Outcomes of Cancer Surgery after Inhalational and Intravenous Anesthesia: a Systematic Review.

Soltanizadeh S, Degett TH and Gögenur I.

Journal of Clinical Anaesthesia 2017: 42;19-25.

Aim of Study

Study Question: Is there a difference in mortality and post operative complications in patients receiving inhalational anaesthesia (INHA) vs total intravenous anaesthesia (TIVA) during Cancer Surgery?

Design and Location

Systematic review of the literature

Inclusion Criteria:

• Population: Patients Undergoing Cancer Surgery
• Intervention: Primary Cancer Surgery with Either INHA or TIVA
• Comparison: TIVA Vs INHA
• Outcomes: Overall Mortality and Post Operative Complications
• Language –English, French, German, Spanish, Scandinavian
• Study Design/Year: No Limitations

Excluded: Animal Studies, In Vitro Studies, Anaesthetic Interventions in
combination with other simultaneous interventions

Methodology

• Systematic Search: PUBMed, SCOPUS, Embase, COCHRANE library
• Records Screened for eligibility using Cochrane approved covidence.org
• Duplications manually removed
• 2 investigators independently screened abstracts and titles
• 2 Investigators screened & discussed full text
• Conflicts evaluated in consensus with 3rd investigator
• References of included studies screened
• Studied cited also screened by SCOPUS (Cochrane approved)
• Patient Demographics collected
• Hazard Ratios / p-values / statistical analysis sought where applicable

Primary Outcome :

All cause post-operative mortality by TIVA Vs Inhalational Anaesthetic (INHA)

Secondary Outcomes

Post op morbidity: subdivided by organ system / in hospital death

Statistics

Risk of Bias Assessment tools for randomised and non-randomised studies.
(ACROBAT-NRSI and Cochrane risk of Bias Tool)

Results

5966 Studies found –> 8 Studies eligible

Primary Outcome: Mortality

• UK Study : overall increased mortality in INHA group
  Hazard Ratio = 1.47 (95% CI 1.31–1.64; p ≤ 0.001)
  but: pre-op tumour stage not reported + not adjusted for BMI
• Korean Study: prolonged recurrence-free survival in the TIVA group after
  adjusting for confounders
  Hazard Ratio 0.48 (95% CI 0.27–0.86; p = 0.014)
  But: no significant difference in overall mortality (p = 0.383) on Kaplan-Meier analysis.
• Swedish Study: No significant difference breast, colon, rectal. When 3 sites combined, an overall tendency was found with a decreased overall cancer related mortality in the TIVA group adjusting for age, sex and type of malignancy
  Hazard Ratio = 0.85 (95% CI 0.72–1.00; p-value = 0.051)
  but: Not adjusted for ASA Class, previous Hx MI
• Italy RCT: 28 pts with bladder Ca. Mortality rate for patients receiving INHA
  36%, TIVA 14%.
  But: study made no statistical analysis and follow-up time was not specified!

Secondary Outcome: Morbidity

• Postoperative complications found to be comparable in all studies.
• One retrospective study (n=156) : multivariate adjusted analysis showed
  that patients developed significantly fewer pulmonary complications
  after TIVA compared with INHA
  (odds ratio of 0.41, 95% CI 0.18–0.92, p = 0.031).

RISK OF BIAS WAS MODERATE OR SERIOUS OR UNCLEAR throughout
systematic review

Conclusions/Discussions

• One study reported a significant increase in overall mortality after INHA
  (Wigmore – UK)
• One study reported a prolonged recurrence-free survival after TIVA (Lee –
  Korea)
• One considerably biased study reported a tendency of decreased overall
  mortality after TIVA (Enlund – Sweden)
• The only randomized controlled trial reporting overall mortality had a small
  study population and an unknown follow-up time (Sofra – Italy)
• One study reported a significantly reduced risk of pulmonary complications
  after TIVA (Chang – Taiwan)

Stated Limitations from the Study

• Meta-analysis not performed
  • current evidence lack randomized clinical trials of high quality and is
    based on few published papers, include patients with heterogeneous
    cancer sites undergoing heterogeneous surgical interventions with
    different mortality risks.
• Selection bias
  • all non-randomized studies in this review, as no restricting guidelines
    were reported for the choice of anesthetic induction.
• Only all-cause mortality is reported in most studies,
  • critical aspect of the review regarding the causal anesthetic impact on
    cancer progression.
• Limited studies evaluating causalities between anesthetic methods,
  postoperative complications and mortality (either/or – not both!)

Discussion from Journal Club Meeting (?Change of Practice)

• Despite no firm evidence that TIVA definitely reduced post operative mortality,
  general feeling that it is better for cancer surgery.
• Not simply from post op recurrence perspective but in terms of the quality of the
  anaesthetic.
• Agreement that culture change needed across anaesthetic dept and ODPs to be
  more familiar with TIVA.
• The strong tendency alone is enough to persuade the majority in favour of TIVA
  over INHA for cancer surgery.
• Only argument against was in the case of high turnover lists where GA may be
  more efficient at this hospital (before staff become more used to TIVA)

Summary by Dr Z Rajput. Journal Club Meeting 29 November 2018.