Can the type of anaesthetic you get when you have your cancer surgery effect how long you live afterwards? Well the answer is.................. maybe.

Listen to my 6min discussion here:

https://www.obsgynaecritcare.org/wp-content/uploads/2017/09/Doestheanaestheticeffectcanceroutcomes.m4a

I wouldn't be surprised that if you aren't an anaesthetist you may have never heard this topic discussed before. For those of us working in the anaesthesia field though this is a topic which has quietly been building momentum over the last decade or more and has really been getting a lot more press in the leading anaesthesia journals in the last couple of years.

I was unable to attend the recent ANZCA ASM held in Brisbane but luckily they now provide us access to listen to recordings of many of the presentations online and one of the sessions on "onco-anaesthesia" caught my eye. I especially impressed with one speaker who discussed the following recently published paper. They analysed the outcomes of a large number of patients, who underwent cancer surgery at the Marsden Hospital (a large cancer centre in the UK) & compared propofol to volatile anaesthetics. This was observational and retrospective so not the evidence you need to claim cause and effect but even after adjusting fo

r known confounding with regression there was an obvious increased mortality in patients who had the volatile anaesthetic - definitely food for thought:

Check out the article below:

Wigmore TJ1, Mohammed K, Jhanji S.Long-term Survival for Patients Undergoing Volatile versus IV Anesthesia for Cancer Surgery: A Retrospective Analysis. Anesthesiology. 2016 Jan;124(1):69-79

What's the scientific basis and explanation for this possible effect?

The science and the debate is actually quite complex and encompasses a number of related but different questions:

When having  a GA is total intravenous anaesthesia (usually an infusion of propofol +/- remifentanil)  better than a volatile or inhaled anaesthetic (eg sevoflurane / isoflurane)?

Does the use of a regional technique (spinal / epidural / local anaesthetic block) lead to a better outcome than a GA (general anaesthetic)?

Is the use of opioids detrimental too?

At present we can only say that the answer to all 3 of those questions is - well maybe.......

In the interests of time / space lets briefly delve into the explanation for claim number 1 - volatile versus intravenous anaesthesia.

Why is what happens at the time of cancer resection so important?

Surgical resection is currently still the common primary treatment of many cancers - and this is especially in true gynaecological malignancies such as endometrial, ovarian, vulval and cervical cancer.

At the time of surgical resection it is recognised that malignant cells can be "dislodged" into the circulation. Surgery & anaesthesia are associated with alterations to the neuroendocrine and immune systems which could impair the immune response and decrease the ability to prevent metastasis / implantation / angiogenesis and proliferation of malignant cells.

Is this biologically plausible and what are the proposed biological mechanisms?

An increasing body of in vitro and laboratory research has demonstrated effects of these anaesthetics on immune cell function and cancer cell growth - most of which appear to support the hypothesis that propofol is better than volatile anaesthetics - there could well be something to this.

1 - The effect of different anaesthetics on tumor cytotoxicity by natural killer cells. Toxicol Lett. 2017 Jan 15;266:23-31.

2 - Propofol inhibits invasion and growth of ovarian cancer cells via regulating miR-9/NF-κB signal.Braz J Med Biol Res. 2016 Dec 12;49(12):e5717.

Volatile anaesthetics like sevoflurane have been shown to enhance HIFs - hypoxia inducible factors - they are known to be involved in the regulation of cell survival and apoptosis etc.