The cancer has stopped spreading - indeed his cancer markers have decreased - since he started a clinical trial in Wollongong in February.

"I was diagnosed with colorectal cancer in 2011, had an operation late that year and then underwent two chemotherapy treatments, neither of which worked," Mr Walker, 76, said.

"I suffered from a range of side effects including diarrhoea, foot and mouth disease and numbness in my hands and feet.

"Meanwhile, there was no shrinkage of the tumours, no clinical improvement whatsoever, and the cancer spread to both lungs and my stomach."

Mr Walker's wife, Lyn, said her husband had suffered no side effects under the new drug, Deflexifol.

"And for the first time there's been a decrease in his cancer markers," she said.

"It's given us new hope."

Another Wollongong grandfather, Stephen Tsolakis, is also benefiting from the trial overseen by his oncologist, Professor Philip Clingan.

He underwent an operation for bowel cancer in 2007 and subsequent chemotherapy, but the cancer returned in 2012. Another operation and more treatment then ensued.

"Since then I've tried different chemotherapy treatments, all with different side effects," he said.

"One made me lose my hair, another left my fingers and lips numb, all made me feel very lethargic and none worked.

"But after starting this new drug trial I've had no side effects, am feeling so much better and have even gained some weight."

Importantly, wife Dianne added, the 63-year-old's cancer markers had also decreased.

"It's very positive so far," she said.

"There is hope certainly, but there is also improved quality of life."

The project has received federal funding and support from various charities.