Tasmanian devils with tumours the size of golf balls have had their cancerous growths disappear, after scientists successfully trialled a new way to kick-start the animals' immune system.

"At the end of three months there was nothing there, just a bit of scar tissue" said Menzies Institute for Medical Research immunologist Greg Woods.

The new approach works by alerting the animal's immune system to the presence of the deadly cancer, which is normally able to fly under the radar.

Known as devil facial tumour disease, the highly infectious cancer kills devils within three to five months of the facial tumours first appearing.

However the devils in the trial had their tumours vanish - three months after being injected with live cancer cells.

"It sounds a bit counterintuitive because we are treating a cancer with a cancer," Professor Woods said.

The difference was that the live cancer cells injected also contained hormones found in the immune system called cytokines. These made the immune system recognise the cancer as a foreign body prompting the body's footsoldiers, or T-cells, to attack.

"It acted like a switch and turned the immune system on," Professor Woods said.

Better still, the researchers could see what was happening under the microscope: they took a biopsy of the tumour and observed immune cells flooding the tumour site.

"It was just amazing, within a week the whole tumour was just surrounded," Professor Woods said. "The tumour was killed very quickly."

Three of the five Tasmanian devils injected with the live cancer cells containing the immune system hormones had their tumours vanish. The three devils were monitored for a year after the tumours disappeared and there was no evidence that the cancer returned.

Scientists speculate that the two devils which didn't respond could have failed to have their immune system activated because the cytokines could have been added too early and suppressed an immune response.

Nevertheless Professor Woods said the results of the study, published in the journal Scientific Reports, confirm that the best way to tame the fatal cancer was by tapping into the devil's own immune system.

"The exciting thing is that we are working towards a vaccine and for a vaccine to work, the immune system has to target the tumour cells and kill them," Professor Woods said. "We now have evidence that that can happen."

The devil facial tumour disease was first documented in 1996. Then there were tens of thousands of devils living in Tasmania. In the years since, between 90 per cent and 95 per cent of devils have disappeared. Just a few thousand remain and the species was listed by the federal government as endangered in 2009.