most common metastatic site. Several treatment options are available, among which transarterial chemotherapy has proved effective in achieving some local tumour control, improving the quality of life through symptomatic control as well as survival time. The present paper is intended to provide an overview of the techniques, indications and results of regional chemotherapy, which comprises transarterial chemoembolization (TACE) and chemoperfusion. This treatment approach has symptomatic, palliative, adjuvant and potentially curative objectives. We reviewed the studies involving TACE and chemoperfusion of colorectal liver metastases during the last few years to update the previous reviews published on this subject. The results achieved were so variable, due to the variations in patient selection criteria and regimens used between the different studies. The median survival ranged from 9 to 62 months and the morphological response ranged from 14 to 76%. Technical aspects, results, and complications of this modality will be demonstrated with a detailed analysis and comments.

Combining systemic chemotherapy with chemoembolization in the treatment of unresectable hepatic metastases from colorectal cancer

Treatment of liver metastases from colorectal cancer include surgical resection, radiation, hepatic chemoembolization, immunotherapy and intravenous chemotherapy. Complete surgical resection of liver metastases is feasible only for solitary or unilobar metastasis. Unresectable hepatic metastases of colorectal origin are resistant to radiation and immunotherapy, and the unsatisfactory results of systemic chemotherapy and chemoembolization have led to more aggressive treatment. A new method that combines systemic chemotherapy and chemoembolization is proposed. In this study, data from a total of 40 patients with unresectable hepatic metastasis from colorectal cancer were collected. All of these patients received combined chemoembolization and systemic chemotherapy. Embolization was performed by the selective cannulation of right and left hepatic artery. Equal amounts of a mixture of 10 ml lipiodol, 1,500 mg 5-fluorouracil (5-FU) and 15 mg leucovorin was deployed selectively in equal parts into the main right and left hepatic artery. Two weeks following chemoembolization, patients underwent systemic chemotherapy with 2,600 mg/m2 5-FU continuous infusion for 24 h and received 150 mg leucovorin intravenous bolus. The course of chemotherapy was repeated weekly for 24 weeks. The median follow-up period was 27 months (range 10-36 months). Following the intention-to-treat principle, the objective tumor response rate was 47.5%. The median disease-free interval was 12 months and the median survival time was 16 months. Most of the patients (73%) died of hepatic failure, while the second largest group died of abdominal carcinomatosis. In conclusion, the results of this study are of sufficient interest to justify future randomized trials.

[Transarterial chemoembolization of liver metastases of colorectal carcinoma using degradable starch microspheres (Spherex): personal investigations and review of the literature]

Since two decades transarterial chemoembolization (TACE) of liver metastases has been investigated in numerous studies. However, no standardized therapeutic procedure exists so far. The present study retrospectively investigated survival, response and side effects after TACE of liver metastases in 21 patients with colorectal cancer and results are compared with previous literature. A total of 68 TACE procedures were performed. A suspension of degradable starch microspheres (DSM, Spherex) and Mitomycin C was applied selectively into hepatic arteries via a transfemoral approach. DSM effect a temporary arterial occlusion. Follow-up studies were performed by contrast enhanced spiral computed tomography (CT). The median survival was 13.8 months. Therapeutic response (according to WHO) was observed only in three patients. The progression free interval was 5.8 months. Patients developed a postembolization-syndrome (abdominal pain, fever, nausea) and increased transaminases in 27-43% of all interventions. A gastric ulcer occurred after four, cholecystitis after two TACE. As already shown in most previous studies, regardless of the used agents, also this investigation underlines the moderate therapeutic effect of TACE on colorectal liver metastases. So far, no significant survival benefit has been shown in the literature and the response rates are rather limited. In general, complications of TACE seem to be rare, but should not to be underestimated. Compared to TACE with long or permanent arterial occlusion, postembolization syndrome seems to be less pronounced using DSM. As TACE is rather a palliative therapeutic approach, DSM therefore might be more suited. Further studies on TACE of liver metastases should focus on to the patients' quality of life.

Pre-, peri-, and posttreatment imaging of liver lesions

This article provides an overview of current treatment approaches in patients with primary or secondary liver diseases. Emphasis is placed on MR imaging prior, during, and after various treatments, including liver resection, systemic chemotherapy, transcatheter arterial chemoembolization, ablative therapies, and liver transplantation. Findings described for MR imaging are directly applicable to findings for CT and potentially contrast-enhanced ultrasound. The authors' description, however, will deal mainly with MR imaging as this is the their preferred approach due to diagnostic accuracy and patient safety, and the findings are most demonstrative on MR imaging.

Chemoembolization in the Management of Liver Tumors

The dual vascular supply of the liver affords a unique opportunity to explore intraarterial therapies for hepatic malignancies. Chemoembolization is a well-established technique combining intra-arterial chemotherapy with delivery of embolic agents in order to achieve an antitumor effect due to a high local concentration and prolonged dwell time of the drug, along with select ischemia. Many tumors, such as hepatocellular carcinoma, colorectal cancer, and neuroendocrine tumors, cause symptoms and death by local growth and destruction of the liver. While there are other methods capable of controlling small or isolated hepatic neoplasms, none are suitable for the majority of these patients. Chemoembolization can produce significant results in terms of tumor shrinkage in many of these patients, and there are studies to suggest a survival advantage in hepatocellular carcinoma. Toxicity, however, may be substantial, and patient selection is crucial in order to achieve the optimal benefit of this powerful technique for individual populations.

Randomized phase II trial of embolization therapy versus chemoembolization therapy in previously treated patients with colorectal carcinoma metastatic to the liver

Locoregional therapies are useful in treating patients with colorectal cancer metastatic to the liver. A prospective randomized phase II trial of hepatic artery embolization versus hepatic artery chemoembolization was conducted to evaluate the response rates and toxicities of these therapies in the second-line setting. Patients were required to have biopsy-proven adenocarcinoma of the colon or rectum metastatic to the liver, with the liver as the sole or predominant site of metastatic disease. All patients had measurable disease and had failed at least one prior systemic chemotherapy treatment for metastatic disease. Patients were randomized to receive either embolization therapy with polyvinyl alcohol foam (Ivalon) administered as a single agent or chemoembolization using polyvinyl alcohol foam mixed with 750 mg/m2 of 5-fluorouracil and 9 million units of interferon. Drugs and embolic material were administered via the hepatic artery as a slurry with polyvinyl alcohol foam. Fifty eligible patients were enrolled. There were 24 patients in the chemoembolization arm and 26 in the embolization arm. Sixty-four percent of patients in both treatment arms had the liver as the sole metastatic site. The most common National Cancer Institute common toxicity criteria grade 3/4 toxicities were diarrhea (17%) and hepatic toxicity (8%). There was 1 (4%) treatment-related mortality due to a hepatic abscess. Four patients (15.4%) treated with embolization had a partial response (PR), and 5 patients (20.8%) treated with chemoembolization had a PR. The median survival for all patients was 11 months (95% confidence interval [CI], 8-15 months). Survival in patients with extrahepatic disease was 8 months (95% CI, 6-10 months). Survival in patients with liver-only metastases was 15 months (95% CI, 10-17 months). Embolization of the liver as second-line therapy in patients with liver-predominant metastases is safe and effective. Median survivals are comparable to other second-line therapies

Advances in the treatment of metastatic colorectal cancer

Colorectal cancer represents the third leading cause of cancer mortality in the United States. During the past four decades, 5-fluorouracil (5-FU) has served as the cornerstone of therapy for individuals with advanced colorectal cancer (ACRC). Despite numerous attempts at maximizing efficacy of 5-FU through biochemical modulation, a significant benefit in terms of survival has never been realized. The recent emergence of novel chemotherapeutic drugs employing different mechanisms of action than 5-FU has led to the incorporation of irinotecan (CPT-11) with 5-FU/leucovorin as the new standard first-line regimen for future trials. This review outlines emerging data utilizing oral fluoropyrimidines and other new agents including oxaliplatin, raltitrexed, and eniluracil. Randomized clinical trials are currently underway in an effort to define optimal combination chemotherapy regimens, scheduling of agents, duration of therapy, and choice of therapy using a variety of prognostic molecular markers.

Cost-effectiveness of hepatic arterial chemoembolization for colorectal liver metastases refractory to systemic chemotherapy

PURPOSE

To calculate the cost-effectiveness of hepatic arterial chemoembolization (HACE) for the treatment of colorectal liver metastases (CLM) over a range of survival benefits and to determine the survival benefit that HACE must confer to meet three thresholds of cost-effectiveness.

MATERIALS AND METHODS

A spreadsheet model was used to estimate the marginal direct cost of HACE compared with palliative care from a payer's perspective. Medicare reimbursement amounts represented costs, while probabilities of reembolization and complications were obtained from records of patients who underwent HACE. Marginal cost-effectiveness was calculated from marginal direct cost by varying the survival benefit of HACE compared with palliative care from 0 to 24 months. Break-even analyses were conducted to determine the survival benefit at which the cost-effectiveness of HACE would decrease below three threshold values derived from a literature review.

RESULTS

The marginal cost-effectiveness of HACE compared with palliative care, given survival benefits of 3, 6, and 12 months, was $82,385, $41,193, and $21,045 per life-year (LY) gained, respectively. Cost-effectiveness thresholds of $20,000 (strict), $50,000 (moderate), and $100,000 (generous) per LY gained required survival benefits of 12.63, 4.94, and 2.47 months, respectively, more than the expected baseline.

CONCLUSION

The cost-effectiveness of HACE for the treatment of CLM varies considerably according to the anticipated survival benefit. Results of future randomized controlled trials must demonstrate a survival benefit of nearly 5 months for HACE to meet the moderate cost-effectiveness standard of $50,000 per LY gained.

Non-surgical treatment for liver metastases

The liver is a common site for developing metastatic disease. Although any malignancy can spread to the liver, the direct passage of blood from the gastrointestinal tract to the liver via the portal circulation results in a high rate of liver metastasis from gastrointestinal tract tumours. Various radiographical tests including computed tomography and magnetic resonance imaging can detect the majority of liver metastases. Surgical resection if feasible is the treatment of choice since it produces a 5-year survival rate of about 30%. However, the majority of the patients relapse after hepatic resection, 50% relapsing in the liver. Systemic chemotherapy produces response rates of 15-30% with a median survival of 10-12 months. It is estimated that 30,000 patients each year in the USA are candidates for regional hepatic therapy. Hepatic arterial chemotherapy, hepatic artery embolization, chemoembolization, cryosurgery, ethanol injection of the tumour and radiation therapy are being investigated as potential treatment options for such patients.

Phase II trial of chemoembolization for the treatment of metastatic colorectal carcinoma to the liver and review of the literature

BACKGROUND

Hepatic artery chemoembolization represents an alternative treatment for patients whose neoplastic lesions are not amenable or have become refractory to other treatment modalities. This project was designed to test the feasibility of regional chemoembolization for patients with colorectal carcinoma metastasis to the liver who had experienced failure with one or more systemic treatments.

METHODS

Thirty patients who met the study entry criteria underwent one to three hepatic artery chemoembolizations. The chemoembolization regimen consisted of an injection of a bovine collagen material with cisplatin (10 mg/mL), doxorubicin (3 mg/mL), and mitomycin C (3 mg/mL). Repeat treatments were performed at 6- to 8-week intervals.

RESULTS

Radiologic responses, as measured by a decrease in lesion density of at least 75% of the lesion or a 25% decrease in the size of the lesion, occurred in 63% of the cases. A decrease of at least 25% of the baseline carcinoembryonic antigen level occurred in 95% of the cases. All responses were transient. Median survival for all 30 patients was 8.6 months after the initiation of chemoembolization and 29 months after the initial diagnosis of metastasis to the liver. Common toxicities included a "postembolization syndrome," which consisted of fever > 101 degrees F (83%), pain in the right upper quadrant (100%), nausea, and vomiting. Lethargy was a common occurrence (in 60+% of cases) and lasted up to 6 weeks. Hematologic toxicities included leukocytosis, anemia, and thrombocytopenia.

CONCLUSIONS

Chemoembolization is a feasible treatment modality for patients with colorectal carcinoma metastasis to the liver who have experienced failure with other systemic treatments. It results in high response rates with transient mild-to-moderate toxicity. Responses are measured in months, however, and all patients have eventual progression of disease. Patients who are able to undergo three or more chemoembolization procedures may receive the most clinical benefit.

The need for a multidisciplinary approach in the treatment of advanced colorectal cancer: a critical review from a medical oncologist and surgeon

Over the last 10 years important advances have been made in the treatment of patients with advanced colorectal cancer, particularly with surgery either alone or in combination with radiotherapy. Furthermore, despite early scepticism, several chemotherapy studies have now reported significant clinical benefits with 5-FU-based regimens and promising results have also been reported with newer agents such as raltitrexed and irinotecan. Taken together these advances now enable a significant proportion of patients to undergo treatment which will improve their quality of life, prolong survival and even result in cure in certain cases. Patients with advanced colorectal cancer can only benefit from these important advances, however, if a truly multidisciplinary approach to patient care is adopted which requires integration of the roles of the surgeon, medical oncologist and radiotherapist.

Selective chemoembolization in the management of hepatic metastases in refractory colorectal carcinoma: a phase II trial

PURPOSE

Metastatic involvement of the liver frequently determines the evolution of the clinical picture in colorectal cancer patients. We examined the efficacy and toxicity of chemoembolization in this setting, identifying prognostic factors to define patients most likely to benefit from the procedure.

METHODS

Forty patients underwent chemoembolization of metastatic liver lesions from colorectal carcinoma. Selective angiography of the hepatic artery was performed to identify the feeding vessels of the metastatic lesions. The injected chemoemulsion consisted of 1,000 mg of 5-fluorouracil, 10 mg of mitomycin C, and 10 ml of ethiodized oil in a total volume of 30 ml. Gelfoam embolization then followed, until stagnation of blood flow was achieved. Patients were evaluated for response, overall survival, and toxicities.

RESULTS

Overall median survival from date of first chemoembolization was ten months. Factors that predicted a longer median survival included favorable performance status (24 months), serum alkaline phosphatase and lactate dehydrogenase levels less than three times normal (24 and 12 months, respectively), and metastatic disease confined to the liver (14 months). Most patients tolerated the procedure well. The most common side effects were transient fevers, abdominal pain, and fatigue. Three patients died within one month from the procedure.

CONCLUSION

This study suggests that chemoembolization of hepatic metastases in colorectal cancer should be further evaluated; it may be beneficial in patients who have failed systemic chemotherapy, have a good performance status, and have metastatic disease confined to the liver.

Perfusion to colorectal cancer liver metastases is not uniform and depends on tumor location and feeding vessel

Future effective therapies for hepatic metastases may depend on a better understanding of perfusion to these tumors. The purpose of this project was to define blood flow to colorectal cancer liver metastases using quantitative autoradiography (QAR). Liver tumors were established in F1 hybrids of WF x BN rats by intrasplenic injection of a DMH-induced rat colon adenocarcinoma. Rats underwent laparotomy 4-5 weeks later and [14C]iodoantipyrine (a radiotracer) was infused via the hepatic artery (HA) or portal vein (PV). Livers were harvested, frozen in liquid nitrogen, and sectioned at 20 microns through all tumors. QAR compared optical density of cross sections of tumors to surrounding normal liver tissue. Tumor:liver perfusion ratios (T/L PR) and tumor center:tumor periphery perfusion ratios (C/P PR) were calculated. All groups were analyzed with regard to tumor location and size. Seventy-seven tumors in 6 rats in the HA infusion group were analyzed; 74 tumors in 8 rats in the PV group were analyzed. Statistical analysis was by repeated measures analysis of variance. Mean HA T/L PR = 0.97 +/- 0.13, mean PV T/L PR = 0.25 +/- 0.11. Mean HA T/L PR for deep tumors was 1.38 +/- 0.17 and for superficial tumors was 0.57 +/- 0.15 (P < 0.01). Mean HA T/L PR for small tumors was 1.09 +/- 0.12 and for large tumors was 0.86 +/- 0.21 (P = 0.27). Mean PV T/L PR for deep tumors was 0.27 +/- 0.14 and for superficial tumors was 0.24 +/- 0.15 (P = 0.71). Mean PV T/L PR for small tumors was 0.31 +/- 0.15 and for large tumors was 0.20 +/- 0.14 (P = 0.54). Mean HA C/P PR = 1.15 +/- 0.15, mean PV C/P PR = 0.81 +/- 0.14 (P = 0.06). Mean HA C/P PR for small tumors was 1.37 +/- 0.16 and for large tumors was 0.92 +/- 0.17 (P = 0.01). Mean PV C/P PR for small tumors was 0.78 +/- 0.18 and for large tumors was 0.72 +/- 0.13 (P = 0.71). HA perfusion of tumors is significantly higher than PV perfusion compared to surrounding normal liver tissue. HA perfusion varies significantly depending on tumor location. There was a trend toward HA perfusion to the tumor center being slightly greater than to the periphery whereas the reverse was seen for PV perfusion. Tumor size did not affect overall perfusion but it did affect regional HA tumor perfusion.

Regional Transcatheter Therapy of Hepatic Neoplasms

BACKGROUND: Surgical resection of hepatocellular carcinomas and metastases to the liver cannot always be performed, and systemic therapies for these entities are of limited value. The techniques of chemoembolization and hepatic artery infusion have been used for patients who are not candidates for surgery. METHODS: Chemoembolization uses percutaneous intra-arterial infusion of chemotherapeutic agents and embolic material. This provides longer contact of the agents with the tumor cells and induces ischemia. Hepatic arterial chemoinfusion uses the knowledge that hepatic cancers are supplied predominantly by the hepatic artery. RESULTS: Chemoembolization using Lipiodol, doxorubicin, and Gelfoam has promoted necrosis of unresectable hepatocellular tumors and may have prolonged patient survival. Hepatic arterial infusion with fluorinated pyrimidines produces more objective responses than systemic chemotherapy but probably does not alter survival. CONCLUSIONS: The nonsurgical treatments of chemoembolization and hepatic arterial infusion of chemotherapy have expanded our armamentarium to manage many primary and metastatic tumors in the liver. Additional approaches are needed.

Targeting of different ethiodized oil-doxorubicin mixtures to hypovascular hepatic metastases with intraarterial and intraportal injections

PURPOSE

The distribution of different ethiodized oil-doxorubicin mixtures within and around hypovascular liver metastases in athymic nude mice was compared following either intraarterial or intraportal injections.

MATERIALS AND METHODS

Six different mixtures of doxorubicin and ethiodized oil in water-soluble contrast material, shaken for 5, 10, 15, and 30 minutes, respectively, were prepared and the size of the oil droplets in the mixtures evaluated. Intraarterial and intraportal injections of mixtures shaken for 10 and 15 minutes were performed in mice bearing hypovascular hepatic colorectal metastases. In vivo video microscopy was used to evaluate microvascular flow and the biodistribution and the size of the oil droplets within and around the tumors.

RESULTS

Oil droplets smaller than 20 microns in diameter were taken up by tumor nodules. There was no significant difference in oil droplet accumulation within the tumor between intraarterial and intraportal injections. Oil droplets larger than 20 microns occluded small and medium portal branches. The optimum combination was 0.1 mL of ethiodized oil in 2 mL of diatrizoate sodium meglumine (Renografin-76) shaken for 15 minutes at 800 rpm, which formed droplets smaller than 20 microns (92%).

CONCLUSION

Avascular regions of hepatic metastases may be embolized with ethiodized oil-anticancer drug mixtures containing oil droplets smaller than 20 microns. Since these droplets penetrate to the tumor interstitium with either intraarterial or intraportal injections, chemoembolization via the arterial route seems preferable for treatment of unresectable hypovascular hepatic metastases since it is easier to perform. The conclusions drawn from this study are limited to the animal model for experimental hypovascular hepatic metastases.