title: Transarterial (chemo)embolisation versus no intervention or placebo intervention for liver metastases.
abstract: BACKGROUND
  Primary liver tumours and liver metastases from colorectal carcinoma are the two 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 patients with metastatic liver disease will die from metastatic complications. Chemoembolisation is based on the concept that the blood supply to hepatic tumours originates predominantly from the hepatic artery. Therefore, embolisation of the hepatic artery can lead to selective necrosis of the liver tumour while it may leave normal parenchyma virtually unaffected.
  
  
  OBJECTIVE
  To study the beneficial and harmful effects of transarterial (chemo)embolisation compared with no intervention or placebo intervention in patients with liver metastases.
  
  
  METHODS
  We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS, and CINAHL up to November 2011.
  
  
  METHODS
  We included all randomised clinical trials assessing beneficial and harmful effects of transarterial (chemo)embolisation compared with no intervention or placebo intervention in patients with liver metastases, no matter the location of the primary tumour.
  
  
  METHODS
  We extracted relevant information on participant characteristics, interventions, study outcome measures, and data on the outcome measures for our review as well as information on the design and methodology of the studies. Bias risk assessment of the trials, fulfilling the inclusion criteria, and data extraction from the retrieved final evaluation trials were done by one author and checked by a second author.
  
  
  RESULTS
  One randomised clinical trial fulfilled the inclusion criteria of the review. Sixty-one patients with colorectal liver metastases were randomised into three intervention groups: 22 received hepatic artery embolisation, 19 received hepatic artery infusion chemotherapy, and 20 were randomised to control, described as "no active therapeutic intervention, although symptomatic treatment was provided whenever necessary". As hepatic artery infusion chemotherapy is not in the scope of this review, we have not included the data from this intervention group. In the remaining two groups that were of interest to the review, 43 of the participants were men and 18 women. Most tumours were synchronous metastases involving up to 75% of the liver and non-resectable. The risk of bias in the trial was judged to be high.Patients were followed-up for a minimum of seven months. Mortality at last follow-up was 86% (19/22) in the hepatic artery embolisation group versus 95% (19/20) in the control group (RR 0.91; 95% CI 0.75 to 1.1), that is, no statistically significant difference was observed. Median survival after trial entry was 7.0 months (range 2 to 44) in the hepatic artery embolisation group and 7.9 months (range 1 to 26) in the control group. Nine out of 22 (41%) in the hepatic artery embolisation group and five out of 20 (25%) in the control group developed evidence of extrahepatic disease (RR 1.64; 95% CI 0.60 to 4.07). Local recurrence was reported for 10 patients in the trial without details about the trial group. Most patients in the embolisation group experienced post-embolic syndrome (82%), and one patient had local haematoma. No other adverse events were reported. The authors did not report if there were any adverse events in the control group.
  
  
  CONCLUSIONS
  On the basis of one small randomised trial that did not describe sequence generation, allocation concealment or blinding, it can be concluded that in patients with liver metastases no significant survival benefit or benefit on extrahepatic recurrence was found in the embolisation group in comparison with the palliation group. The probability for selective outcome reporting bias in the trial is high. At present, transarterial (chemo)embolisation cannot be recommended outside randomised clinical trials.
authors.affiliation: Kleijnen Systematic Reviews Ltd, York, UK. rob@systematic-reviews.com
authors.forename: Robert P
authors.initials: RP
authors.lastname: Riemsma
authors.forename: Malgorzata M
authors.initials: MM
authors.lastname: Bala
authors.forename: Robert
authors.initials: R
authors.lastname: Wolff
authors.forename: Jos
authors.initials: J
authors.lastname: Kleijnen
mesh_terms: D015179:Colorectal Neoplasms; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D006499:Hepatic Artery; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000556:secondary / Q000628:therapy*; D008297:Male; D016032:Randomized Controlled Trials as Topic