(Nov 8) THE war on advanced colon cancer just got sneakier.

Doctors here have found a way to sneak a patient's white blood cells back into the body as trained killers.

This is expected to prolong the lives of advanced colon cancer patients.

Now undergoing clinical trial, the vaccine treatment activates the patient's immune system to fight the cancer.

The trial, involving 20 patients with advanced colon cancer, showed a significant 35 per cent control of the disease, a marked improvement over the 11.2 per cent response rate in current treatments, said principal investigator Toh Han Chong.

In the treatment process, the researchers drew blood samples from the 20 patients, whose average age was 70.

'From the blood, the white cells are separated and processed to create dendritic cells,' Dr Toh said.

Dendritic cells (DCs) are present in the skin and the inner lining of the nose, lungs, stomach and intestines.

These cells can also be found in an 'immature' state in the blood. Being immune cells, DCs can stimulate an immune response.

Dr Toh said tumour lysate - a solution containing a breakdown of the cancer cells and proteins - is then introduced to the DCs to create 'a killer cocktail that stimulates the immune system and causes the cancer to shrink'.

This vaccine is then injected into the patient's body, under the skin.

Dr Toh said the vaccine treatment re-introduces a highly trained special force into the community.

'This special force will, in turn, train T-cells to hone in on specific tumour proteins and kill them,' he said.

The whole process is labour-intensive, taking seven days to process in the lab.

But the results speak for themselves: 40 per cent of the trial subjects - eight of the 20 - survived more than a year after treatment started.

'Bear in mind that these are patients with end-stage cancer who had been given six to nine months to live,' Dr Toh said.

One such person is Madam Phua Ah Moey, 64, a mother of four and grandmother of seven. She was diagnosed with early colon cancer 10 years ago and went through surgery and chemotherapy.

Her cancer relapsed three years ago and spread to her lungs.

She said: 'I suffered side effects from chemotherapy - vomiting and shivering. I was weak and had fainting spells too.

'When I heard about this new trial which involved only 10 injections in five months, I gladly gave it a go.'

She did not suffer any side effects and is able to do household chores and take care of her two-year-old granddaughter every weekend.

The tumour in her lungs had shrunk by more than 50 per cent.

The results of this Phase 2 clinical trial, conducted by a team from the National Cancer Centre and a Danish biotech company, was disclosed at the first Centennial Conference of the American Association for Cancer Research yesterday.

The team is now preparing for the Phase 3 clinical trial, involving about 300 patients and aimed at demonstrating short- and long-term safety and benefits.