Take Home Message
This paper is unlikely to convince our HPB anaesthetists to switch to TIVA from desflurane once our new BIS enabled anaesthetic machines are in use.
Background
- Animal models and human cell lines suggest anaesthetic agents can affect the immune system in different ways
- Previous studies have suggested propofol based anaesthesia may be associated with a lower risk of cancer recurrence although results in liver surgery have been conflicting
Aim
Does the choice of desflurane vs propofol anaesthesia was associated with long-term survival, local recurrence, and distant metastasis after hepatectomy for HCC.
Design
- Retrospective, propensity score matched
- Single centre in Taipei, Taiwan
- January 2005 – December 2014
Eligibility criteria
- ASA 2-3
- TNM stage I-IV HCC
- Propofol or desflurane maintenance anaesthesia
- Exclusion criteria: Combined propofol with inhalational anaesthesia, incomplete data, age <20yrs, undergoing liver transplant
Methodology
- Retrospective database review
- Data collected on demographics, functional status, anaesthetic method, surgical complications, recurrence, metastasis and survival
- Induction: No pre-med, routine monitoring including arterial and central venous pressures, Fentanyl, propofol & rocuronium / cisatracurium
- Prop group: TCI aiming Ce 3-4 mg mL-1, PRN Fent / CisTrac, 100% O2 at 0.3 L min-1
- Des Group: Vapouriser at 4-10 vol% in 100% O2 at 300 mL min-1, PRN Fent / CisTrac
- Post-op: PACU / ICU
- Study size: Power calculation based on Wigmore et al, estimating 213 patients per group based on a propofol mortality 13.5% & des mortality 24%
- Statistical analysis: Students t-test / χ2, Cox proportional hazards to guide propensity scoring, Kaplan-Meier
Outcomes
- Primary: Overall survival (date of surgery to date of death or Aug 2017 for those censored)
- Subgroups: TNM stage, local recurrence & distal metastasis
Results
- Multiple statistical differences between groups, reduced but not excluded following propensity matching (blood transfusion, retroviral therapy)
- Primary outcome: Mortality higher in the desflurane group (75.0%) than in the propofol group (30.8%) during follow-up (P<0.001) confirmed following regression analysis and propensity matching (HR 0.32; 95% CI, 0.26–0.39; P<0.001)
- Subgroups: Patients who received propofol anaesthesia had less local recurrences and distant metastases than those who received desflurane anaesthesia: crude HR was 0.32 (95% CI, 0.27–0.38; P<0.001), PS-adjusted HR was 0.43 (95% CI, 0.36–0.52; P<0.001), and PS-matched HR was 0.44 (95% CI, 0.36–0.54; P<0.001)
Study Limitations
- Retrospective
- Non-random
- There may be unmeasured confounders
- No NSAID use although their use may be protective
- Opiate data not available, known to have an immune effect
Discussion
- Difficult to interpret the results given the large differences in baseline variables
- Propensity scoring and matching can help reduce the limitations of retrospective analysis but can’t exclude them completely
- Probably doesn’t apply to our population given the prevalence of Hep B/C compared to our local population (ETOH)
- Several similar studies suggest similar, although prospective studies have not confirmed the results (breast surgery in particular)
- Paper likely to be used as evidence by local pro-TIVA cancer centres to justify their technique
- Equally paper can also be used by other pro-inhalational centres (including ours – desflurane preferred) given the limitations & confounders
- There may be environmental concerns that increase the use of TIVA irrespective of oncogenic differences
Summary by Dr Timothy A C Snow