Melbourne scientists will spearhead a global study to see whether the use of gas anaesthetics on cancer patients who undergo surgery could contribute to a higher risk of the cancer recurring.

The study, which will run for five years and include 5,700 patients, is likely to shape the way cancer surgeries are managed worldwide, according to Peter MacCallum Cancer Centre's Bernhard Riedel, who is a chief investigator on the project.

Professor Riedel said there was "mounting evidence" that gas-based anaesthetics — also known as "volatile anaesthetics" — could promote the growth of any cancer cells left in the body after surgery.

He said a study on mice had found that those who were given intravenous anaesthesia had higher rates of cancer survival than those who were treated with anaesthetic gases, suggesting gas anaesthetics could increase the risk of a cancer relapse.

"There's some literature that's suggesting … that some of the volatile gases may drive some of the cancer pathways, and so if there's any residual disease or cancer that's left undiagnosed at the time of surgery, this has a chance to get a foothold and lead to recurrence," he said.

Professor Riedel said some hospitals were already favouring the use of intravenous anaesthesia over gas-based anaesthesia in light of those studies, but there was still no "robust" evidence available to warrant a ban on the use of volatile anaesthesia.

Gas anaesthetic still 'safe'

"The workhorse of anaesthesia has always been volatile-based anaesthesia, it's used by the majority of anaesthetists, it's safe … the opportunity to study this and see whether we can make it a little bit safer for the cancer patient is important," Professor Riedel said.

The study's synopsis said 80 per cent of anaesthetists routinely used inhaled anaesthesia and 50 per cent of respondents felt that the anaesthetic technique used impacted cancer outcomes.

"This lack of clinical consensus on optimal anaesthesia reflects the need for a definitive randomised clinical trial," the synopsis stated. The trial — which will involve international collaboration between scientific centres — will examine whether the already widely used intravenous anaesthetic propofol could reduce inflammation and cancer relapse in patients being treated for lung and colorectal cancers.