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Microwave coagulation for liver metastases

  1. Malgorzata M Bala1,*,
  2. Robert P Riemsma2,
  3. Robert Wolff2,
  4. Jos Kleijnen3

Editorial Group: Cochrane Hepato-Biliary Group

Published Online: 13 OCT 2013

Assessed as up-to-date: 21 DEC 2012

DOI: 10.1002/14651858.CD010163.pub2


How to Cite

Bala MM, Riemsma RP, Wolff R, Kleijnen J. Microwave coagulation for liver metastases. Cochrane Database of Systematic Reviews 2013, Issue 10. Art. No.: CD010163. DOI: 10.1002/14651858.CD010163.pub2.

Author Information

  1. 1

    Jagiellonian University Medical College, 2nd Department of Internal Medicine, Krakow, Poland

  2. 2

    Kleijnen Systematic Reviews Ltd, York, UK

  3. 3

    School for Public Health and Primary Care (CAPHRI), Maastricht University, Maastricht, Netherlands

*Malgorzata M Bala, 2nd Department of Internal Medicine, Jagiellonian University Medical College, 8 Skawinska St, Krakow, 31-066, Poland. gosiabala@mp.pl.

Publication History

  1. Publication Status: New
  2. Published Online: 13 OCT 2013

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Characteristics of included studies [ordered by study ID]
Shibata 2000

MethodsStudy type: randomised clinical trial.

Location: Japan, single centre, hospital.

Time frame of the study: 1990 to 1997.

Inclusion criteria: histological confirmation of colorectal adenocarcinoma, multiple but fewer than 10 metastatic tumours in the liver, histological assessment by core needle biopsy of at least one of those tumours, dimension of the largest tumour less than 80 mm (measured in computed tomography with contrast), no evidence of periportal or celiac lymph node metastasis, extrahepatic distant disease, ascites (confirmed by computed tomography and ultrasonography), no sign of liver cirrhosis or chronic hepatitis.
Follow-up: 3 years.


ParticipantsTotal number of participants: 40 randomly assigned, 30 analysed (10 excluded after randomisation: 6 from intervention and 4 from control group for not fulfilling inclusion criteria).

Primary sites: resectable; colorectal cancer, Stage IB to IIIC (T2N0-T3N2).

Mean size of the tumour: mean 27 mm in intervention group and 34 in control group.

Number of tumours: range 2 to 9, mean 4.1 in intervention group, mean 3.0 in control group.

Mean age: 61 ± 10 years.

Males: 57% in intervention group, 38% in control group.


InterventionsTwo treatment groups:

  • Group 1: microwave coagulation therapy (14 participants)
  • Group 2: conventional surgery (16 participants).


Microwave coagulation therapy was performed after laparotomy with microwave tissue coagulator at an output of 60 to 100 W for 2 to 20 minutes under the guide of ultrasonography.

Conventional surgery involved lobectomy, segmentectomy, subsegmentectomy, and/or wedge resection.


OutcomesNumber of deaths at the end of follow-up; 1-, 2-, 3-year survival; disease-free interval; tumour response measures; adverse events or complications.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskEnrolled participants were assigned randomly, without stratification, according to a computer-generated, 1:1 randomization list to treatment with microwave coagulation or hepatic resection.

Allocation concealment (selection bias)Unclear riskNot mentioned.

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot mentioned.

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
High risk10 participants excluded after randomisation.

Selective reporting (reporting bias)Low riskSurvival given with P value and curve.

Other biasUnclear riskInsufficient information.

 
Summary of findings for the main comparison. Microwave coagulation vs no intervention, other ablation methods, or systemic treatments

Microwave coagulation versus no intervention, other ablation methods, or systemic treatments

Patient or population: participants with liver metastases
Settings: hospitalised
Intervention: microwave coagulation
Comparison: conventional surgery

OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No. of participants
(studies)
Quality of the evidence
(GRADE)
Comments

Assumed riskCorresponding risk

Conventional surgeryMicrowave coagulation

Time to mortality

Follow-up: 3 years
The mean time to mortality in the control groups was
25 months.
The mean time to mortality in the intervention groups was
2 months higher
(0 to 0 higher).
30
(1 study)
⊕⊝⊝⊝
very low1,2

Disease-free interval

Follow-up: 3 years
The mean disease-free interval in the control groups was
13.3 months.
The mean disease-free interval in the intervention groups was
2 months lower
(0 to 0 higher).
30
(1 study)
⊕⊝⊝⊝
very low1,2

*The basis for the assumed risk (eg, the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio.

GRADE Working Group grades of evidence:
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 1 The trial did not describe allocation concealment or blinding and excluded 25% of participants after randomisation.
2 Imprecision because the total number of events is less than 300 (a threshold rule-of-thumb value) (based on Mueller et al. Ann Intern Med 2007;146:878-881; http://www.annals.org/cgi/content/abstract/146/12/878).
 
Table 1. Adverse events or complications in patients with liver metastases treated with microwave coagulation or conventional surgery

Microwave coagulation groupConventional surgery group

Any adverse event excluding intervention-related bleeding2 (14%)3 (19%)

Intervention-related mortality00

Wound infection01 (6%)

Hepatic abscess1 (7%)0

Intestinal obstruction01 (6%)

Required blood transfusion0

 
6 (38%)

Bile duct fistula1 (7%)1 (6%)